Cri Թ tical Thinking Luís Moniz Pereira Departamento de Informática FCT/UNL 1st sem. 06/07 Critical Thinking – jump to 14 for slides in English

CriCriԹԹtical Thinkingtical Thinking

Luís Moniz PereiraLuís Moniz Pereira

Departamento de Informática FCT/UNL 1st sem. Departamento de Informática FCT/UNL 1st sem. 06/0706/07

Critical Thinking – jump to 14 for slides in English

EnquadramentoEnquadramento

Disciplina da área de “soft skills”.Disciplina da área de “soft skills”.

Tem uma relevância geral para qualquer Tem uma relevância geral para qualquer

área científica, em particular para a área científica, em particular para a

Informática, pela forte ligação com a Informática, pela forte ligação com a

lógica para análise de argumentos, lógica para análise de argumentos,

hipóteses, e especificações de problemas hipóteses, e especificações de problemas

ou soluções.ou soluções.

Objectivos – “Saber”Objectivos – “Saber” Interpretar correctamente experiências ou dados Interpretar correctamente experiências ou dados

experimentais.experimentais.

Inferir conclusões a partir de informações dadas, Inferir conclusões a partir de informações dadas,

e ajuizar da credibilidade das fontes.e ajuizar da credibilidade das fontes.

Identificar erros de inferência ou contradições e Identificar erros de inferência ou contradições e

resolvê-las (resolvê-las (debuggingdebugging).).

Saber argumentar e identificar compromissos, Saber argumentar e identificar compromissos,

bem como lidar com ambiguidades e avaliar bem como lidar com ambiguidades e avaliar

opções.opções.

Perceber explicações lógicas e de causalidade.Perceber explicações lógicas e de causalidade.

Objectivos – “Fazer”Objectivos – “Fazer”

Elaborar argumentos válidos e gerir hipóteses Elaborar argumentos válidos e gerir hipóteses

e contextos.e contextos.

Comunicar ideias e sua sustentação lógica.Comunicar ideias e sua sustentação lógica.

Descrever correctamente experiências, Descrever correctamente experiências,

resultados, e conclusões.resultados, e conclusões.

Preferir hipóteses explicativas e testá-las.Preferir hipóteses explicativas e testá-las.

Dar e interpretar explicações causais e lidar Dar e interpretar explicações causais e lidar

com suas alternativas.com suas alternativas.

Objectivos – “Soft Skills”Objectivos – “Soft Skills”

Comunicação e debate. Precisão de linguagem.Comunicação e debate. Precisão de linguagem.

Pensamento crítico. Procura de fontes de Pensamento crítico. Procura de fontes de

informação.informação.

Raciocínio disciplinado.Raciocínio disciplinado.

Avaliação objectiva de argumentos e factos.Avaliação objectiva de argumentos e factos.

Capacidade de decidir usando Capacidade de decidir usando trade-offstrade-offs sobre sobre

valores de utilidade.valores de utilidade.

Esforço do aluno - ECTSEsforço do aluno - ECTS

Número usual de semanas por semestre é 14 Horas por crédito 28

Horas por Semana Semanas Horas

Aulas Teóricas 2 14 28

Aulas teórico-práticas

Aulas práticas e laboratoriais 2 14 28

Seminários

Estágio

Orientação tutorial 4

Outras 10

Projectos e trabalhos 30

Estudo 60

Avaliação 6

Total de Horas 166

ECTS 6

Funcionamento - DocentesFuncionamento - Docentes DocentesDocentes

– TeóricasTeóricas:: 33as as 17–19 anfiteatro 1.27 II17–19 anfiteatro 1.27 II

Prof. Cat. Prof. Cat. Luís Moniz PereiraLuís Moniz [email protected]@di.fct.unl.pthttphttp://centria.di.fct.unl.pt/~lmp/://centria.di.fct.unl.pt/~lmp/gab. 2.47 Ed II, ext. 10717gab. 2.47 Ed II, ext. 10717 atendimento: 3atendimento: 3asas 12-13 12-13

– Práticas Práticas (3 turnos)(3 turnos):: 66asas 9–11, 11–13, 14-16 sala 3.5 Ed. 9–11, 11–13, 14-16 sala 3.5 Ed.

VIIVII

Prof. Aux. Prof. Aux. Ludwig KrippahlLudwig [email protected]@di.fct.unl.pthttp://centria.di.fct.unl.pt/~ludi/http://centria.di.fct.unl.pt/~ludi/gab. 2.41 Ed II, ext. 10765gab. 2.41 Ed II, ext. 10765 atendimento: 6atendimento: 6asas 13-14 13-14

Funcionamento – Página PCFuncionamento – Página PC Sítio Sítio http://ssdi.di.fct.unl.pt/lei/pc/http://ssdi.di.fct.unl.pt/lei/pc/ com: com:

– Objectivos, programa, avaliação, etcObjectivos, programa, avaliação, etc

– Sumários das teóricas e das práticasSumários das teóricas e das práticas

– Slides e gravação digital de som de cada aulaSlides e gravação digital de som de cada aula

– Documentação, exercícios, resultados da avaliaçãoDocumentação, exercícios, resultados da avaliação

– Links externosLinks externos

– SoftwareSoftware

– Lista de distribuição de mail, Lista de distribuição de mail, subscrevamsubscrevam ! ! https://mail.di.fct.unl.pt/mailman/listinfo/lei-pchttps://mail.di.fct.unl.pt/mailman/listinfo/lei-pc

– Mail para envio de trabalhos: Mail para envio de trabalhos: [email protected]@di.fct.unl.pt

Funcionamento – Avaliação Funcionamento – Avaliação 11

Componente prática com 4 fichas Componente prática com 4 fichas individuaisindividuais, , de cerca de 100 palavras, aproximadamente de cerca de 100 palavras, aproximadamente cada 2-3 aulas. Estima-se em 4 horas o cada 2-3 aulas. Estima-se em 4 horas o esforço para cada ficha.esforço para cada ficha.

Dois trabalhos Dois trabalhos individuaisindividuais, de cerca de 500 , de cerca de 500 palavras cada. Estima-se em 15 horas o palavras cada. Estima-se em 15 horas o esforço para cada trabalho.esforço para cada trabalho.

Participação e desempenho nas discussões Participação e desempenho nas discussões das aulas práticas.das aulas práticas.

Estas componentes valem 40% da nota final. Estas componentes valem 40% da nota final.

Funcionamento – Avaliação Funcionamento – Avaliação 22

Exame final escrito de 2 horas:Exame final escrito de 2 horas:– Com algo como 4 perguntas das quais se podem Com algo como 4 perguntas das quais se podem

escolher 2, com respostas de desenvolvimento.escolher 2, com respostas de desenvolvimento.

– As respostas não são necessariamente longas (e.g. As respostas não são necessariamente longas (e.g. 3-4 páginas), mas terão material para consultar 3-4 páginas), mas terão material para consultar (algumas páginas), e que criar um argumento (algumas páginas), e que criar um argumento estruturado, o que poderá exigir alguns rascunhos.estruturado, o que poderá exigir alguns rascunhos.

Esta componente vale 60% da nota final.Esta componente vale 60% da nota final.

ObrigatoriedadeObrigatoriedade de presença em 9T e em 9P. de presença em 9T e em 9P.

Programa - 1Programa - 1 Estrutura de argumentosEstrutura de argumentos

– Estrutura lógica formal.Estrutura lógica formal.

– Requisitos de validade. Ambiguidade.Requisitos de validade. Ambiguidade.

Erros em argumentos falaciososErros em argumentos falaciosos

– Erros de raciocínio. Remoção de Erros de raciocínio. Remoção de contradições.contradições.

– Mau uso da evidência.Mau uso da evidência.

– Erros linguísticos e recurso a considerações Erros linguísticos e recurso a considerações pessoais.pessoais.

Programa - 2Programa - 2 Avaliação críticaAvaliação crítica

– Avaliação de experiências pessoais.Avaliação de experiências pessoais.

– Crença e conhecimento.Crença e conhecimento.

– Afirmações e o ónus da prova.Afirmações e o ónus da prova.

Comunicação e fontes de informaçãoComunicação e fontes de informação

Decisão e "trade-offs"Decisão e "trade-offs"

– Avaliação de opções. Avaliação de opções. – Enviezamentos. Equilíbrios.Enviezamentos. Equilíbrios.

Programa - 3Programa - 3 Raciocínio CientíficoRaciocínio Científico

– Importância da testabilidade de hipóteses. Importância da testabilidade de hipóteses.

– Preferências explicativas.Preferências explicativas.

– Modelos teóricos e sua avaliação. Modelos teóricos e sua avaliação.

– Epistemologia.Epistemologia.

– Hipóteses causais e estatísticas.Hipóteses causais e estatísticas.

– Reproductibilidade, confirmaçãoReproductibilidade, confirmaçãoindependente, e independente, e arbitragem.arbitragem.

Main BibliographyMain Bibliography Alec Fisher, 2001, Alec Fisher, 2001, Critical Thinking - an Critical Thinking - an

introductionintroduction, , Cambridge U.P.Cambridge U.P.

Jonathan Baron, 2000, Jonathan Baron, 2000, Thinking and DecidingThinking and Deciding,,

Cambridge U.P., 3Cambridge U.P., 3rdrd ed. ed.

Ronald Griere, 1997, Ronald Griere, 1997, Understanding Scientific Understanding Scientific

ReasoningReasoning, , Harcourt Brace, 4Harcourt Brace, 4thth ed. ed.

Douglas Walton, 2004, Douglas Walton, 2004, Abductive ReasoningAbductive Reasoning,,

The University of Alabama Press.The University of Alabama Press.

M. Neil Browne, Stuart M. Keeley, 2004, M. Neil Browne, Stuart M. Keeley, 2004, Asking the Asking the

Right Right QuestionsQuestions, Pearson Prentice Hall, 7, Pearson Prentice Hall, 7thth ed. ed.

Two sides of the coinTwo sides of the coin Critical thinking has two sides to it:Critical thinking has two sides to it:

- That of the - That of the consumerconsumer of information. of information.

- That of the - That of the producerproducer..

Often, the stress is put just on the general public, Often, the stress is put just on the general public, viewed as the critical consumer.viewed as the critical consumer.

Here, we shall stress the critical producer side too: Here, we shall stress the critical producer side too: university students are trained to be producers of university students are trained to be producers of knowledgeknowledge, , activitiesactivities, , decisionsdecisions and and designsdesigns, and , and hence should strive to be self-critical producers.hence should strive to be self-critical producers.

Definitions – Definitions – JohnJohn DeweyDewey

Critical thinkingCritical thinking is the active, persistent, is the active, persistent,

and careful consideration of a belief or and careful consideration of a belief or

supposed form of knowledge, in the light supposed form of knowledge, in the light

of the grounds which support it, and the of the grounds which support it, and the

further conclusions to which it tends.further conclusions to which it tends.

Definitions – Definitions – Edward Glaser Edward Glaser onon DeweyDewey

Critical thinkingCritical thinking is: is:

- An attitude of being disposed to consider, in a - An attitude of being disposed to consider, in a thoughtful way, the problems and and subjects that thoughtful way, the problems and and subjects that come within the range of one’s experience.come within the range of one’s experience.

- Knowledge of the methods of logical inquiry and - Knowledge of the methods of logical inquiry and reasoning, and some skill in applying those methods.reasoning, and some skill in applying those methods.

It calls for a persistent effort to examine any belief or It calls for a persistent effort to examine any belief or supposed form of knowledge in the light of the supposed form of knowledge in the light of the evidence that supports it and the further conclusions evidence that supports it and the further conclusions to which it tends.to which it tends.

Definitions – Definitions – RobertRobert EnnisEnnis

Critical thinkingCritical thinking is reasonable, reflective is reasonable, reflective thinking that is focussed on deciding what thinking that is focussed on deciding what to believe or do.to believe or do.

Definitions – Definitions – Richard PaulRichard Paul

Critical thinkingCritical thinking is that mode of thinking – is that mode of thinking –

about any subject, content or problem – in about any subject, content or problem – in

which the thinker improves the quality of which the thinker improves the quality of

his thinking, by skilfully taking charge of his thinking, by skilfully taking charge of

the structures inherent in thinking and the structures inherent in thinking and

imposing intellectual standards upon them.imposing intellectual standards upon them.

Definitions – Definitions – Michael ScrivenMichael Scriven

Critical thinkingCritical thinking is skilled and active is skilled and active

interpretation and evaluation of interpretation and evaluation of

observations and communications, observations and communications,

information and argumentation.information and argumentation.

Definitions – Definitions – Wikipedia 1Wikipedia 1

Critical thinking consists of a mental process of analyzing or evaluating information, particularly statements or propositions that people have offered as true.

It forms a process of reflecting upon the meaning of statements, examining the offered evidence and reasoning, and forming judgments about the facts.


Critical thinkers can gather such information from observation, experience, reasoning, and/or communication.

Critical thinking has its basis in intellectual values that go beyond subject-matter divisions and which include: clarity, accuracy, precision, evidence, thoroughness and fairness.


The process of The process of critical thinkingcritical thinking involves involves

acquiring information and evaluating it to reach acquiring information and evaluating it to reach

a well-justified conclusion or answer.a well-justified conclusion or answer.

Part of Part of critical thinkingcritical thinking comprises informal logic. comprises informal logic.

Given research in cognitive psychology, Given research in cognitive psychology,

educators increasingly believe that schools educators increasingly believe that schools

should focus more on teaching their students should focus more on teaching their students

critical thinkingcritical thinking skills than on memorizing facts skills than on memorizing facts

by rote-learning. by rote-learning.

Definitions – Definitions – William G. Sumner William G. Sumner 11

Critical thinkingCritical thinking is the examination and test is the examination and test

of propositions of any kind which are offered of propositions of any kind which are offered

for acceptance, in order to find out whether for acceptance, in order to find out whether

they correspond to reality or not.they correspond to reality or not.

The The critical facultycritical faculty is a product of education is a product of education

and training. It is a mental habit and power.and training. It is a mental habit and power.

Definitions – Definitions – William G. Sumner William G. Sumner 22

Critical thinkingCritical thinking is such a prime condition is such a prime condition

of human welfare that men and women of human welfare that men and women

should be trained in it.should be trained in it.

Critical thinkingCritical thinking is our only guarantee is our only guarantee

against delusion, deception, superstition, against delusion, deception, superstition,

and misapprehension of ourselves and our and misapprehension of ourselves and our

earthly circumstances. earthly circumstances.

BootstrapBootstrap

Thinking critically aboutThinking critically about

critical thinkingcritical thinking ! !

Critical thinking is criticalCritical thinking is critical ! !

Argumentation - 1Argumentation - 1

We often encounter situations in We often encounter situations in which someone is trying to persuade which someone is trying to persuade us of a point of view by presenting us of a point of view by presenting reasons for it.reasons for it.

This is called “arguing a case” or This is called “arguing a case” or “presenting an argument”.“presenting an argument”.

Argumentation - 2Argumentation - 2

Sometimes it is easy to to see what the Sometimes it is easy to to see what the issues and conclusions are, and the issues and conclusions are, and the reasons presented, but sometimes not.reasons presented, but sometimes not.

Before we evaluate and argue a point Before we evaluate and argue a point of view we must identify its issues, of view we must identify its issues, conclusions, and reasons. conclusions, and reasons.

And then clearly present our own.And then clearly present our own.

Asking the right questions - Asking the right questions - 11

1.1. What are the issues and the conclusions?What are the issues and the conclusions?

2.2. What are the reasons?What are the reasons?

3.3. Which words or phrases are ambiguous?Which words or phrases are ambiguous?

4.4. What are the value conflicts and What are the value conflicts and

assumptions?assumptions?

5.5. What are the descriptive assumptions?What are the descriptive assumptions?

6.6. Are there any fallacies in the reasoning?Are there any fallacies in the reasoning?

Asking the right questions - Asking the right questions - 22

7.7. How good is the evidence?How good is the evidence?

8.8. Are there rival causes?Are there rival causes?

9.9. Are the statistics deceptive?Are the statistics deceptive?

10.10. What significant information is omitted?What significant information is omitted?

11.11. What reasonable conclusions are What reasonable conclusions are

possible?possible?

12.12. Are the best practice precepts followed?Are the best practice precepts followed?

What are the issues and What are the issues and conclusions? - 1conclusions? - 1

Before we can evaluate an author’s Before we can evaluate an author’s

argument, we must clearly identify the argument, we must clearly identify the

issues and conclusions.issues and conclusions.

How can we evaluate an argument if we How can we evaluate an argument if we

don’t know exactly what the author is trying don’t know exactly what the author is trying

to persuade us to believe?to persuade us to believe?

Finding an author’s main points is the first Finding an author’s main points is the first

step in deciding whether we will accept or step in deciding whether we will accept or

reject it.reject it.


An An issueissue is a question or controversy is a question or controversy responsible for the conversation or responsible for the conversation or discussion. It is the stimulus for what is discussion. It is the stimulus for what is being said.being said.

Descriptive issuesDescriptive issues are those that raise are those that raise questions about the accuracy of questions about the accuracy of descriptions of the past, present, or future.descriptions of the past, present, or future.

Prescriptive issuesPrescriptive issues are those that raise are those that raise questions about what we should do, or what questions about what we should do, or what is right or wrong, good or bad.is right or wrong, good or bad.

A A conclusionconclusion is the message that the is the message that the speaker or writer wishes you to accept.speaker or writer wishes you to accept.


CluesClues for finding them: for finding them:– Ask Ask what the issue iswhat the issue is: look at title and opening : look at title and opening

paragraphs; skim through.paragraphs; skim through.

– Look for Look for indicator wordsindicator words: the truth is, hence, ...: the truth is, hence, ...

– Look in likely Look in likely locationslocations: beginning, end, summary.: beginning, end, summary.

– Remember Remember what a conclusion is notwhat a conclusion is not: examples, ...: examples, ...

– Check the Check the author’s contextauthor’s context: background, : background,

organizations, bias, ...organizations, bias, ...

– Ask the question “Ask the question “and therefore?and therefore?””

What are the reasons? - 1What are the reasons? - 1

Once we have identified an issue and Once we have identified an issue and

conclusion, we need to understand conclusion, we need to understand whywhy an an

author has come to that conclusion. Reasons author has come to that conclusion. Reasons

are the are the whywhy..

If the author provides good reasons, we might If the author provides good reasons, we might

be persuaded to accept the conclusion. First, be persuaded to accept the conclusion. First,

we are simply concerned with identifying the we are simply concerned with identifying the

reasons. Next, we decide whether to accept or reasons. Next, we decide whether to accept or

reject it.reject it.


Inferential reasonsInferential reasons are explanations offered are explanations offered

as a basis for why we should believe a as a basis for why we should believe a

particular conclusion.particular conclusion. They rely on facts, evidence, assumptions, They rely on facts, evidence, assumptions,

and inferences.and inferences.

They have an intent.They have an intent.

Their quality varies.Their quality varies.

Argument = Conclusion + ReasonsArgument = Conclusion + Reasons

We distinguish them from We distinguish them from causal reasonscausal reasons..


CluesClues for finding them: for finding them:

1.1. Circle indicator words.Circle indicator words.

2.2. Underline reasons and conclusions in Underline reasons and conclusions in different colour, and label them.different colour, and label them.

3.3. After reading long passages, make a list After reading long passages, make a list of the reasons and conclusions in them.of the reasons and conclusions in them.

4.4. Use a diagram structure with arrows and Use a diagram structure with arrows and labels to designate relationships labels to designate relationships between reasons and conclusions.between reasons and conclusions.

Value conflicts and Value conflicts and assumptions - 1assumptions - 1

While an author usually offers explicit While an author usually offers explicit reasons why he comes to a certain reasons why he comes to a certain conclusion, he also makes (implicit) conclusion, he also makes (implicit) assumptions leading to it, on the basis of assumptions leading to it, on the basis of his values.his values.

By identifying value conflicts, we By identifying value conflicts, we determine whether the author’s value determine whether the author’s value preferences match our own, and can preferences match our own, and can then dispute them.then dispute them.


Value assumptions usually are:Value assumptions usually are:

– Hidden or unstated (in most cases).Hidden or unstated (in most cases).

– Taken for granted.Taken for granted.

– Influential in determining the conclusion.Influential in determining the conclusion.

– Potentially deceptive.Potentially deceptive.


CluesClues for finding them: for finding them:

– Investigate the author’s background.Investigate the author’s background.

– Ask “Why do the consequences of the Ask “Why do the consequences of the

author’s position seem so important to him?”author’s position seem so important to him?”

– Search for similar social controversies, in Search for similar social controversies, in

order to find analogue value assumptions.order to find analogue value assumptions.

– Use reverse role-playing, by taking his Use reverse role-playing, by taking his

position.position.

– Look for usual value conflicts.Look for usual value conflicts.

What are the descriptive What are the descriptive assumptions? - 1assumptions? - 1

When we identify descriptive When we identify descriptive

assumptions, we find the link between a assumptions, we find the link between a

reason and the author’s conclusion, and it reason and the author’s conclusion, and it

may be flawed.may be flawed.

We want to accept a conclusion only if We want to accept a conclusion only if

there are good reasons that lead to the there are good reasons that lead to the

conclusion on the basis of the descriptive conclusion on the basis of the descriptive

assumptions.assumptions.

What are the descriptive What are the descriptive assumptions? - 2assumptions? - 2

CluesClues to finding them: to finding them:

– Keep thinking about the gap between Keep thinking about the gap between

conclusion and reasons.conclusion and reasons.

– Look for ideas that support reasons.Look for ideas that support reasons.

– Identify with the opposition.Identify with the opposition.

– Recognize the potential existence of Recognize the potential existence of other means for attaining the other means for attaining the advantages referred in the reasons.advantages referred in the reasons.

– Learn more about the issues.Learn more about the issues.

The Socratic method - 1The Socratic method - 1

What do you mean by _____________ ? What do you mean by _____________ ?

How did you come to that conclusion? How did you come to that conclusion?

Why do you believe that you are right? Why do you believe that you are right?

What is the source of your information? What is the source of your information?

What assumption has led you to that What assumption has led you to that

conclusion? conclusion?

(see Wikipedia)(see Wikipedia)

The Socratic method - 2The Socratic method - 2

What happens if you are wrong? What happens if you are wrong?

Can you give me two sources who Can you give me two sources who

disagree with you and explain why? disagree with you and explain why?

Why is this significant? Does it matter?Why is this significant? Does it matter?

How do I know you are telling me the How do I know you are telling me the

truth? truth?

What is an alternate explanation for this What is an alternate explanation for this

phenomenon?phenomenon?

Best Practice Precepts Best Practice Precepts [... [... next]next]

ArgumentsArguments

Possibility of the ImpossiblePossibility of the Impossible

Belief, Truth, and RealityBelief, Truth, and Reality

Knowledge, Belief, and EvidenceKnowledge, Belief, and Evidence

Scientific ThinkingScientific Thinking

BiasBias

Arguments - 1Arguments - 1

A.A. Itemize opinions from all relevant sides of Itemize opinions from all relevant sides of

an issue and collect logical arguments an issue and collect logical arguments

supporting each. supporting each.

B.B. Break the arguments into their constituent Break the arguments into their constituent

statements and draw out various additional statements and draw out various additional

implications from these statements. implications from these statements.

C.C. Examine these statements and implications Examine these statements and implications

for internal contradictions. for internal contradictions.

Arguments - 2Arguments - 2D.D. Locate opposing claims between the Locate opposing claims between the

various arguments and assign relative various arguments and assign relative weightings to opposing claims: weightings to opposing claims:

– Increase the weighting when the claims Increase the weighting when the claims

have strong support, especially distinct have strong support, especially distinct

chains of reasoning or different news chains of reasoning or different news

sources, decrease the weighting when the sources, decrease the weighting when the

claims have contradictions.claims have contradictions.

– ......


– Adjust weighting depending on relevance Adjust weighting depending on relevance

of information to central issue. of information to central issue.

– Require sufficient support to justify any Require sufficient support to justify any

incredible claims.incredible claims.

– Otherwise, ignore these claims when Otherwise, ignore these claims when

forming a judgment.forming a judgment.

E.E. Assess the weights of the various claims.Assess the weights of the various claims.


F.F. Once we have identified an argument, we identify Once we have identified an argument, we identify

keywords or phrases within its reasoning, that keywords or phrases within its reasoning, that

might have alternative well-defined meanings.might have alternative well-defined meanings.

G.G. We determine whether or not the author We determine whether or not the author

explicitly uses one of those definitions. If not, and explicitly uses one of those definitions. If not, and

one of them changes our acceptance of the one of them changes our acceptance of the

conclusion, then an ambiguity has been conclusion, then an ambiguity has been

identified.identified.

H.H. This is an important step in accepting or not This is an important step in accepting or not

some conclusion.some conclusion.

Possibility of the Impossible Possibility of the Impossible - 1- 1

A.A. Just because something is logically possible Just because something is logically possible

doesn’t mean that it’s real.doesn’t mean that it’s real.

B.B. Just because a claim hasn’t been conclusively Just because a claim hasn’t been conclusively

refuted doesn’t mean that it’s true.refuted doesn’t mean that it’s true.

C.C. Just because a claim hasn’t been conclusively Just because a claim hasn’t been conclusively

proven doesn’t mean that it’s false.proven doesn’t mean that it’s false.

Possibility of the Impossible Possibility of the Impossible - 2- 2

D.D. Just because something seems physically Just because something seems physically impossible doesn’t mean that it is.impossible doesn’t mean that it is.

E.E. Just because something is physically Just because something is physically possible doesn’t mean that it’s real.possible doesn’t mean that it’s real.

F.F. One can’t believe impossible things.One can’t believe impossible things.

G.G. We have to live today by what truth we We have to live today by what truth we can get today, and be ready tomorrow to can get today, and be ready tomorrow to call it falsehood.call it falsehood.

Belief, Truth, and Reality - 1Belief, Truth, and Reality - 1

A.A. Just because you believe that something Just because you believe that something

is true doesn’t mean that it is.is true doesn’t mean that it is.

B.B. Just because a group of people believe Just because a group of people believe

that something is true doesn’t mean that that something is true doesn’t mean that

it is.it is.

C.C. There is such a thing as objective truth.There is such a thing as objective truth.

Belief, Truth, and Reality - 2Belief, Truth, and Reality - 2

D.D. Facts do not cease to exist because they Facts do not cease to exist because they

are ignored. are ignored.

E.E. Truth is something we can attempt to Truth is something we can attempt to

doubt, and then perhaps, after much doubt, and then perhaps, after much

exertion, discover that part of the doubt exertion, discover that part of the doubt

is unjustified.is unjustified.

Knowledge, Belief, and Knowledge, Belief, and Evidence - 1Evidence - 1

A.A. We are justified in believing a proposition when We are justified in believing a proposition when we have no good reason to doubt it.we have no good reason to doubt it.

B.B. There is good reason to doubt a proposition if There is good reason to doubt a proposition if it conflicts with other propositions we have it conflicts with other propositions we have good reason to believe.good reason to believe.

C.C. The more background information a The more background information a proposition conflicts with, the more reason proposition conflicts with, the more reason there is to doubt it.there is to doubt it.


D.D. When there is good reason to doubt a When there is good reason to doubt a proposition, we should proportion our proposition, we should proportion our belief to the evidence.belief to the evidence.

E.E. There is good reason to doubt a There is good reason to doubt a proposition if it conflicts with expert proposition if it conflicts with expert opinion.opinion.

F.F. Just because someone is an expert in one Just because someone is an expert in one field doesn’t mean that he is an expert in field doesn’t mean that he is an expert in another.another.


G.G. If we have no reason to doubt what’s If we have no reason to doubt what’s disclosed to us through perception, disclosed to us through perception, introspection, memory, or reason, then introspection, memory, or reason, then we’re justified in believing it.we’re justified in believing it.

H.H. To doubt everything or to believe To doubt everything or to believe everything are two equally convenient everything are two equally convenient solutions; both dispense with the solutions; both dispense with the necessity of reflection.necessity of reflection.

Scientific Thinking - 1Scientific Thinking - 1

A.A. It is not what the man of science believes It is not what the man of science believes that distinguishes him, but how and why he that distinguishes him, but how and why he believes it.believes it.

B.B. A hypothesis is scientific only if it is testable, A hypothesis is scientific only if it is testable, that is, only if it predicts something other that is, only if it predicts something other than what it was introduced to explain. A than what it was introduced to explain. A hypothesis should state the test conditions hypothesis should state the test conditions that could render it false – that could render it false – falsifiabilityfalsifiability..


C.C. Other things being equal, the best Other things being equal, the best hypothesis is the one that is the most hypothesis is the one that is the most fruitful, that is, makes the most novel fruitful, that is, makes the most novel predictions.predictions.

D.D. Other things being equal, the best Other things being equal, the best hypothesis is the one that has the hypothesis is the one that has the greatest scope, that is, that explains and greatest scope, that is, that explains and predicts the most diverse phenomena.predicts the most diverse phenomena.


E.E. Other things being equal, the best Other things being equal, the best hypothesis is the simplest one, that is, hypothesis is the simplest one, that is, the one that makes the fewest the one that makes the fewest assumptions.assumptions.

F.F. Other things being equal, the best Other things being equal, the best hypothesis is the most conservative, that hypothesis is the most conservative, that is, the one that fits best with established is, the one that fits best with established beliefs.beliefs.


G.G. We should accept an extraordinary We should accept an extraordinary

hypothesis only if no ordinary one will do.hypothesis only if no ordinary one will do.

H.H. When two or more hypotheses compete, When two or more hypotheses compete,

we should make a new observation, the we should make a new observation, the

result of which shall eliminate some of result of which shall eliminate some of

them.them.

Occam's razor – 1Occam's razor – 1

The The Occam's razorOccam's razor principle principle (of William of (of William of

Ockham)Ockham) states that the explanation of states that the explanation of

any phenomenon should make as few any phenomenon should make as few

assumptions as possible, eliminating, or assumptions as possible, eliminating, or

"shaving off", the observable "shaving off", the observable

predictions of the explanatory predictions of the explanatory

hypothesis or theory.hypothesis or theory.

(see Wikipedia)(see Wikipedia)

Occam's razor – 2Occam's razor – 2

Given two equally valid explanations for a Given two equally valid explanations for a

phenomenon, one should embrace the phenomenon, one should embrace the

less complicated formulation. less complicated formulation.

And, when multiple competing theories And, when multiple competing theories

have equal predictive powers, select those have equal predictive powers, select those

that introduce the fewest assumptions and that introduce the fewest assumptions and

the fewest hypothetical entities.the fewest hypothetical entities.

BiasBias Critical thinking does not assure that one Critical thinking does not assure that one

will reach either the truth or correct will reach either the truth or correct conclusions.conclusions.

First, one may not have all the relevant First, one may not have all the relevant information; indeed, important information information; indeed, important information may remain undiscovered, or the may remain undiscovered, or the information may not even be knowable.information may not even be knowable.

Second, one's biases may prevent effective Second, one's biases may prevent effective gathering and evaluation of the available gathering and evaluation of the available information. information.

Bias typesBias types

Decision making biasesDecision making biases

Behavioural biasesBehavioural biases

Biases in probability and beliefBiases in probability and belief

Social biasesSocial biases

Decision making + behavioural biases Decision making + behavioural biases 11

Bandwagon effectBandwagon effect - the tendency to do or believe - the tendency to do or believe

things because many others do or believe the things because many others do or believe the

same. same.

Bias blind spotBias blind spot - the tendency not to compensate - the tendency not to compensate

for one's own cognitive biases. for one's own cognitive biases.

Choice-supportive biasChoice-supportive bias - the tendency to remember - the tendency to remember

one's choices as better than they actually were. one's choices as better than they actually were.

Confirmation biasConfirmation bias - the tendency to search for or - the tendency to search for or

interpret information in a way that confirms one's interpret information in a way that confirms one's

preconceptions. preconceptions.


Congruence biasCongruence bias - the tendency to test - the tendency to test

hypotheses exclusively through direct testing, hypotheses exclusively through direct testing,

without considering testing their without considering testing their

consequences.consequences.

Contrast effectContrast effect - the enhancement or - the enhancement or

diminishment of a weight or other diminishment of a weight or other

measurement when compared with recently measurement when compared with recently

observed contrasting object. observed contrasting object.

Disconfirmation bias - the tendency to Disconfirmation bias - the tendency to

extend critical scrutiny to information extend critical scrutiny to information

which contradicts prior beliefs, and to which contradicts prior beliefs, and to

accept uncritically information that is accept uncritically information that is

congruent with prior beliefs.congruent with prior beliefs.

Endowment effectEndowment effect - the tendency to value - the tendency to value

something more as soon as you own it. something more as soon as you own it.



Focusing effect - prediction bias occurring Focusing effect - prediction bias occurring

when you place too much importance on one when you place too much importance on one

aspect of an event; causes error in accurately aspect of an event; causes error in accurately

predicting the utility of a future outcome. predicting the utility of a future outcome.

Hyperbolic discounting - the tendency to have Hyperbolic discounting - the tendency to have

a stronger preference for more immediate a stronger preference for more immediate

payoffs relative to later payoffs, the closer to payoffs relative to later payoffs, the closer to

the present time both payoffs are. the present time both payoffs are.

Decision making + behavioural Decision making + behavioural biases 5biases 5

Illusion of control - the tendency to believe Illusion of control - the tendency to believe

you can control or at least influence you can control or at least influence

outcomes which you clearly cannot.outcomes which you clearly cannot.

Impact bias - the tendency to overestimate Impact bias - the tendency to overestimate

the length or the intensity of the impact of the length or the intensity of the impact of

future feeling states. future feeling states.

Information bias - the tendency to seek Information bias - the tendency to seek

information even when it cannot affect information even when it cannot affect

action. action.


Loss aversion - the tendency to strongly Loss aversion - the tendency to strongly

prefer avoiding losses over acquiring gains.prefer avoiding losses over acquiring gains.

Neglect of probability - the tendency to Neglect of probability - the tendency to

completely disregard probability when completely disregard probability when

making a decision under uncertainty.making a decision under uncertainty.

Mere exposure effect - the tendency to Mere exposure effect - the tendency to

express undue liking for things merely express undue liking for things merely

because they are familiar to you.because they are familiar to you.


Omission biasOmission bias - The tendency to judge harmful - The tendency to judge harmful

actions as worse, or less moral than equally actions as worse, or less moral than equally

harmful omissions (inactions). harmful omissions (inactions).

Outcome biasOutcome bias - the tendency to judge a - the tendency to judge a

decision by its eventual outcome instead of decision by its eventual outcome instead of

based on the quality of the decision at the based on the quality of the decision at the

time it was made. time it was made.

Planning fallacyPlanning fallacy - the tendency to - the tendency to

underestimate task-completion times. underestimate task-completion times.


Post-purchase rationalizationPost-purchase rationalization - the tendency - the tendency

to persuade oneself through rational to persuade oneself through rational

argument that a purchase was good value. argument that a purchase was good value.

Pseudocertainty effectPseudocertainty effect - the tendency to - the tendency to

make risk-averse choices if the expected make risk-averse choices if the expected

outcome is positive, but make risk-seeking outcome is positive, but make risk-seeking

choices to avoid negative outcomes. choices to avoid negative outcomes.


Rosy retrospection - the tendency to rate Rosy retrospection - the tendency to rate

past events more positively than you had past events more positively than you had

actually rated them when the event occurred. actually rated them when the event occurred.

Selective perception - the tendency for Selective perception - the tendency for

expectations to affect perception. expectations to affect perception.

Status quo bias - the tendency to like things Status quo bias - the tendency to like things

to stay relatively the same. to stay relatively the same.


von Restorff effect - the tendency for an item von Restorff effect - the tendency for an item

that "stands out like a sore thumb" to be that "stands out like a sore thumb" to be

more likely remembered than other items. more likely remembered than other items.

Zero-risk bias - preference for reducing a Zero-risk bias - preference for reducing a

small risk to zero over a greater reduction in small risk to zero over a greater reduction in

a larger risk.a larger risk.

Biases in probability and belief Biases in probability and belief - 1- 1

Ambiguity effect - the avoidance of options for Ambiguity effect - the avoidance of options for which missing information makes the probability which missing information makes the probability seem "unknown". seem "unknown".

Anchoring - the tendency to rely too heavily, or Anchoring - the tendency to rely too heavily, or "anchor", on one trait or piece of information "anchor", on one trait or piece of information when making decisions.when making decisions.

Anthropic bias - the tendency for one's evidence Anthropic bias - the tendency for one's evidence to be biased by observation selection effects.to be biased by observation selection effects.

Attentional bias - neglect of relevant data when Attentional bias - neglect of relevant data when making judgments of a correlation or making judgments of a correlation or association.association.


Availability heuristic - a biased prediction, Availability heuristic - a biased prediction, due to the tendency to focus on the most due to the tendency to focus on the most salient and emotionally charged outcome. salient and emotionally charged outcome.

Belief bias - the tendency to base Belief bias - the tendency to base assessments on personal beliefs. assessments on personal beliefs.

Belief overkill - the tendency to bring Belief overkill - the tendency to bring beliefs and values together so that they all beliefs and values together so that they all point to the same conclusion.point to the same conclusion.

Clustering illusion - the tendency to see Clustering illusion - the tendency to see patterns where actually none exist.patterns where actually none exist.


Conjunction fallacy - the tendency to Conjunction fallacy - the tendency to assume that specific conditions are more assume that specific conditions are more probable than general ones.probable than general ones.

Gambler's fallacy - the tendency to Gambler's fallacy - the tendency to assume that individual random events are assume that individual random events are influenced by previous random events - influenced by previous random events - "the coin has a memory"."the coin has a memory".

Hindsight bias - sometimes called the "I-Hindsight bias - sometimes called the "I-knew-it-all-along" effect, the inclination to knew-it-all-along" effect, the inclination to see past events as being predictable. see past events as being predictable.


Illusory correlation - beliefs that inaccurately Illusory correlation - beliefs that inaccurately

suppose a relationship between a certain type suppose a relationship between a certain type

of action and an effect.of action and an effect.

My side bias - the tendency for people to fail to My side bias - the tendency for people to fail to

look for or to ignore evidence against what look for or to ignore evidence against what

they already favour.they already favour.

Neglect of prior base rates effect - the Neglect of prior base rates effect - the

tendency to fail to incorporate prior known tendency to fail to incorporate prior known

probabilities which are pertinent to the probabilities which are pertinent to the

decision at hand.decision at hand.


Observer-expectancy effect - when a researcher Observer-expectancy effect - when a researcher expects a given result, and therefore expects a given result, and therefore unconsciously manipulates an experiment or unconsciously manipulates an experiment or misinterprets data in order to find it.misinterprets data in order to find it.

Overconfidence effect - the tendency to Overconfidence effect - the tendency to overestimate one's own abilities.overestimate one's own abilities.

Polarization effect - increase in strength of belief Polarization effect - increase in strength of belief on both sides of an issue after presentation of on both sides of an issue after presentation of neutral or mixed evidence, resulting from neutral or mixed evidence, resulting from biased assimilation of the evidence.biased assimilation of the evidence.


Positive outcome bias (prediction) - a Positive outcome bias (prediction) - a tendency in prediction to overestimate the tendency in prediction to overestimate the probability of good things happening to probability of good things happening to them. them.

Recency effect - the tendency to weigh Recency effect - the tendency to weigh recent events more than earlier events.recent events more than earlier events.

Primacy effect - the tendency to weigh initial Primacy effect - the tendency to weigh initial events more than subsequent events.events more than subsequent events.

Subadditivity effect - the tendency to judge Subadditivity effect - the tendency to judge probability of the whole to be less than the probability of the whole to be less than the conjunction of probabilities of the parts.conjunction of probabilities of the parts.

Social biases - 1Social biases - 1 Forer effect Forer effect (aka Barnum Effect)(aka Barnum Effect) - the tendency for - the tendency for

people to give high accuracy ratings to people to give high accuracy ratings to descriptions of their personality, that supposedly descriptions of their personality, that supposedly are tailored specifically for them, but are in fact are tailored specifically for them, but are in fact vague and general enough to apply to a wide vague and general enough to apply to a wide range of people. range of people.

Egocentric bias - occurs when people claim more Egocentric bias - occurs when people claim more responsibility for themselves for the results of a responsibility for themselves for the results of a joint action than an outside observer would. joint action than an outside observer would.

False consensus effect - the tendency for people False consensus effect - the tendency for people to overestimate the degree to which others to overestimate the degree to which others agree with them.agree with them.

Social biases - 2Social biases - 2 Fundamental attribution error - the Fundamental attribution error - the

tendency to over-emphasize personality-tendency to over-emphasize personality-based explanations for behaviours observed based explanations for behaviours observed in others, while under-emphasizing the role in others, while under-emphasizing the role and power of situational influences on that and power of situational influences on that same behaviour.same behaviour.

Halo effect - the tendency for a person's Halo effect - the tendency for a person's positive or negative traits to "spill over" positive or negative traits to "spill over" from one area of their personality to from one area of their personality to another, in others' perceptions of them.another, in others' perceptions of them.

Illusion of asymmetric insight - people Illusion of asymmetric insight - people perceive their knowledge of their peers to perceive their knowledge of their peers to surpass their peers' knowledge of them. surpass their peers' knowledge of them.

Social biases - 3Social biases - 3 Illusion of transparency - people overestimate Illusion of transparency - people overestimate

others' ability to know them, and they also others' ability to know them, and they also

overestimate their ability to know others. overestimate their ability to know others.

In group bias - preferential treatment people In group bias - preferential treatment people

give to whom they perceive to be members of give to whom they perceive to be members of

their own groups. their own groups.

Just-world phenomenon - the tendency for Just-world phenomenon - the tendency for

people to erroneously believe that the world is people to erroneously believe that the world is

"just" and therefore people "get what they "just" and therefore people "get what they

deserve." deserve."

Social biases - 4Social biases - 4

Lake Wobegon effect - the human tendency to Lake Wobegon effect - the human tendency to

report flattering beliefs about oneself and report flattering beliefs about oneself and

believe that one is above average. believe that one is above average.

Notational bias - a form of cultural bias in Notational bias - a form of cultural bias in

which a notation induces the appearance of a which a notation induces the appearance of a

nonexistent natural law. nonexistent natural law.

Outgroup homogeneity bias - individuals see Outgroup homogeneity bias - individuals see

members of their own group as being members of their own group as being

relatively more varied than members of other relatively more varied than members of other

groups. groups.


Projection bias - the tendency to Projection bias - the tendency to

unconsciously assume that others share the unconsciously assume that others share the

same or similar thoughts, beliefs, values, or same or similar thoughts, beliefs, values, or

positions. positions.

Self-serving bias - the tendency to claim Self-serving bias - the tendency to claim

more responsibility for successes than more responsibility for successes than

failures. It may manifest itself as a tendency failures. It may manifest itself as a tendency

for you to evaluate ambiguous information in for you to evaluate ambiguous information in

a way beneficial to your interests.a way beneficial to your interests.


Trait ascription bias - the tendency for people to Trait ascription bias - the tendency for people to

view themselves as relatively variable in terms of view themselves as relatively variable in terms of

personality, behaviour and mood, while viewing personality, behaviour and mood, while viewing

others as much more predictable. others as much more predictable.

Self-fulfilling prophecy - the tendency to engage Self-fulfilling prophecy - the tendency to engage

in behaviours that elicit results which will in behaviours that elicit results which will

(consciously or subconsciously) confirm our (consciously or subconsciously) confirm our

beliefs. beliefs.

Fallacies - 1Fallacies - 1 A A fallacyfallacy is a reasoning “trick” an author might is a reasoning “trick” an author might

use while trying to persuade you to accept a use while trying to persuade you to accept a

conclusion.conclusion.

Once you have identified the reasons for a Once you have identified the reasons for a

conclusion, you want to determine whether any conclusion, you want to determine whether any

fallaciesfallacies were used. If so, you will not want to were used. If so, you will not want to

accept the conclusion based on that reasoning.accept the conclusion based on that reasoning.

Thus, looking for Thus, looking for fallaciesfallacies in an important step in in an important step in

determining conclusion acceptance or rejection. determining conclusion acceptance or rejection.

http://en.wikipedia.org/wiki/Logical_fallacyhttp://en.wikipedia.org/wiki/Logical_fallacy

Fallacies - 2Fallacies - 2

Ad hominemAd hominem: An attack, or an insult, on : An attack, or an insult, on the person rather than addressing the the person rather than addressing the person’s reasoning.person’s reasoning.

Slippery slopeSlippery slope: Making the assumption : Making the assumption that a proposed step will set off an that a proposed step will set off an uncontrollable chain of undesirable events, uncontrollable chain of undesirable events, when, in fact, procedures exist to prevent when, in fact, procedures exist to prevent such a chain of events.such a chain of events.


Searching for perfect solutionsSearching for perfect solutions: Falsely : Falsely

assuming that because part of the problem assuming that because part of the problem

would remain after a solution is tried, the would remain after a solution is tried, the

solution should not be accepted.solution should not be accepted.

EquivocationEquivocation: A key word is used with two : A key word is used with two

or more meanings in an argument, such or more meanings in an argument, such

that the argument fails to make sense once that the argument fails to make sense once

the shifts in meaning are recognized.the shifts in meaning are recognized.


Appeal to popularityAppeal to popularity (ad populum): An (ad populum): An

attempt to justify a claim by appealing to attempt to justify a claim by appealing to

sentiments that large groups of people have sentiments that large groups of people have

in common; falsely assumes that anything in common; falsely assumes that anything

favoured by a large group is desireable.favoured by a large group is desireable.

Appeal to questionable authorityAppeal to questionable authority: Supporting : Supporting

a conclusion by citing an authority who lacks a conclusion by citing an authority who lacks

special expertise on the issue at hand.special expertise on the issue at hand.

Fallacies - 5Fallacies - 5 Straw personStraw person: Distorting our opponent’s point : Distorting our opponent’s point

of view so that it is easy to attack; thus we of view so that it is easy to attack; thus we

attack a point of view that does not truly exist.attack a point of view that does not truly exist.

Either-orEither-or (false dilemma): Assuming only two (false dilemma): Assuming only two

alternatives exist when it is possible that there alternatives exist when it is possible that there

are more than two.are more than two.

Wishful thinkingWishful thinking: Making the faulty assumption : Making the faulty assumption

that because we wish X were true (or false), that because we wish X were true (or false),

then X is indeed true (or false).then X is indeed true (or false).


Explaining by namingExplaining by naming: Falsely assuming : Falsely assuming

that because you have provided a name for that because you have provided a name for

some event or behaviour that you have also some event or behaviour that you have also

adequately explained the event.adequately explained the event.

Glittering generalityGlittering generality: The use of vague, : The use of vague,

emotionally appealing virtue words that emotionally appealing virtue words that

dispose us to approve something without dispose us to approve something without

closely examining the reasons.closely examining the reasons.


Red herringRed herring: An irrelevant topic is presented to : An irrelevant topic is presented to

divert attention from the original issue and divert attention from the original issue and

help to “win” an argument by shifting help to “win” an argument by shifting

attention, away from the argument and to attention, away from the argument and to

another issue.another issue.

Begging the questionBegging the question: An argument in which : An argument in which

the conclusion is assumed in the reasoning.the conclusion is assumed in the reasoning.


Hasty generalization fallacyHasty generalization fallacy: A person draws : A person draws a conclusion about a large group based on a conclusion about a large group based on experiences with only a few members of the experiences with only a few members of the group.group.

Faulty analogyFaulty analogy: Occurs when an analogy is : Occurs when an analogy is proposed in which there are important proposed in which there are important relevant dissimilarities.relevant dissimilarities.

Causal over simplificationCausal over simplification: Explaining an : Explaining an event by relying on causal factors that are event by relying on causal factors that are insufficient to account for the event or by insufficient to account for the event or by overemphasizing the role of one or more of overemphasizing the role of one or more of these factors.these factors.

Fallacies - 9Fallacies - 9 Confusion of cause and effectConfusion of cause and effect: Confusing the : Confusing the

cause with the effect of an event, or failing to cause with the effect of an event, or failing to recognize that the two may be influencing recognize that the two may be influencing each other.each other.

Neglect of a common causeNeglect of a common cause: Failure to : Failure to recognize that two events may be related recognize that two events may be related because of the effects of a common third because of the effects of a common third factor.factor.

Post hoc fallacyPost hoc fallacy: Assuming that a particular : Assuming that a particular event, B, is caused by another event, A, event, B, is caused by another event, A, simply because B follows A in time.simply because B follows A in time.

Abduction - 1Abduction - 1

Abduction, or abductive reasoning, is the , or abductive reasoning, is the

process of reasoning to the best process of reasoning to the best explanationsexplanations..

It is the reasoning process that starts from a It is the reasoning process that starts from a

set of set of observationsobservations or or conclusionsconclusions and derives and derives

their most likely explanations.their most likely explanations.

The term The term abductionabduction is sometimes used to mean is sometimes used to mean

just the generation of just the generation of hypotheseshypotheses to explain to explain

observations or conclusions, given a observations or conclusions, given a theorytheory..


DeductionDeduction and and abductionabduction differ in the differ in the

direction in which a rule like direction in which a rule like ""aa entails entails b b "" is is

used for inference:used for inference:

Deduction allows deriving Deduction allows deriving bb as a as a

consequence of consequence of a a ; i.e., deduction is the ; i.e., deduction is the

process of deriving the consequences of process of deriving the consequences of

what is known. what is known.

Abduction allows deriving Abduction allows deriving aa as an as an

explanation of explanation of bb..


Abduction works in reverse to deduction, by allowing the precondition a of ""aa entails entails b b "" to be derived from the consequence b. I.e. abduction is the process of explaining what is known.

Charles Peirce introduced abduction into logic, to mean the use of a rule or hypothetical fact to explain an observation, e.g. ""if it rains the grass is wet"" is used to explain why the grass is wet, given that it has rained, or vice-versa.


In logic, abduction is done from a logical In logic, abduction is done from a logical

theory theory TT representing a domain and a set representing a domain and a set

of observations of observations OO..

Abduction is the process of deriving a set Abduction is the process of deriving a set

of explanations of of explanations of OO according to according to TT. For . For EE

to be an explanation of to be an explanation of OO according to according to TT, it , it

should satisfy two conditions:should satisfy two conditions:

OO follows from follows from EE and and TT; ;

EE is consistent with is consistent with TT. .

Abduction - 5Abduction - 5 In formal logic, In formal logic, OO and and EE are assumed to be are assumed to be

sets of literals. The two conditions for sets of literals. The two conditions for EE being being an explanation of an explanation of OO according to theory according to theory TT are: are:

– T T ⋃⋃ E E ⊨⊨ O O ; ;

– T T ⋃⋃ E E is consistent. is consistent.

Among the possible explanations Among the possible explanations EE satisfying satisfying these two conditions, a condition of minimality these two conditions, a condition of minimality is usually imposed to avoid irrelevant facts is usually imposed to avoid irrelevant facts (not contributing to the entailment of (not contributing to the entailment of O O ) to be ) to be included in the explanations.included in the explanations.

Abduction - 6Abduction - 6 An application of abduction is that of detecting An application of abduction is that of detecting

faults in systems: given a theory relating faults faults in systems: given a theory relating faults with their effects and a set of observed effects, with their effects and a set of observed effects, abduction can be used to derive sets of faults that abduction can be used to derive sets of faults that are likely to be the cause of the problem.are likely to be the cause of the problem.

Belief revision, the process of adapting beliefs in Belief revision, the process of adapting beliefs in view of new information, is another field in which view of new information, is another field in which abduction has been applied. The main problem of abduction has been applied. The main problem of belief revision is that the new information may be belief revision is that the new information may be inconsistent with the corpus of beliefs, while the inconsistent with the corpus of beliefs, while the result of the incorporation must result of the incorporation must notnot be be inconsistent.inconsistent.

Models -1Models -1

ScientistsScientists often describe what they do as often describe what they do as

constructing constructing modelsmodels. Understanding . Understanding

scientific reasoning requires understanding scientific reasoning requires understanding

something about models and how they are something about models and how they are

used in science.used in science.

There are at least 3 kinds of models:There are at least 3 kinds of models:

– scalescale: : e.g. model airplanee.g. model airplane

– analoganalog: : e.g. conventional city mapse.g. conventional city maps

– theoreticaltheoretical: : e.g. Newtonian physics equations e.g. Newtonian physics equations

Models -2Models -2

ModelsModels need to be put in need to be put in correspondencecorrespondence with with

realityreality, through , through hypotheseshypotheses and and interpretationsinterpretations..

A model may A model may predictpredict something that is something that is not not

confirmedconfirmed, in which case the model is , in which case the model is incorrectincorrect..

A model may A model may fail to predictfail to predict something it should something it should

be able to, in which case it is be able to, in which case it is incompleteincomplete..

Like other mal-functioning Like other mal-functioning artefactsartefacts, mistaken , mistaken

models can be models can be diagnoseddiagnosed. .

Model-based diagnosis - 1Model-based diagnosis - 1

DiagnosisDiagnosis is concerned with the development of is concerned with the development of algorithms and techniques that can determine algorithms and techniques that can determine whether the whether the behaviourbehaviour of a system (or of a system (or artefactartefact) is ) is correct. The artefact may be a correct. The artefact may be a theorytheory..

If the system is not If the system is not functioningfunctioning correctly, the correctly, the algorithm should be able to determine, as algorithm should be able to determine, as accurately as possible, which part of the system accurately as possible, which part of the system is failing, and the kind of is failing, and the kind of faultfault it is facing. it is facing.

The computation is based on The computation is based on observationsobservations which which provide information on the current behaviour. provide information on the current behaviour.

Model-based diagnosis - 2Model-based diagnosis - 2 Model-based diagnosis is an example of Model-based diagnosis is an example of

abductiveabductive reasoningreasoning using a using a modelmodel of the of the system:system:

Model-based diagnosis - 3Model-based diagnosis - 3

A A modelmodel describes the behaviour of the system, or describes the behaviour of the system, or artefact. The model can itself artefact. The model can itself be be the artefact.the artefact.

It an abstraction of the It an abstraction of the behaviourbehaviour of the system of the system and can be incomplete. The and can be incomplete. The faulty behaviourfaulty behaviour may may be little-known, and the be little-known, and the fault modelfault model might not be might not be represented. If the model is a program: represented. If the model is a program: debuggingdebugging..

Given the Given the observationsobservations, the diagnoser, the diagnoser simulates simulates the system using the model, and compares the the system using the model, and compares the observations actually made to the observations observations actually made to the observations predictedpredicted by the simulation. by the simulation.

Model-based diagnosis - 4Model-based diagnosis - 4 The modelling can be expressed by the rules The modelling can be expressed by the rules

(where (where AbAb is the is the AbAbnormality predicate)normality predicate)::

If the behaviour of the system is not If the behaviour of the system is not abnormal (i.e. normal), then the internal abnormal (i.e. normal), then the internal (unobservable) behaviour will be (unobservable) behaviour will be Int1Int1 and the and the observable one observable one Obs1Obs1..

Otherwise, the internal behaviour will be Otherwise, the internal behaviour will be Int2Int2 and the observable behaviour and the observable behaviour Obs2Obs2..

Given the observations Given the observations ObsObs, the problem is to , the problem is to determine whether the system behaviour is determine whether the system behaviour is normal or not (normal or not (¬ ¬ Ab(S)Ab(S) or or Ab(S) Ab(S) ). This is an ). This is an example of example of abductive reasoningabductive reasoning..

Falsifiability - 1Falsifiability - 1

In science and philosophy of science, In science and philosophy of science,

falsifiabilityfalsifiability, , contingencycontingency, and , and defeasibilitydefeasibility

are roughly equivalent terms referring to are roughly equivalent terms referring to

the property of empirical statements that the property of empirical statements that

they must admit of logical they must admit of logical counterexamplescounterexamples..

This stands in contradistinction to formal This stands in contradistinction to formal

and mathematical statements that may be and mathematical statements that may be

tautologies, that is, universally true by dint tautologies, that is, universally true by dint

of definitions, axioms, and proofs.of definitions, axioms, and proofs.


Some philosophers and scientists, most Some philosophers and scientists, most

notably notably Karl PopperKarl Popper, have asserted that no , have asserted that no

empirical hypothesis, proposition, or theory empirical hypothesis, proposition, or theory

can be considered scientific if it does not can be considered scientific if it does not

admit the possibility of a contrary case.admit the possibility of a contrary case.

For example, the proposition For example, the proposition "all swans are "all swans are

white"white" would be falsified by observing a would be falsified by observing a

black swan, which would in turn depend on black swan, which would in turn depend on

there being a black swan somewhere in there being a black swan somewhere in

existence.existence.


A falsifiable proposition or theory must define A falsifiable proposition or theory must define

in some way what is, or will be, forbidden by in some way what is, or will be, forbidden by

that proposition or theory.that proposition or theory.

For example, the existence of a black swan is For example, the existence of a black swan is

forbidden by the proposition in question. The forbidden by the proposition in question. The

possibility in principle of observing a black possibility in principle of observing a black

swan as a counterexample to the general swan as a counterexample to the general

proposition is sufficient to qualify the proposition is sufficient to qualify the

proposition as falsifiable.proposition as falsifiable.


The falsification of statements occurs The falsification of statements occurs through through modus tollensmodus tollens, via some , via some observation.observation.

Suppose some universal statement Suppose some universal statement UU implies an observation implies an observation O O ::

U U →→ OO An observation conflicting with An observation conflicting with O O , however, , however,

is made:is made: ¬ ¬ OO

So by modus tollens:So by modus tollens:

¬ ¬ UU


It is always possible to It is always possible to revise the universal the universal statement or the existential statement so statement or the existential statement so that falsification does not occur.that falsification does not occur.

On hearing that a black swan has been On hearing that a black swan has been observed in Australia, one might introduce observed in Australia, one might introduce the the ad hocad hoc hypothesis, hypothesis, ""all swans are all swans are white except those found in Australiawhite except those found in Australia""..

The universal statement isThe universal statement is defeasible defeasible through through exceptionsexceptions. And there may be . And there may be exceptions to the exceptions.exceptions to the exceptions.

Belief Revision- 1Belief Revision- 1

Belief revisionBelief revision is the process of changing is the process of changing beliefs to take into account a new piece of beliefs to take into account a new piece of information.information.

The logical formalization of belief revision is The logical formalization of belief revision is researched in philosophy, in databases, and in researched in philosophy, in databases, and in artificial intelligence for the design of rational artificial intelligence for the design of rational agents.agents.

What makes belief revision non-trivial is that What makes belief revision non-trivial is that several different ways for performing this several different ways for performing this operation may be possible.operation may be possible.


E.g., the current knowledge includes the 3 E.g., the current knowledge includes the 3 facts “facts “AA is true is true”, “”, “BB is true is true” and “” and “if if AA and and BB are true then are true then CC is true is true”.”.

The introduction of the new information “The introduction of the new information “CC is falseis false” can be done preserving ” can be done preserving consistency only by removing at least one consistency only by removing at least one of the 3 facts. In this case, there are at least of the 3 facts. In this case, there are at least 3 different ways for performing revision.3 different ways for performing revision.

In general, there may be several different In general, there may be several different ways for changing knowledge.ways for changing knowledge.

Belief Revision- 3Belief Revision- 3 Two kinds of Two kinds of changechange are usually distinguished: are usually distinguished: Update.Update. New information is about the present, New information is about the present,

while the old beliefs refer to the past; update while the old beliefs refer to the past; update is the operation of changing the old beliefs to is the operation of changing the old beliefs to take into account the change. take into account the change.

Revision.Revision. Both the old beliefs and the new Both the old beliefs and the new information refer to the same situation; an information refer to the same situation; an inconsistency between them is explained by inconsistency between them is explained by the possibility of old information being less the possibility of old information being less reliable than the new one; revision is the reliable than the new one; revision is the process of inserting the new information into process of inserting the new information into the set of old beliefs without generating an the set of old beliefs without generating an inconsistency. inconsistency.


The main assumption of belief revision is that The main assumption of belief revision is that

of minimal change: the knowledge before and of minimal change: the knowledge before and

after the change should be as similar as after the change should be as similar as

possible.possible.

In the case of update, this principle In the case of update, this principle

formalizes the assumption of inertia.formalizes the assumption of inertia.

In the case of revision, this principle enforces In the case of revision, this principle enforces

as much information as possible to be as much information as possible to be

preserved by the change.preserved by the change.

Logic Program RevisionLogic Program Revision

The problem:The problem:– A LP represents A LP represents

consistent incomplete consistent incomplete knowledge;knowledge;

– New New factualfactual information comes.information comes.

– How to incorporate How to incorporate the new the new information?information?

The solution:The solution:– Add the new facts to Add the new facts to

the program;the program;– If the union is If the union is

consistent this is the consistent this is the result;result;

– Otherwise Otherwise restore restore consistencyconsistency to the to the union.union.

The new problem:The new problem:– How to restore consistency to an How to restore consistency to an

inconsistent program?inconsistent program?

Simple revision example - 1Simple revision example - 1P: flies(X) bird(X), not ab(X). bird(a) .

ab(X) penguin(X).

SoSo flies(a) is true. Next, we learnis true. Next, we learn penguin(a).. P {penguin(a)} is consistent,is consistent, flies(a) is is false,false, not ab(a) isis defeated. Nothing needs to . Nothing needs to be done.be done. We learn insteadWe learn instead ¬flies(a).. flies(a) isis rebutted.

P {¬flies(a)} is inconsistent. What to do?is inconsistent. What to do?

Since the inconsistency rests on the Since the inconsistency rests on the assumptionassumption not ab(a), revise that assumption, , revise that assumption, e.g. by adding the facte.g. by adding the fact ab(a), thereby , thereby obtaining a new programobtaining a new program P’..

Simple revision example - Simple revision example - 22

P: flies(X) bird(X), not ab(X). bird(a) .

ab(X) penguin(X).

If an assumption supports contradiction, If an assumption supports contradiction, then go back on that assumption: the then go back on that assumption: the Reductio ad absurdumReductio ad absurdum principle. principle.

Later we learnLater we learn flies(a). P’ {flies(a)} is is inconsistent.inconsistent.

The contradiction does not depend on The contradiction does not depend on assumptions.assumptions.

Cannot remove contradiction!Cannot remove contradiction!

Some programs are non-revisable:Some programs are non-revisable:

Which assumptions remove?Which assumptions remove?

normalWheel not flatTyre, not brokenSpokes.

flatTyre leakyValve.

¬ normalWheel wobblyWheel.

flatTyre puncturedTube. wobblyWheel .

Contradiction can be removed by either revisingContradiction can be removed by either revising not flatTyre oror not brokenSpokes ((or both).or both).

We’d like to delve deeper into the model and, We’d like to delve deeper into the model and, instead ofinstead of not flatTyre, revise either , revise either

not leakyValve or or not puncturedTube ((or both).or both).

RevisablesRevisables

not {leakyValve, punctureTube, brokenSpokes}

Revisions in this case are:Revisions in this case are:

{not lv},, {not pt},, and and {not bs}

Solution: define a set ofSolution: define a set of revisables

normalWheel not flatTyre, not brokenSpokes.

flatTyre leakyValve.

¬ normalWheel wobblyWheel.

flatTyre puncturedTube. wobblyWheel .

Integrity ConstraintsIntegrity Constraints

For convenience, instead of:For convenience, instead of:

¬ normalWheel wobblyWheel

we may use the denial:we may use the denial:

normalWheel, wobblyWheel

Example - 1Example - 1

Rev =Rev = not {a,b,c}

p, q

p not a.

q not b, r.

r not b.

r not c.

p q

not a r not b

not b not c

Support sets are:Support sets are:{not a, not b}andand {not a, not b, not c}..

Removal sets are:Removal sets are: {not a} andand {not b}..

Example - 2Example - 2

In 2-valued revision:In 2-valued revision:– some removals must be deleted;some removals must be deleted;– the process must be iterated.the process must be iterated.

p. a. b, not c.p not a, not b.

a

X

p

not a not bb not c

XThe only support isThe only support is {not a, not b}..Removals areRemovals are {not a} andand {not b}..

• P U {a} is contradictory (and unrevisable).is contradictory (and unrevisable).• P U {b} is contradictory (though revisable).is contradictory (though revisable).

But:But:

Revision and DiagnosisRevision and Diagnosis In model based diagnosis one has:In model based diagnosis one has:

– A programA program P with the model of a system, with with the model of a system, with

the correct and, possibly, the incorrect the correct and, possibly, the incorrect

behaviours.behaviours.

– A set of observationsA set of observations O inconsistent withinconsistent with P , or , or

not explained bynot explained by P ..

The diagnoses of the system are the revisions ofThe diagnoses of the system are the revisions of

P U O


Naïve falsificationNaïve falsification considers scientific considers scientific statements individually. But scientific statements individually. But scientific theoriestheories are formed from groups of these sorts of are formed from groups of these sorts of statements, and it is these groups that must be statements, and it is these groups that must be accepted or rejected by scientists. Scientific accepted or rejected by scientists. Scientific theories can always be defended by the theories can always be defended by the addition of addition of ad hocad hoc hypotheseshypotheses..

As Popper put it, a As Popper put it, a decision is required on the is required on the part of the scientist to part of the scientist to acceptaccept or or rejectreject the the statementsstatements that go to make up a theory or that that go to make up a theory or that might falsify it.might falsify it.

Falsifiability - 7Falsifiability - 7 At some point, the weight of the At some point, the weight of the ad hocad hoc

hypotheses and hypotheses and disregardeddisregarded falsifying falsifying observationsobservations will become so great that it becomes will become so great that it becomes unreasonableunreasonable to support the base theory any longer, and a to support the base theory any longer, and a decision will be made to reject it.decision will be made to reject it.

In place of naïve falsification, Popper envisioned In place of naïve falsification, Popper envisioned science as evolving by the successive rejection of science as evolving by the successive rejection of falsified theories, rather than falsified statements.falsified theories, rather than falsified statements.

Falsified theories are to be replaced by theories Falsified theories are to be replaced by theories that account for the phenomena which falsified the that account for the phenomena which falsified the prior theory, i.e. with greater prior theory, i.e. with greater explanatory powerexplanatory power. .

Falsifiability - 8Falsifiability - 8 PopperPopper proposed falsification as a way to proposed falsification as a way to

determine if a theory is scientific. If a theory is determine if a theory is scientific. If a theory is falsifiable, then it is scientific; if it is not, then it is falsifiable, then it is scientific; if it is not, then it is not science. A theory not open to falsification not science. A theory not open to falsification requires requires faithfaith that it is not false. He uses this that it is not false. He uses this criterion of demarcationcriterion of demarcation to draw a sharp line to draw a sharp line between scientific and unscientific theories.between scientific and unscientific theories.

Falsifiability was one of the criteria used by Judge Falsifiability was one of the criteria used by Judge Overton to determine that Overton to determine that 'creation science''creation science' was was not scientific and should not be taught in public not scientific and should not be taught in public schools. It was enshrined in United States law for schools. It was enshrined in United States law for whether scientific whether scientific evidenceevidence is is admissibleadmissible in a jury in a jury trial. trial.

Scientific method - 1Scientific method - 1 Scientific methodScientific method is a body of techniques for is a body of techniques for

investigating phenomena and acquiring new investigating phenomena and acquiring new knowledge, as well as for correcting and knowledge, as well as for correcting and integrating previous knowledge. It is based integrating previous knowledge. It is based on observable, empirical, measurable on observable, empirical, measurable evidence, and subject to laws of reasoning.evidence, and subject to laws of reasoning.

Although specialized procedures vary from Although specialized procedures vary from one field of inquiry to another, there are one field of inquiry to another, there are identifiable features that distinguish identifiable features that distinguish scientific inquiry from other methods of scientific inquiry from other methods of developing knowledge.developing knowledge.

Scientific method - 2Scientific method - 2

Scientific researchers propose Scientific researchers propose specificspecific hypotheses as hypotheses as explanationsexplanations of natural of natural phenomena, and design phenomena, and design experimentalexperimental studies studies that test these that test these predictionspredictions for accuracy. for accuracy.

These steps are These steps are repeatedrepeated in order to make in order to make increasingly increasingly dependabledependable predictions of future predictions of future results. results.

TheoriesTheories that encompass whole domains of that encompass whole domains of inquiry serve to bind more specific inquiry serve to bind more specific hypotheses together into logically hypotheses together into logically coherentcoherent wholes. wholes.


This in turn aids in the This in turn aids in the formationformation of new of new hypotheseshypotheses, as well as in placing groups of , as well as in placing groups of specific hypotheses into a broader specific hypotheses into a broader contextcontext of understanding.of understanding.

Among other facets shared by the various Among other facets shared by the various fields of inquiry is the conviction that the fields of inquiry is the conviction that the process must be process must be objectiveobjective so that the so that the scientist does not scientist does not biasbias the the interpretationinterpretation of of the results or change the results outright. the results or change the results outright.


Another basic expectation is that of Another basic expectation is that of making complete making complete documentationdocumentation of data of data and and methodologymethodology available for careful available for careful scrutinyscrutiny by other scientists and by other scientists and researchers, thereby allowing other researchers, thereby allowing other researchers the opportunity to researchers the opportunity to verifyverify results by attempted results by attempted reproductionreproduction of them. of them.

This also allows This also allows statistical measuresstatistical measures of the of the reliabilityreliability of the results to be established. of the results to be established.


There are multiple ways of outlining the There are multiple ways of outlining the basic basic

methodmethod shared by all of the fields of shared by all of the fields of scientificscientific

inquiryinquiry..

The following The following facetsfacets are typical classifications are typical classifications

of the most important of the most important componentscomponents of the of the

methodmethod on which there is very wide on which there is very wide

agreementagreement in the scientific in the scientific communitycommunity and and

among philosophers of science.among philosophers of science.


ObservationObservation. A constant feature of scientific . A constant feature of scientific inquiry. inquiry.

DescriptionDescription. Information must be reliable, . Information must be reliable, i.e., replicable (repeatable) as well as valid i.e., replicable (repeatable) as well as valid (relevant to the inquiry). (relevant to the inquiry).

PredictionPrediction. Information must be valid for . Information must be valid for observations past, present, and future of observations past, present, and future of given phenomena, i.e., purported "one shot" given phenomena, i.e., purported "one shot" phenomena do not give rise to the phenomena do not give rise to the capability to predict, nor to the ability to capability to predict, nor to the ability to repeat an experiment. repeat an experiment.


ControlControl. Actively and fairly sampling the range . Actively and fairly sampling the range of of possiblepossible occurrences, whenever possible and occurrences, whenever possible and proper, as opposed to the passive acceptance proper, as opposed to the passive acceptance of opportunistic data, is the best way to control of opportunistic data, is the best way to control or counterbalance the risk of empirical bias. or counterbalance the risk of empirical bias.

FalsifiabilityFalsifiability, or the elimination of plausible , or the elimination of plausible alternatives. This is a gradual process that alternatives. This is a gradual process that requires repeated experiments by multiple requires repeated experiments by multiple researchers who must be able to replicate researchers who must be able to replicate results in order to corroborate them.results in order to corroborate them.


All hypotheses and theories are in principle All hypotheses and theories are in principle

subject to disproof.subject to disproof. There might be a There might be a

consensus about a particular hypothesis or consensus about a particular hypothesis or

theory, yet it must in principle remain theory, yet it must in principle remain

tentative. tentative.

As a body of knowledge grows and a As a body of knowledge grows and a

particular hypothesis or theory repeatedly particular hypothesis or theory repeatedly

brings brings predictablepredictable results, results, confidenceconfidence in the in the

hypothesis or theory increases.hypothesis or theory increases.


Causal explanationCausal explanation. The following . The following requirements are generally regarded as requirements are generally regarded as important to scientific understanding: important to scientific understanding:

– Identification of causesIdentification of causes. Identification of the . Identification of the causes of a particular phenomenon to the causes of a particular phenomenon to the best achievable extent. best achievable extent.

– Covariation of eventsCovariation of events. The hypothesized . The hypothesized causes must correlate with observed effects. causes must correlate with observed effects.

– Time-order relationshipTime-order relationship. The hypothesized . The hypothesized causes must precede the observed effects.causes must precede the observed effects.

Scientific method - 10Scientific method - 10 TestabilityTestability, a property applying to an empirical , a property applying to an empirical

hypothesis, involves two components:hypothesis, involves two components: The logical property described as contingency, The logical property described as contingency,

defeasibility, or defeasibility, or falsifiabilityfalsifiability, meaning that , meaning that counterexamples to the hypothesis are not counterexamples to the hypothesis are not logically impossible.logically impossible.

The practical The practical feasibilityfeasibility of observing a of observing a reproducible series of such counterexamples, if reproducible series of such counterexamples, if they do exist.they do exist.

In short, a hypothesis is testable if there is some In short, a hypothesis is testable if there is some real hope of deciding whether it is true or false real hope of deciding whether it is true or false of real of real experienceexperience. .

Scientific method - 11Scientific method - 11 The The predictive powerpredictive power of a scientific theory of a scientific theory

refers to its ability to generate refers to its ability to generate testabletestable predictions. predictions.

TheoriesTheories with strong predictive power are with strong predictive power are highly valued, because the predictions can highly valued, because the predictions can often encourage the falsification of the theory.often encourage the falsification of the theory.

The concept of predictive power differs from The concept of predictive power differs from explanatory or explanatory or descriptive powerdescriptive power (where (where phenomena that are already known are phenomena that are already known are retrospectively explained by a given theory) in retrospectively explained by a given theory) in that it allows a that it allows a prospectiveprospective test of theoretical test of theoretical understanding.understanding.


Scientific ideas that do not confer any Scientific ideas that do not confer any predictive power are considered at best predictive power are considered at best ""conjecturesconjectures", or at worst "", or at worst "pseudosciencepseudoscience". ". Because they cannot be tested or falsified in Because they cannot be tested or falsified in any way, there is no way to determine any way, there is no way to determine whether they are true or false, and so they do whether they are true or false, and so they do not gain the status of "not gain the status of "scientific theoryscientific theory".".

Theories whose "Theories whose "predictive powerpredictive power" " presupposes technologies that are not presupposes technologies that are not currently possible constitute something of a currently possible constitute something of a grey area.grey area.


ReproducibilityReproducibility is one of the main principles is one of the main principles

of the of the scientific methodscientific method, and refers to the , and refers to the

ability of a ability of a testtest or experiment to be or experiment to be

accurately reproduced, or accurately reproduced, or replicatedreplicated..

The term is very closely related to the The term is very closely related to the

concept of concept of testabilitytestability and, depending on and, depending on

the particular field, may require the test or the particular field, may require the test or

experiment to be experiment to be falsifiablefalsifiable..

Scientific method - 14Scientific method - 14 The results of an The results of an experimentexperiment performed by a performed by a

group of researchers are generally evaluated group of researchers are generally evaluated by other by other independentindependent researchers by researchers by reproducing the original experiment.reproducing the original experiment.

They They repeatrepeat the same experiment themselves, the same experiment themselves, based on the original experimental based on the original experimental descriptiondescription, , and see if their experiment gives and see if their experiment gives similar resultssimilar results to those to those reportedreported by the original group. by the original group.

The result values are said to be The result values are said to be commensuratecommensurate if they are obtained (in distinct experimental if they are obtained (in distinct experimental trials) according to the same trials) according to the same reproduciblereproducible experimental description and procedure.experimental description and procedure.


Experiments which cannot be Experiments which cannot be reliablyreliably

reproducedreproduced are generally not considered to are generally not considered to

provide useful provide useful scientific evidencescientific evidence..

ResultsResults which prove to be which prove to be highlyhighly

reproduciblereproducible are given are given moremore credencecredence than than

those which are less reproducible, although those which are less reproducible, although

this is based on an intuitive application of the this is based on an intuitive application of the

principle of inductionprinciple of induction, rather than on the , rather than on the

strict application of the principles of strict application of the principles of

falsifiability.falsifiability.

Science features – summary Science features – summary 11

ScienceScience is the organized, is the organized, systematicsystematic

enterprize that gathers enterprize that gathers knowledgeknowledge about the about the

worldworld and our theorizations and condenses it and our theorizations and condenses it

into into testabletestable lawslaws and and principlesprinciples..

The The featuresfeatures of science that distinguish it of science that distinguish it

from pseudoscience are: from pseudoscience are: repeatability, repeatability,

economy, mensuration, heuristics, economy, mensuration, heuristics,

consilienceconsilience..


RepeatabilityRepeatability: The same phenomenon is : The same phenomenon is sought again, preferably by sought again, preferably by independentindependent investigation, and the interpretation given investigation, and the interpretation given to it is to it is confirmedconfirmed or or discardeddiscarded by means of by means of novel novel analysisanalysis and and experimentationexperimentation..

EconomyEconomy: Scientists attempt to : Scientists attempt to abstractabstract the information into the form that is both the information into the form that is both simplestsimplest and aesthetically most pleasing – and aesthetically most pleasing – the combination called the combination called eleganceelegance – while – while yielding the yielding the largestlargest amount of information amount of information with the with the leastleast amount of amount of efforteffort..


MensurationMensuration: If something come be properly : If something come be properly

measured, using measured, using universallyuniversally acceptedaccepted scalesscales, ,

generalizations about it are rendered generalizations about it are rendered unambiguousunambiguous..

HeuristicsHeuristics: The best science : The best science stimulatesstimulates further further

discoverydiscovery, often in unpredictable , often in unpredictable new directionsnew directions; ;

and the new knowledge provides an and the new knowledge provides an additional testadditional test

of the original principles that led to its discovery.of the original principles that led to its discovery.

ConsilienceConsilience: The : The explanationsexplanations most likely to survive most likely to survive

of different phenomena are those that can be of different phenomena are those that can be

connectedconnected and proved and proved consistentconsistent with one another. with one another.

Epistemology - 1Epistemology - 1 EpistemologyEpistemology (or (or theory of knowledgetheory of knowledge) is a branch ) is a branch

of philosophy studying the nature and scope of of philosophy studying the nature and scope of knowledge. From the Greek words knowledge. From the Greek words epistemeepisteme (knowledge) and (knowledge) and logoslogos (account). (account).

It focuses on analyzing the nature of knowledge It focuses on analyzing the nature of knowledge and how it relates to notions such as and how it relates to notions such as truthtruth, , beliefbelief, , and and justificationjustification..

It also deals with the means of It also deals with the means of productionproduction of of knowledgeknowledge, and , and skepticismskepticism about knowledge about knowledge claims.claims.

It addresses the questions: "It addresses the questions: "What is knowledgeWhat is knowledge?", ?", ""How is it acquiredHow is it acquired?", and "?", and "What do people knowWhat do people know?"?"

Epistemology - 2Epistemology - 2 In epistemology, the kind of knowledge usually In epistemology, the kind of knowledge usually

discussed is discussed is propositional knowledgepropositional knowledge, also , also known as "known as "knowledge-thatknowledge-that", as opposed to ", as opposed to ""know-howknow-how".".

To exemplify: in mathematics, there is To exemplify: in mathematics, there is knowingknowing thatthat 2 + 2 = 4, but there is also 2 + 2 = 4, but there is also knowingknowing howhow to to count to 4. Or, one knows count to 4. Or, one knows howhow to ride a bicycle to ride a bicycle and one knows and one knows thatthat a bicycle has two wheels. a bicycle has two wheels.

The distinction is between The distinction is between theoretical reasontheoretical reason and and practical reasonpractical reason, with epistemology being , with epistemology being interested in knowledge of the theoretical kind, interested in knowledge of the theoretical kind, not the practical kind.not the practical kind.

Epistemology - 3Epistemology - 3

Sometimes, when people say that they Sometimes, when people say that they believebelieve in something, what they mean is in something, what they mean is that they that they predictpredict that it will prove to be that it will prove to be usefuluseful or or successfulsuccessful in some sense -- in some sense -- perhaps someone might "believe in" his perhaps someone might "believe in" his favorite football team.favorite football team.

This is not the kind of belief usually dealt This is not the kind of belief usually dealt with in with in epistemologyepistemology. The kind that . The kind that isis dealt dealt with is that where "with is that where "to believe somethingto believe something" " just means to think that just means to think that it is trueit is true -- e.g., to -- e.g., to believe that the sky is blue is to think that believe that the sky is blue is to think that the proposition "The sky is blue" is true.the proposition "The sky is blue" is true.

Epistemology - 4Epistemology - 4 Belief is a part of knowledgeBelief is a part of knowledge. Consider . Consider

someone saying, "I know that someone saying, "I know that PP is true, but I is true, but I don't believe that don't believe that PP is true." Persons making is true." Persons making this utterance, it seems, contradict this utterance, it seems, contradict themselves. If one knows themselves. If one knows PP, then, among , then, among other things, one thinks that other things, one thinks that PP is indeed true. is indeed true. If one thinks that If one thinks that PP is true, then one believes is true, then one believes PP. .

Knowledge is distinct from beliefKnowledge is distinct from belief. If someone . If someone claims to believe something, he is claiming claims to believe something, he is claiming that it is the truth. Of course, it might turn out that it is the truth. Of course, it might turn out that he or she was mistaken, and that what that he or she was mistaken, and that what was thought to be true was actually false. This was thought to be true was actually false. This is not the case with knowledge.is not the case with knowledge.

Epistemology - 5Epistemology - 5 Suppose Jeff thinks a particular bridge is Suppose Jeff thinks a particular bridge is

safe, and attempts to cross it, but the bridge safe, and attempts to cross it, but the bridge collapses under his weight. We might say Jeff collapses under his weight. We might say Jeff believedbelieved that the bridge was safe, but that that the bridge was safe, but that his belief was mistaken.his belief was mistaken.

We would We would notnot (accurately) say that he (accurately) say that he knewknew that the bridge was safe, because plainly it that the bridge was safe, because plainly it was not.was not.

For something to count as knowledge it must For something to count as knowledge it must be true.be true.

Epistemology - 6Epistemology - 6 According to the theory that According to the theory that knowledge is justified knowledge is justified

true belieftrue belief, in order to know that a given , in order to know that a given proposition is true, one must not only believe the proposition is true, one must not only believe the relevant true proposition, but one must also have a relevant true proposition, but one must also have a good reasongood reason for doing so. for doing so.

One implication of this would be that no one would One implication of this would be that no one would gain knowledge just by believing something that gain knowledge just by believing something that happened to be true.happened to be true.

An ill person with no medical training but an An ill person with no medical training but an optimistic attitude, might believe that she will optimistic attitude, might believe that she will recover from her illness quickly. However, even if recover from her illness quickly. However, even if this belief turned out to be true, the patient would this belief turned out to be true, the patient would not have not have knownknown that she would get well, since her that she would get well, since her belief lacked justificationbelief lacked justification. .

Philosophy of science - 1Philosophy of science - 1

Philosophy of sciencePhilosophy of science is a branch of philosophy is a branch of philosophy

studying the philosophical studying the philosophical assumptionsassumptions, ,

foundationsfoundations, and , and implicationsimplications of science, of science,

including the formal, natural, and social sciences.including the formal, natural, and social sciences.

It is closely related to It is closely related to epistemologyepistemology and the and the

philosophy of languagephilosophy of language..

Issues of scientific Issues of scientific ethicsethics are are notnot considered to considered to

be part of the philosophy of science; they are be part of the philosophy of science; they are

studied in such fields as bioethics and science studied in such fields as bioethics and science

studies.studies.


The The philosophy of sciencephilosophy of science tackles the tackles the topicstopics::

– The character and the development of The character and the development of

concepts and terms, propositions and concepts and terms, propositions and

hypotheses, arguments and conclusions, as hypotheses, arguments and conclusions, as

they function in science. they function in science.

– The manner in which science explains The manner in which science explains

natural phenomena and predicts natural natural phenomena and predicts natural

occurrences. occurrences.

– The types of reasoning that are used to The types of reasoning that are used to

arrive at scientific conclusions. arrive at scientific conclusions.


– The formulation, scope, and limits of The formulation, scope, and limits of

scientific method. scientific method.

– The means that should be used for The means that should be used for

determining the validity of scientific determining the validity of scientific

information, in other words, the question of information, in other words, the question of

objectivity. objectivity.

– The implications of scientific methods and The implications of scientific methods and

models, along with the technology that arises models, along with the technology that arises

from scientific knowledge, for the larger from scientific knowledge, for the larger

society. society.

Evolutionary Psychology Evolutionary Psychology and the Unity of Sciencesand the Unity of Sciences

– towards an evolutionary – towards an evolutionary epistemologyepistemology

Luís Moniz PereiraLuís Moniz Pereira

Centro de Inteligência Artificial – CENTRIACentro de Inteligência Artificial – CENTRIAUniversidade Nova de Lisboa – UNLUniversidade Nova de Lisboa – UNL

Evolutionary Psychology and the Unity of Sciences Evolutionary Psychology and the Unity of Sciences – towards an evolutionary epistemology– towards an evolutionary epistemologyFirst Lisbon Colloquium for the Philosophy of Sciences - Unity of Sciences, Non-Traditional First Lisbon Colloquium for the Philosophy of Sciences - Unity of Sciences, Non-Traditional

ApproachesApproaches Lisbon, 25-28 October 2006Lisbon, 25-28 October 2006

Philosophy of science - Philosophy of science - exampleexample

AbstractAbstract This work concerns a non-traditional approach to the unity of sciences, This work concerns a non-traditional approach to the unity of sciences,

based on a challenging, albeit conjectural, articulation of views based on a challenging, albeit conjectural, articulation of views

proceeding from Evolutionary Psychology and Biology, non monotonic proceeding from Evolutionary Psychology and Biology, non monotonic

and decision Logics, and Artificial Intelligence.and decision Logics, and Artificial Intelligence.

The resulting amalgam sets forth a consilience stance, wherefore the The resulting amalgam sets forth a consilience stance, wherefore the

unity of science is heuristically presupposed by means of a set of unity of science is heuristically presupposed by means of a set of

pragmatic and productive default assumptions. It is by virtue of them pragmatic and productive default assumptions. It is by virtue of them

that we conduct scientific inquiry, the consilience arising from a that we conduct scientific inquiry, the consilience arising from a

presumed unity of objective reality, itself of a heuristic and pragmatic presumed unity of objective reality, itself of a heuristic and pragmatic

conception.conception.

The attending hinges to Artificial Intelligence inevitably suggest the The attending hinges to Artificial Intelligence inevitably suggest the

emergence of an innovative symbiotic form of evolutionary emergence of an innovative symbiotic form of evolutionary

epistemology.epistemology.

ConsilienceConsilience

Arguments in favour of the unity of knowledge have been Arguments in favour of the unity of knowledge have been

strongly put by Edward Wilson, a creator of sociobiology, strongly put by Edward Wilson, a creator of sociobiology,

and author of and author of Consilience – The Unity of KnowledgeConsilience – The Unity of Knowledge

(1998). He postulates there is a single physical nature, (1998). He postulates there is a single physical nature,

and one not persuadable through argumentation. Science and one not persuadable through argumentation. Science

is not mere convention.is not mere convention.

Consilience is the result of co-evolution involving Consilience is the result of co-evolution involving

(cultural) memes and genes (see below). Our cultural (cultural) memes and genes (see below). Our cultural

memes have a genetic basis and cannot, in the long run, memes have a genetic basis and cannot, in the long run,

stand against the genes who guarantee their survival, stand against the genes who guarantee their survival,

although such attempts may potentially exist – viz. although such attempts may potentially exist – viz.

through genetic manipulation.through genetic manipulation.

Evolution and the BrainEvolution and the Brain The first bipedal primates establish the separation between The first bipedal primates establish the separation between

the human species and the other simians. To fathom the the human species and the other simians. To fathom the

abilities of the human brain it is necessary to understand what abilities of the human brain it is necessary to understand what

exactly were the problems our ancestor primates were trying exactly were the problems our ancestor primates were trying

to solve that led them to develop such an extraordinarily to solve that led them to develop such an extraordinarily

intricate brain. intricate brain.

We cannot look at the modern human brain, and its ability to We cannot look at the modern human brain, and its ability to

create science, as if the millions of evolution-years which create science, as if the millions of evolution-years which

attuned it to its present configuration had never taken place. attuned it to its present configuration had never taken place.

Among the eventual problems we have those of status, Among the eventual problems we have those of status,

territorialism, mating, gregariousness, altruism vs. territorialism, mating, gregariousness, altruism vs.

opportunism, building of artefacts, and the mappings of the opportunism, building of artefacts, and the mappings of the

external world.external world.

Evolutionary PscychologyEvolutionary Pscychology Evolutionary Psychology is a consummate example of Evolutionary Psychology is a consummate example of

successful ongoing scientific unification, engendered by a successful ongoing scientific unification, engendered by a

deeply significant combination of Psychology, Anthropology, deeply significant combination of Psychology, Anthropology,

Archaeology, Evolutionary Biology, Linguistics, Neurosciences, Archaeology, Evolutionary Biology, Linguistics, Neurosciences,

and Artificial Intelligence (David M. Buss, 2005).and Artificial Intelligence (David M. Buss, 2005).

Evolutionary Psychology has been studying the brain from the Evolutionary Psychology has been studying the brain from the

evolutionary perspective, thereby originating some extremely evolutionary perspective, thereby originating some extremely

relevant contributions. In that perspective, it has been relevant contributions. In that perspective, it has been

strongly supported by Anthropological Archaeology in its strongly supported by Anthropological Archaeology in its

empirical study of the cultural evolution of mankind (Stephen empirical study of the cultural evolution of mankind (Stephen

Shennan, 2002).Shennan, 2002).

Genes and MemesGenes and Memes In human life, we have two reproductive mechanisms: one is In human life, we have two reproductive mechanisms: one is

sexual reproduction, in which the replication unit is the sexual reproduction, in which the replication unit is the

gene; the other is mental reproduction.gene; the other is mental reproduction.

Authors from Evolutionary Psychology have construed the Authors from Evolutionary Psychology have construed the

notion of “meme”, in complement and contrast to the gene. notion of “meme”, in complement and contrast to the gene.

A meme is that which substantiates a second reproductive A meme is that which substantiates a second reproductive

system executed in the brain; the mental unit corresponding system executed in the brain; the mental unit corresponding

to the gene.to the gene.

Memes gather in assemblies, in patterns, similar to the way Memes gather in assemblies, in patterns, similar to the way

genes gather in chromosomes. Memes are patterned by genes gather in chromosomes. Memes are patterned by

ideologies, religions, and common sense ideas. Certain ideologies, religions, and common sense ideas. Certain

memes work well together, mutually reinforcing each other, memes work well together, mutually reinforcing each other,

others not, so that correcting mechanisms may be triggered.others not, so that correcting mechanisms may be triggered.

Science MemesScience Memes In this view, scientific thought emerges from distributed In this view, scientific thought emerges from distributed

personal interaction, albeit it at a spacial and temporal personal interaction, albeit it at a spacial and temporal

distance, and never in an isolated way. It must be erected distance, and never in an isolated way. It must be erected

from several confluences, or in teams, as is the case in from several confluences, or in teams, as is the case in

science. In truth, knowledge is not constructed in an science. In truth, knowledge is not constructed in an

autonomous way; rather it is engendered by networks of autonomous way; rather it is engendered by networks of

people, and processed in appropriate environments, one people, and processed in appropriate environments, one

being education, in which we carry out being education, in which we carry out memeticmemetic

proliferation.proliferation.

Language is the instrument with which to fabricate Language is the instrument with which to fabricate

knowledge together. We go so far as to state that there is knowledge together. We go so far as to state that there is

no isolated consciousness, that all consciousness is no isolated consciousness, that all consciousness is

distributed. When we consider consciousness we should distributed. When we consider consciousness we should

take it out of the brain and spread it through culture; this take it out of the brain and spread it through culture; this

is the importance of language.is the importance of language.

ArchaeologyArchaeology Theoretical and field archaeologists, cf. Steven Mithen in Theoretical and field archaeologists, cf. Steven Mithen in

The Prehistory of Mind The Prehistory of Mind (1996), are bringing in historical and (1996), are bringing in historical and pre-historical evidence that our ancestors began with a pre-historical evidence that our ancestors began with a generic intelligence, such as we find in apes.generic intelligence, such as we find in apes.

There has been a broad discussion – reproduced within the There has been a broad discussion – reproduced within the Artificial Intelligence (AI) community – about whether Artificial Intelligence (AI) community – about whether intelligence is a general functionality or else best envisaged intelligence is a general functionality or else best envisaged as divided into specific ability modules or components. as divided into specific ability modules or components.

Archaeologists have come to demonstrate, through their Archaeologists have come to demonstrate, through their records, the human species went from a first phase of a records, the human species went from a first phase of a simple general intelligence to a second phase of three major simple general intelligence to a second phase of three major specialized modules: one for natural history and naive specialized modules: one for natural history and naive physics - physics - Knowledge of NatureKnowledge of Nature; one for ; one for Knowledge and Knowledge and Manufacture of InstrumentsManufacture of Instruments; and one for ; and one for Cultural ArtefactsCultural Artefacts, , i.e. the rules of living in society and the very politics of i.e. the rules of living in society and the very politics of coexistence.coexistence.

Specialized Modules and General Specialized Modules and General CupolaCupola

These three specialized intelligences were separately These three specialized intelligences were separately

developed and uncommunicating, and it is only at a newer developed and uncommunicating, and it is only at a newer

stage – corresponding to stage – corresponding to Homo SapiensHomo Sapiens, and the appearance , and the appearance

of spoken language – that it becomes necessary to have a of spoken language – that it becomes necessary to have a

cupola module, articulating the specific ones. How else do the cupola module, articulating the specific ones. How else do the

different specialized modules connect, and how can people - different specialized modules connect, and how can people -

as module envelopes - communicate among themselves?as module envelopes - communicate among themselves?

That need gave birth to the generic cupola module, a much That need gave birth to the generic cupola module, a much

more sophisticated form of general intelligence, the cognitive more sophisticated form of general intelligence, the cognitive

glue bringing the specialized modules to communicate and glue bringing the specialized modules to communicate and

cooperate.cooperate.

The Evolution of Reason: LogicThe Evolution of Reason: Logic The formal systems of logic have ordinarily been regarded The formal systems of logic have ordinarily been regarded

as independent of biology, but recent developments in as independent of biology, but recent developments in evolutionary theory suggest that biology and logic may be evolutionary theory suggest that biology and logic may be intimately interrelated. William S. Cooper (2001) outlines a intimately interrelated. William S. Cooper (2001) outlines a theory of rationality in which logical law emerges as an theory of rationality in which logical law emerges as an intrinsic aspect of evolutionary biology.intrinsic aspect of evolutionary biology.

This biological perspective on logic, though at present This biological perspective on logic, though at present unorthodox, could change traditional ideas about the unorthodox, could change traditional ideas about the reasoning process. Cooper examines the connections reasoning process. Cooper examines the connections between logic and evolutionary biology and illustrates how between logic and evolutionary biology and illustrates how logical rules are derived directly from evolutionary logical rules are derived directly from evolutionary principles, and therefore have no independent status of their principles, and therefore have no independent status of their own.own.

Laws of decision theory, utility theory, induction, and Laws of decision theory, utility theory, induction, and deduction are reinterpreted as natural consequences of deduction are reinterpreted as natural consequences of evolutionary processes. Cooper's connection of logical law to evolutionary processes. Cooper's connection of logical law to evolutionary theory ultimately results in a unified foundation evolutionary theory ultimately results in a unified foundation for an evolutionary science of reason.for an evolutionary science of reason.

Behaviour and the Logic of DecisionBehaviour and the Logic of Decision Decision theory is the branch of logic that comes into most Decision theory is the branch of logic that comes into most

immediate contact with the concerns of evolutionary biology. immediate contact with the concerns of evolutionary biology. They are bound together by virtue of their mutual They are bound together by virtue of their mutual involvement in behaviour. The logic of decision is concerned involvement in behaviour. The logic of decision is concerned with choices regarding the most reasonable courses of action, with choices regarding the most reasonable courses of action, or behavioural patterns.or behavioural patterns.

Behaviour is observable, it is amenable to scientific prediction Behaviour is observable, it is amenable to scientific prediction and explanation, and there is the possibility of explaining it in and explanation, and there is the possibility of explaining it in evolutionary terms. This makes behaviour an interdisciplinary evolutionary terms. This makes behaviour an interdisciplinary bridge approachable from both the biological and the logical bridge approachable from both the biological and the logical sides.sides.

Ultimately, behaviour is the fulcrum over which evolutionary Ultimately, behaviour is the fulcrum over which evolutionary forces extend their leverage into the realm of logic. Viewed forces extend their leverage into the realm of logic. Viewed through the lenses of biology, favoured behaviour is through the lenses of biology, favoured behaviour is evolutionary fit. Through the lens of logic it is rational decision evolutionary fit. Through the lens of logic it is rational decision behaviour (Cooper, 2001), according to rules for reasoning behaviour (Cooper, 2001), according to rules for reasoning and rules for action.and rules for action.

Games, Logic and CommunicationGames, Logic and Communication On the heels of rational group behaviour, throughout human On the heels of rational group behaviour, throughout human

cultures there emerged abstract rule following social games. cultures there emerged abstract rule following social games. Game rules encapsulate concrete situation defining patterns, Game rules encapsulate concrete situation defining patterns, and concrete situation-action-situation causal sequencing, and concrete situation-action-situation causal sequencing, which mirrors causality-obeying physical reality. which mirrors causality-obeying physical reality.

From games, further abstraction ensued, and there finally From games, further abstraction ensued, and there finally emerged the notions of situation-defining concepts, of emerged the notions of situation-defining concepts, of general rules of thought and their chaining, and of legitimate general rules of thought and their chaining, and of legitimate argument and counter-argument moves. Together they argument and counter-argument moves. Together they compose a cognitive meta-game (John Holland, 1998).compose a cognitive meta-game (John Holland, 1998).

The pervasiveness of informal logic for capturing knowledge The pervasiveness of informal logic for capturing knowledge and for reasoning, a veritable and for reasoning, a veritable lingua francalingua franca across human across human languages and cultures, rests on its ability to actually foster languages and cultures, rests on its ability to actually foster rational understanding and common objectivity. Objective rational understanding and common objectivity. Objective knowledge evolution dynamics, whether individual or plural, knowledge evolution dynamics, whether individual or plural, follows ratiocination patterns and laws.follows ratiocination patterns and laws.

The Cupola of LogicThe Cupola of Logic Logic, we sustain, provides the overall conceptual cupola that, Logic, we sustain, provides the overall conceptual cupola that,

as a generic module, fluidly articulates together the specific as a generic module, fluidly articulates together the specific modules identified by evolutionary psychology. In that respect, modules identified by evolutionary psychology. In that respect, it is mirrored by the computational universality of computing it is mirrored by the computational universality of computing machines, which can execute any program, compute any machines, which can execute any program, compute any computable function. computable function.

The relation of our argument to logic is ensured by the The relation of our argument to logic is ensured by the philosophical perspective of functionalism: logic itself can be philosophical perspective of functionalism: logic itself can be implemented on top of a symbol processing system, implemented on top of a symbol processing system, independently of the particular physical substrate supporting independently of the particular physical substrate supporting it. it.

There is an obvious human capacity for understanding logical There is an obvious human capacity for understanding logical reasoning, a capacity developed during the course of brain reasoning, a capacity developed during the course of brain evolution. Its most powerful expression today is science itself, evolution. Its most powerful expression today is science itself, and the knowledge amassed from numerous disciplines, each and the knowledge amassed from numerous disciplines, each of which with their own logic nuances dedicated to reasoning of which with their own logic nuances dedicated to reasoning within their domain. From nation state laws to quantum within their domain. From nation state laws to quantum physics, logic, in its general sense, has become the pillar on physics, logic, in its general sense, has become the pillar on which human knowledge is built and improved, the ultimate which human knowledge is built and improved, the ultimate reward for our mastery of language.reward for our mastery of language.

Our Stance on the Unity of SciencesOur Stance on the Unity of Sciences At some point, it seems a materialist pragmatic heuristic to At some point, it seems a materialist pragmatic heuristic to

believebelieve, i.e. to introduce a default postulate, to the effect , i.e. to introduce a default postulate, to the effect

that a unifying consilience of mind and body will be met.that a unifying consilience of mind and body will be met.

Furthermore, we are entitled to pragmatically and Furthermore, we are entitled to pragmatically and

heuristically heuristically presupposepresuppose that the brains we have in that the brains we have in

common, received via ancestral evolution, are indeed common, received via ancestral evolution, are indeed

capable of ever extendable joint agreement regarding the capable of ever extendable joint agreement regarding the

scientific view of our shared reality, especially in view of scientific view of our shared reality, especially in view of

our brains’ plasticity of communication and modelling.our brains’ plasticity of communication and modelling.

Finally, we can pragmatically, and for efficiency’s sake, Finally, we can pragmatically, and for efficiency’s sake,

assumeassume that the very unity of mind-independent reality (a that the very unity of mind-independent reality (a

presumed given) is thereby conducive to the unity of the presumed given) is thereby conducive to the unity of the

sciences themselves.sciences themselves.

Mind Independent RealityMind Independent Reality

We presume a mind-independent reality for at least six We presume a mind-independent reality for at least six

important reasons:important reasons:

To preserve the distinction between true and false with To preserve the distinction between true and false with

respect to factual matters and to operate the idea of truth as respect to factual matters and to operate the idea of truth as

agreement with reality.agreement with reality.

To preserve the distinction between appearance and reality, To preserve the distinction between appearance and reality,

between our between our picturepicture of reality and reality itself. of reality and reality itself.

To serve as a basis for intersubjective communication.To serve as a basis for intersubjective communication.

To furnish the basis for a shared project of communal inquiry.To furnish the basis for a shared project of communal inquiry.

To provide for the fallibilistic view of human knowledge.To provide for the fallibilistic view of human knowledge.

To sustain the causal mode of learning and inquiry and to To sustain the causal mode of learning and inquiry and to

serve as a basis for objectivity of experience.serve as a basis for objectivity of experience.

Epistemic StatusEpistemic Status What is at stake in the present stance is ultimately a What is at stake in the present stance is ultimately a

principle of practice, and thought practice to be sure. principle of practice, and thought practice to be sure.

Accordingly, the justification for our fundamental Accordingly, the justification for our fundamental

presuppositions is not presuppositions is not evidentialevidential at all; postulates as such at all; postulates as such

are not based on evidence. Rather, it is practical and are not based on evidence. Rather, it is practical and

instrumentalistic – pragmatic, in short. It is procedural or instrumentalistic – pragmatic, in short. It is procedural or

functional efficacy that is the crux. functional efficacy that is the crux.

The justification of these postulates lies in their utility: we The justification of these postulates lies in their utility: we

need them to operate our conceptual scheme. need them to operate our conceptual scheme.

Consequently, our unity of science stance’s epistemic Consequently, our unity of science stance’s epistemic

status is not that of an empirical discovery but of an status is not that of an empirical discovery but of an

encompassing presupposition whose ultimate justification encompassing presupposition whose ultimate justification

is a transcendental argument from the very possibility of is a transcendental argument from the very possibility of

communication and inquiry as we typically conduct them.communication and inquiry as we typically conduct them.

Epistemic ToolkitEpistemic Toolkit In some cases, the cognitive tools and instruments of In some cases, the cognitive tools and instruments of

rationality will be found hardware independent. Even then, rationality will be found hardware independent. Even then, the appropriateness of their use in specific real the appropriateness of their use in specific real circumstances and goals will need to be empirically circumstances and goals will need to be empirically determined. There is no universal one-size-fits-all determined. There is no universal one-size-fits-all epistemological recipe, but agreement can be had on the epistemological recipe, but agreement can be had on the relative success of any given tool kit.relative success of any given tool kit.

In any case, partial understanding may also be sought by In any case, partial understanding may also be sought by building intelligent machines, functionalism coming to the building intelligent machines, functionalism coming to the rescue when positing that the material substrate is often not rescue when positing that the material substrate is often not of the essence, that it suffices to realize equivalent of the essence, that it suffices to realize equivalent functionality albeit over different hardware. functionality albeit over different hardware.

Moreover, distinct functioning roads to the same behaviour Moreover, distinct functioning roads to the same behaviour may be had, thereby accruing to our understanding of what may be had, thereby accruing to our understanding of what general intelligence means, toward their symbiotic entwining, general intelligence means, toward their symbiotic entwining, the most recent step in evolutionary epistemology. the most recent step in evolutionary epistemology.

Artificial EpistemologyArtificial Epistemology Epistemology will eventually have the ability to be shared, Epistemology will eventually have the ability to be shared,

be it with robots, aliens or any other entity who must needs be it with robots, aliens or any other entity who must needs

perform cognition to go on existing and program its future. perform cognition to go on existing and program its future.

Creating situated computers and robots means carrying out Creating situated computers and robots means carrying out

our own cognitive evolution by new means. With the virtue our own cognitive evolution by new means. With the virtue

of engendering symbiotic, co-evolving, and self-accelerating of engendering symbiotic, co-evolving, and self-accelerating

loops. Computerized robots reify our scientific theories, loops. Computerized robots reify our scientific theories,

making them objective, repeatable, and part of a commonly making them objective, repeatable, and part of a commonly

constructed extended reality, built upon multi-disciplinary constructed extended reality, built upon multi-disciplinary

unified science.unified science.

Artificial Intelligence and the Cognitive Sciences, by building Artificial Intelligence and the Cognitive Sciences, by building

such entities, provide a huge and stimulating step towards such entities, provide a huge and stimulating step towards

furthering Science Unity, through the very effort of that furthering Science Unity, through the very effort of that

construction. construction.

End of example - references

Philosophy of science - Philosophy of science - exampleexample

David M. Buss, editor (2005), The Handbook of Evolutionary Psychology,

John Wiley & Sons, 2005.

William S. Cooper (2001), The Evolution of Reason: Logic as a Branch of Biology, Cambridge University Press, 2001.

John Holland (1998), Emergence – From Chaos to Order,

Addison-Wesley, 1998.

Steven Mithen (1996), The Prehistory of Mind, Thames and Hudson, 1996.

Stephen Shennan (2002), Genes, Memes and Human History – Darwinian Archaeology and Cultural Evolution, Thames & Hudson, 2002.

Edward O. Wilson (1998), Consilience – The Unity of Knowledge,

Alfred A. Knopf, 1998.

A thinking mapA thinking map We have looked at a large number of We have looked at a large number of

pieces of pieces of reasoningreasoning types, and now we types, and now we need a need a thinkingthinking mapmap of how to best of how to best analyseanalyse, , understandunderstand, and , and evaluateevaluate them. them.

The thinking map, below, is a list of The thinking map, below, is a list of key key questionsquestions you should you should askask when evaluating when evaluating all sorts of arguments – whether all sorts of arguments – whether someone someone else’selse’s or or your ownyour own..

We separate these ‘We separate these ‘Right QuestionsRight Questions’ into ’ into ClarificationClarification, , AnalysisAnalysis and and EvaluationEvaluation, , JudgingJudging CredibilityCredibility, , Causal ExplanationCausal Explanation..

Clarifying ideas - 1Clarifying ideas - 1

The process of reasoning often encounters The process of reasoning often encounters a need for a need for clarificationclarification. Terms may be . Terms may be used, or claims be made, whose meaning used, or claims be made, whose meaning is unclear, vague, imprecise or ambiguous.is unclear, vague, imprecise or ambiguous.

In order to to In order to to evaluateevaluate an an argumentargument skilfully we must first skilfully we must first understandunderstand it. it.

We expound some ‘We expound some ‘right questionsright questions’ which ’ which help clarify what writers and speakers help clarify what writers and speakers mean – including yourself. What is needed mean – including yourself. What is needed depends on the depends on the audienceaudience and on the and on the purposepurpose of the clarification. of the clarification.


1.1. What is the What is the problemproblem? Is it vagueness, ? Is it vagueness, ambiguity, a need for examples or what?ambiguity, a need for examples or what?

2.2. Who is the Who is the audienceaudience? What background ? What background knowledge and beliefs can they be assumed to knowledge and beliefs can they be assumed to have?have?

3.3. Given the audience, what will provide Given the audience, what will provide sufficientsufficient clarificationclarification for the present purposes? for the present purposes?

4.4. Possible Possible sourcessources of clarification: of clarification:a.a. A A dictionary definitiondictionary definition (reporting normal usage). (reporting normal usage).

b.b. A definition/explanation from an A definition/explanation from an authorityauthority in the in the field (reporting specialized usage).field (reporting specialized usage).

c.c. deciding on a meaning; deciding on a meaning; stipulatingstipulating a meaning. a meaning.


5.5. Ways of clarifying terms and ideas:Ways of clarifying terms and ideas:a)a) Giving a Giving a synonymoussynonymous expression or expression or

paraphrase.paraphrase.

b)b) Giving Giving necessarynecessary and and sufficientsufficient conditions (i.e. conditions (i.e. an ‘if and only if’ definition).an ‘if and only if’ definition).

c)c) Giving Giving clear examplesclear examples (and non-examples). (and non-examples).

d)d) Drawing Drawing constrastsconstrasts (what kind of thing and (what kind of thing and what differentiates it from other things).what differentiates it from other things).

e)e) Explaining the Explaining the historyhistory of an expression. of an expression.

6.6. How much detail is needed by this How much detail is needed by this audience in this situation?audience in this situation?

Analysis of argumentsAnalysis of arguments

1.1. What is/are the main What is/are the main Conclusion/sConclusion/s (may be (may be stated or unstated; may be stated or unstated; may be recommendations, explanations, and so on; recommendations, explanations, and so on; conclusion indicator words, like ‘therefore’ conclusion indicator words, like ‘therefore’ may help).may help).

2.2. What are the What are the ReasonsReasons (data, evidence) and (data, evidence) and their their StructureStructure??

3.3. What is the What is the AssumedAssumed (that is, implicit or (that is, implicit or taken from granted, perhaps in the taken from granted, perhaps in the ContextContext)?)?

4.4. Clarify the Clarify the MeaningMeaning (by the terms, claims or (by the terms, claims or arguments) which need it.arguments) which need it.

Evaluation of argumentsEvaluation of arguments5.5. Are the reasons Are the reasons AcceptableAcceptable (including explicit (including explicit

reasons and unstated assumptions – this may reasons and unstated assumptions – this may involve evaluating factual claims, definitions and involve evaluating factual claims, definitions and value judgements and judging the value judgements and judging the CredibilityCredibility of a of a source)?source)?

6.6. Does the reasoning Does the reasoning SupportSupport its conclusion(s) (is the its conclusion(s) (is the support strong, for example ‘beyond reasonable support strong, for example ‘beyond reasonable doubt’, or weak?)doubt’, or weak?)

7.7. Are there Are there Other Relevant Considerations/ArgumentsOther Relevant Considerations/Arguments which strengthen or weaken the case? (You may which strengthen or weaken the case? (You may already know these or may have to construct them.)already know these or may have to construct them.)

8.8. What is your What is your Overall EvaluationOverall Evaluation (in the light of 1 (in the light of 1 through 7)?through 7)?

Judging Credibility - 1Judging Credibility - 1

1.1. Questions about the Questions about the person/sourceperson/source::

a.a. Do they have the relevant Do they have the relevant expertiseexpertise (experience, knowledge, and formal (experience, knowledge, and formal qualifications)?qualifications)?

b.b. Do they have the ability to Do they have the ability to observeobserve accurately accurately (eyesight, hearing, proximity to event, (eyesight, hearing, proximity to event, abseence of distractions, appropriate abseence of distractions, appropriate instruments, skill in using instruments)?instruments, skill in using instruments)?

c.c. Does their Does their reputationreputation suggest they are suggest they are reliable?reliable?

d.d. Does the source have a vested interest or Does the source have a vested interest or biasbias??


2.2. Questions about the Questions about the circumstances/contextcircumstances/context in in which the claim is made?which the claim is made?

3.3. Questions about the Questions about the justificationjustification the source the source offers or can offer in support of the claim:offers or can offer in support of the claim:

a.a. Did the source ‘Did the source ‘witness Xwitness X’ or was ‘’ or was ‘told about Xtold about X’ ?’ ?

b.b. Is it based on ‘Is it based on ‘primaryprimary’ and ‘’ and ‘secondarysecondary’ sources?’ sources?

c.c. Is it based on ‘Is it based on ‘directdirect’ or on ‘’ or on ‘circumstantialcircumstantial’ ’ evidence?evidence?

d.d. Is it based on direct reference to Is it based on direct reference to credibilitycredibility considerations?considerations?


4.4. Questions about the Questions about the nature of the nature of the

claimclaim which influence its credibility: which influence its credibility:

a.a. Is it very Is it very unlikelyunlikely, given other things we , given other things we

know; or is it very know; or is it very plausibleplausible and easy to and easy to

believe?believe?

b.b. Is it a basic Is it a basic observationobservation statement or an statement or an

inferred inferred judgementjudgement??

5.5. Is there Is there corroborationcorroboration from other from other

sources?sources?

Causal explanation - issuesCausal explanation - issues

1.1. What are the What are the causalcausal possibilitiespossibilities in this case? in this case?

2.2. What What evidenceevidence could you find that could you find that wouldwould count count forfor or or againstagainst the likelihood of these the likelihood of these possibilities (if you could find it)?possibilities (if you could find it)?

3.3. What What evidenceevidence do you have already, or can do you have already, or can gather, that is gather, that is relevantrelevant to determining what to determining what causes what? causes what?

4.4. Which possibility is rendered Which possibility is rendered most likelymost likely by by the evidence? (What best explanation the evidence? (What best explanation fits fits bestbest with everything else we know and with everything else we know and believe?) believe?)

Causal explanation – Causal explanation – lessons 1lessons 1

1.1. Many kinds of events are open to explanation Many kinds of events are open to explanation by by rival causesrival causes

2.2. ExpertsExperts can examine the same event can examine the same event evidence and come up with evidence and come up with different causesdifferent causes to explain itto explain it

3.3. Although Although manymany explanations can ‘ explanations can ‘fit the fit the factsfacts’, some seem more ’, some seem more plausibleplausible than others than others

4.4. Most Most communicatorscommunicators will provide you with will provide you with only their only their favouredfavoured causes; the causes; the critical thinkercritical thinker must must generategenerate the the rivalrival causescauses

Causal explanation – Causal explanation – lessons 2lessons 2

5.5. GeneratingGenerating rival causes is a rival causes is a creativecreative

process; usually such causes will process; usually such causes will notnot be be

obviousobvious

6.6. Even scientific Even scientific researchersresearchers frequently frequently failfail to to

acknowledge important acknowledge important rivalrival causescauses for for

their findingstheir findings

7.7. The The certaintycertainty of a particular causal chain is of a particular causal chain is

inverselyinversely relatedrelated toto the number of plausible the number of plausible

rival causesrival causes

Causal explanation – rival Causal explanation – rival causescauses

Can I think of any other way to interpret the Can I think of any other way to interpret the

evidence?evidence?

What else might have caused this act or What else might have caused this act or

these findings?these findings?

If I looked at this from another point of view, If I looked at this from another point of view,

what might I see as important causes?what might I see as important causes?

If this interpretation is incorrect, what other If this interpretation is incorrect, what other

interpretations might make sense?interpretations might make sense?

Causal explanation – strong Causal explanation – strong casecase

The researcher doesn’t have any personal The researcher doesn’t have any personal financial incentive in suggesting the causefinancial incentive in suggesting the cause

The researcher had at least one control group, The researcher had at least one control group, that did not get exposed to the causethat did not get exposed to the cause

Groups that were compared, differed on very few Groups that were compared, differed on very few characteristics other than the causal factor of characteristics other than the causal factor of interestinterest

Participants were randonmly assigned to groupsParticipants were randonmly assigned to groups Participants were unaware of the researchers’ Participants were unaware of the researchers’

hypotheseshypotheses Other researchers have replicated the findingsOther researchers have replicated the findings

Causal explanation – clues 1Causal explanation – clues 1

Is there any evidence that the explanation has Is there any evidence that the explanation has

been critically examined?been critically examined?

Is it likely that social, political, or psychological Is it likely that social, political, or psychological

forces may bias the hypothesis?forces may bias the hypothesis?

What rival causes have not been considered? What rival causes have not been considered?

How credible is the author’s hypothesis How credible is the author’s hypothesis

compared to rival causes?compared to rival causes?

Causal explanation – clues 2Causal explanation – clues 2

Is the hypothesis thorough in accounting Is the hypothesis thorough in accounting

for many puzzling aspects of the events in for many puzzling aspects of the events in

question?question?

How consistent is the hypothesis with all How consistent is the hypothesis with all

the available valuable relevant evidence?the available valuable relevant evidence?

Is the Is the post hocpost hoc fallacy the primary fallacy the primary

reasoning being used to link the events?reasoning being used to link the events?

Statistics - deceptive?Statistics - deceptive?

Authors often provide statistics to Authors often provide statistics to

support their reasoning, and the support their reasoning, and the

statistics appear to be hard evidence.statistics appear to be hard evidence.

However, there are many ways that However, there are many ways that

statistics can be misusedstatistics can be misused

Because problematic statistics are used Because problematic statistics are used

frequently, it is important to identify any frequently, it is important to identify any

problems with themproblems with them

Statistics – assessment Statistics – assessment clues 1clues 1

1.1. Try to find out as much as you can about Try to find out as much as you can about how the statistics were obtained. Ask how the statistics were obtained. Ask “How does the author know?”“How does the author know?”

2.2. Be curious about the type of average Be curious about the type of average being describedbeing described

3.3. Be alert to users of statistics Be alert to users of statistics concluding concluding one thing, but proving anotherone thing, but proving another

4.4. Blind yourself to the author’s statistics and Blind yourself to the author’s statistics and compared the needed statistical evidence compared the needed statistical evidence with the statistics actually providedwith the statistics actually provided

Decision Making – do & Decision Making – do & recommendrecommend

The thinking involved in The thinking involved in decidingdeciding what to what to

dodo, or in , or in recommendingrecommending a course of action, a course of action,

or weighing someone else’s or weighing someone else’s

recommendation, needs special attention recommendation, needs special attention

since it is very common, is often important, since it is very common, is often important,

and has to be evaluated in a distinctive way.and has to be evaluated in a distinctive way.

We are all used to making decisions, but We are all used to making decisions, but

sometimes we do that less sometimes we do that less skilfullyskilfully than we than we

might.might.

Decision Making – personal & Decision Making – personal & policypolicy

We are interested in We are interested in decisionsdecisions about about substantialsubstantial

matters, such as matters, such as personalpersonal ones, like which ones, like which

university to go to, what to study, whether to university to go to, what to study, whether to

take a job, whether to become vegetarian.take a job, whether to become vegetarian.

And also And also policy decisionspolicy decisions, like whether cannabis , like whether cannabis

should be legalized, boxing banned, fox-hunting should be legalized, boxing banned, fox-hunting

with hounds made illegal, or whether parents with hounds made illegal, or whether parents

should be punished when their children break should be punished when their children break

the law, abortion permitted, and so on.the law, abortion permitted, and so on.

Decision Making – react & Decision Making – react & deliberatedeliberate

Sometimes decisions have to be taken Sometimes decisions have to be taken very quickly very quickly – perhaps to deal with an – perhaps to deal with an emergency – and then one just needs to emergency – and then one just needs to act, or act, or reactreact..

But often we have do have time to think, or But often we have do have time to think, or deliberatedeliberate, and, if the decision matters, the , and, if the decision matters, the question is how to make a question is how to make a goodgood decision decision rather than a rather than a poorpoor or a or a worseworse one. one.

Nevertheless, one should not think forever, Nevertheless, one should not think forever, and often a timed-out and often a timed-out combinationcombination of of deliberation and reaction is called for.deliberation and reaction is called for.

Decision Making – evaluate & Decision Making – evaluate & satisficesatisfice

It is common to say that the “It is common to say that the “optimumoptimum” is the ” is the enemy of the “enemy of the “goodgood”. That striving for the ”. That striving for the optimum may end up optimum may end up consumingconsuming all our all our time time and effortand effort, without a decision being reached, without a decision being reached

Striving for the Striving for the sufficiently goodsufficiently good, simply , simply satisficingsatisficing, could have been conducive to an , could have been conducive to an appropriate and timely decision and actionappropriate and timely decision and action

EvaluationEvaluation itself involves an expenditure, in itself involves an expenditure, in time and resources, that must be taken into time and resources, that must be taken into account as part a decision’s account as part a decision’s costcost

Decision Making – common Decision Making – common flaws 1flaws 1

Did not give the matter enough Did not give the matter enough

thoughtthought

Did the first thing we thought ofDid the first thing we thought of

Didn’t think of possible alternativesDidn’t think of possible alternatives

Didn’t consider the consequences of Didn’t consider the consequences of

various courses of actionvarious courses of action

Decision Making – common Decision Making – common flaws 2flaws 2

Needed to get some more informationNeeded to get some more information

Was too hastyWas too hasty

Was too emotionally involvedWas too emotionally involved

Did what the ‘boss’ saidDid what the ‘boss’ said

Accepted without thinking what others Accepted without thinking what others

suggestedsuggested

Decision Making – thinking Decision Making – thinking map 1map 1

1.1. What makes this decision What makes this decision NecessaryNecessary? ? [Objectives?][Objectives?]

2.2. What is What is RecommendedRecommended and on what and on what GroundsGrounds??

3.3. What are the What are the Options/AlternativesOptions/Alternatives? ? Realistic or unusual?Realistic or unusual?

4.4. What are the What are the Possible ConsequencesPossible Consequences of of the various options the various options – and – and How LikelyHow Likely are are they? (On the basis of what evidence and they? (On the basis of what evidence and how reliable is it?)how reliable is it?)

Decision Making – thinking Decision Making – thinking map 2map 2

5.5. How How ImportantImportant are these consequences – are these consequences – for all those affected?for all those affected?

6.6. When I When I CompareCompare the alternatives in the the alternatives in the light of the consequences, which is best? Is light of the consequences, which is best? Is the recommended course best?the recommended course best?

7.7. How can I carry out this decision? How can I carry out this decision? ((ContingencyContingency plans?) plans?)

8.8. Is the decision taking too long and what is Is the decision taking too long and what is the cost of that? Is there a the cost of that? Is there a satisficingsatisficing solution?solution?

Decision Making – summary Decision Making – summary 11

The thinking involved in making The thinking involved in making decisionsdecisions or or

in recommending a course of action in recommending a course of action

deserves special deserves special attentionattention..

We often do this poorly because we We often do this poorly because we jump to jump to

a decisiona decision and afterwards and afterwards rationaliserationalise it. it.

To make decisions well and To make decisions well and avoidavoid the the

common common weaknessesweaknesses, we need to , we need to considerconsider a a

reasonable range of reasonable range of optionsoptions and their and their

possible possible consequences beforeconsequences before coming to a coming to a

decision or an advice. decision or an advice.

Decision Making – summary Decision Making – summary 22

Getting Getting clearclear what the problem is may what the problem is may

necessitate formulating necessitate formulating objectivesobjectives..

In thinking of In thinking of consequencesconsequences we need to be we need to be

as as imaginativeimaginative as possible, but also to as possible, but also to judgejudge

carefully carefully how likelyhow likely they are, and they are, and how how

valuablevaluable, to come to a rational decision., to come to a rational decision.

To do this we may also need to undertake To do this we may also need to undertake

some some investigationsinvestigations and take account of and take account of

moralmoral considerations. considerations.

Omitted information - 1Omitted information - 1 By asking questions brought up in other By asking questions brought up in other

sections, such as concerning ambiguity, sections, such as concerning ambiguity, assumptions, and evidence, we will detect assumptions, and evidence, we will detect much important much important missing informationmissing information

A more A more complete searchcomplete search for omitted for omitted information, however, is so important to information, however, is so important to critical evaluation that it deserves additional critical evaluation that it deserves additional emphasisemphasis

Next we further sensitise to the importance of Next we further sensitise to the importance of what is not said what is not said and remind that we react to and remind that we react to an incomplete picture of an argument when an incomplete picture of an argument when we evaluate only the we evaluate only the explicitexplicit parts parts

Omitted information - 2Omitted information - 2

Almost any Almost any informationinformation we encounter has a we encounter has a purposepurpose. Its organization was selected and . Its organization was selected and established by someone who hoped that it established by someone who hoped that it would affect our thinking in some designed would affect our thinking in some designed wayway

Those trying to Those trying to persuadepersuade us will almost us will almost always try to present their position in the always try to present their position in the strongeststrongest possible possible lightlight

It is It is wise towise to hesitatehesitate and think about what and think about what an author may an author may notnot have toldhave told us, something us, something our critical questioning has not yet revealedour critical questioning has not yet revealed

Omitted information - 3Omitted information - 3

Omitted information is inevitable, for at Omitted information is inevitable, for at least five reasons:least five reasons:

1.1. Time and space limitationsTime and space limitations

2.2. Limited attention spanLimited attention span

3.3. Inadequacies inhuman knowledgeInadequacies inhuman knowledge

4.4. DeceptionDeception

5.5. Existence of different perspectivesExistence of different perspectives

Clues for finding omitted Clues for finding omitted informationinformation

1.1. Common counterargumentsCommon counterarguments

a.a. What reasons would someone who What reasons would someone who disagrees offer?disagrees offer?

b.b. Are there research studies that Are there research studies that contradict the studies presented?contradict the studies presented?

c.c. Are there missing examples, Are there missing examples, testimonials, or analogies that support testimonials, or analogies that support the other side of the argument?the other side of the argument?

2.2. Missing definitions:Missing definitions: How would the How would the arguments differ if key terms were arguments differ if key terms were defined in other ways?defined in other ways?


3.3. Missing value preferences or perspectivesMissing value preferences or perspectives

a.a. From what other set of values might one From what other set of values might one approach this issue?approach this issue?

b.b. What kinds of arguments would be made by What kinds of arguments would be made by someone approaching the issue from a someone approaching the issue from a different set of values?different set of values?

4.4. Origins of “facts” alluded to in the argumentOrigins of “facts” alluded to in the argument

a.a. Where do the arguments come from?Where do the arguments come from?

b.b. Are the factual claims supported by Are the factual claims supported by competent research or by reliable sources?competent research or by reliable sources?


5.5. Details of procedures used for gathering factsDetails of procedures used for gathering facts

a.a. How many people completed the How many people completed the

questionnaire?questionnaire?

b.b. How were the survey questions worded?How were the survey questions worded?

6.6. Alternative techniques for gathering or Alternative techniques for gathering or

organizing evidence:organizing evidence:

How might the results from an interview How might the results from an interview study study

differ from questionnaire results?differ from questionnaire results?

DecisionDecision

SummarySummary

Descriptive, normative, prescriptiveDescriptive, normative, prescriptive

Expected Utility: normative theory of decisionExpected Utility: normative theory of decision

Psychology of decisionPsychology of decision

Prospect theory: descriptive theory of decisionProspect theory: descriptive theory of decision

Thinking map: prescription for decidingThinking map: prescription for deciding

Clues for finding omitted information Clues for finding omitted information

(continuation)(continuation)

TheoriesTheories

DescriptiveDescriptive

What isWhat is

NormativeNormative

What is betterWhat is better

PrescriptivePrescriptive

What to doWhat to do

TheoriesTheories

Example: Shopping for groceriesExample: Shopping for groceries

Descriptive: prices, products, Descriptive: prices, products,

supermarkets…supermarkets…

Normative: a better deal is less $$, more, Normative: a better deal is less $$, more,

quality…quality…

Prescriptive: 1º LIDL; 2º Feira Nova for the Prescriptive: 1º LIDL; 2º Feira Nova for the

restrest

Expected UtilityExpected Utility

Normative theory of decisionNormative theory of decision

Utility in a broad sense (“goodness”)Utility in a broad sense (“goodness”)

Premises of Expected UtilityPremises of Expected Utility

Values are relativeValues are relative

-How is your wife?-How is your wife?

-Compared to what?-Compared to what?


Weak (partial) ordering.Weak (partial) ordering.

Either prefers A to B, prefers B to A, or indifferentEither prefers A to B, prefers B to A, or indifferent

Transitive: if prefers A to B and B to C, prefers A Transitive: if prefers A to B and B to C, prefers A

to Cto C



Sure thing principleSure thing principle

1%1% 99%99%

Game XGame X CarCar CrackersCrackers

Game YGame Y Luxury CruiseLuxury Cruise CrackersCrackers

Ignore crackers when picking gameIgnore crackers when picking game



Sure thingSure thing

Implies that:Implies that:

E.U. = E.U. = p pii x u x uii

Expected utility is the sum of the utilities of Expected utility is the sum of the utilities of

outcomes multiplied by their probabilitiesoutcomes multiplied by their probabilities


Example:Example:

Lottery :50,000€ with 1/100,000 probability.Lottery :50,000€ with 1/100,000 probability.

Expected utility = Expected utility =

50,000/100,000 + 1*(-20)= -19.5€50,000/100,000 + 1*(-20)= -19.5€

(is utility equal to monetary value?...)(is utility equal to monetary value?...)

Psychology of DecisionPsychology of Decision

Thinking: one-sided versus two-sidedThinking: one-sided versus two-sided

Favouring one-sided thinking:Favouring one-sided thinking:

Hesitation or changing one’s mind is badHesitation or changing one’s mind is bad

Mimicking expertsMimicking experts

Confusing decision with advocacyConfusing decision with advocacy


Thinking: Self deceptionThinking: Self deception

TestTest: cold pressor pain test: cold pressor pain test

With Good/bad heart, exercise increased With Good/bad heart, exercise increased

tolerancetolerance

Exercise, repeat testExercise, repeat test

Resistance changed depending on what Resistance changed depending on what

subjects were told…subjects were told…


Thinking: Self deceptionThinking: Self deception

Most drivers believe they are better than Most drivers believe they are better than

average.average.

Most people believe to have better than Most people believe to have better than

average chances of reaching 80.average chances of reaching 80.


Thinking: Belief overkillThinking: Belief overkill

People opposed to nuclear tests believe People opposed to nuclear tests believe

them to be a medical danger, source of them to be a medical danger, source of

instability, and not lead to instability, and not lead to

improvements.improvements.

People in favour believed the opposite.People in favour believed the opposite.


Thinking: Belief overkillThinking: Belief overkill

People opposed to death penalty believe not People opposed to death penalty believe not

to be deterrent and morally wrong.to be deterrent and morally wrong.

People in favour believed it to be a deterrent People in favour believed it to be a deterrent

and morally acceptable.and morally acceptable.


Bernoulli, St. Petersburg Paradox:Bernoulli, St. Petersburg Paradox:

Flip coin until it lands “heads”. Pays 1€ if on Flip coin until it lands “heads”. Pays 1€ if on

first throw, 2€ on second, 4€ on third…first throw, 2€ on second, 4€ on third…

Expected:Expected:

½ * 1+ ¼ * 2 + 1/8 * 4 +… =½ * 1+ ¼ * 2 + 1/8 * 4 +… =

½ + ½ + ½ + … = ½ + ½ + ½ + … =



With infinite expected return anyone should With infinite expected return anyone should

pay to play this game. Why don’t they? pay to play this game. Why don’t they?



Utility is a log function of value?Utility is a log function of value?Utility

Value


Framing:Framing:

Game 1: Game 1:

25% chance of winning level.25% chance of winning level.

Must choose prize:Must choose prize:

A: 100% 30€A: 100% 30€ B: 80% 45€B: 80% 45€

Game 2: Game 2:

A: 25% 30€A: 25% 30€ B: 20% 45€B: 20% 45€


Allais Paradox (sure thing)Allais Paradox (sure thing)

Situation X:Situation X:

1: 100% 1k€1: 100% 1k€ 2:89% 1k€ 10% 5k€ 2:89% 1k€ 10% 5k€

1% 0€1% 0€

Situation Y:Situation Y:

3: 11% 1k€ 89% 0€3: 11% 1k€ 89% 0€ 4:10% 5k€ 90% 4:10% 5k€ 90%

0€0€


Allais Paradox (sure thing)Allais Paradox (sure thing)


1: 100% 1k€1: 100% 1k€ 2:89% 1k€ 10% 5k€ 2:89% 1k€ 10% 5k€

1% 0€1% 0€


3: 11% 1k€ 89% 0€3: 11% 1k€ 89% 0€ 4:10% 5k€ 90% 4:10% 5k€ 90%

0€0€


Allais Paradox (sure thing) Equivalent to:Allais Paradox (sure thing) Equivalent to:

11 2-112-11 12-10012-100


1:1: 1k€1k€ 1k€1k€ 1k€1k€

2:2: 0€0€ 5k€5k€ 1k€1k€


3:3: 1k€1k€ 1k€1k€ 0€0€

4:4: 0€0€ 5k€5k€ 0€0€

Prospect TheoryProspect Theory

Kahneman, Tversky, 1979Kahneman, Tversky, 1979

Probability: Probability: , not p, not p


Probability: Probability: , not p, not p

Allais paradoxAllais paradox

Game 30€ or 45€Game 30€ or 45€


Utility not linear:Utility not linear:


Framing effects:Framing effects:

Gas 0.95€Gas 0.95€

Card Surcharge 0.05€Card Surcharge 0.05€

Gas 1.00€Gas 1.00€

Cash discount 0.05€Cash discount 0.05€



Outbreak expected toOutbreak expected to

Kill 600.Kill 600.

A: Save 200A: Save 200

B: Save 600, p=33%B: Save 600, p=33%



Outbreak expected toOutbreak expected to

Kill 600.Kill 600.

A: 400 dieA: 400 die

B: 600 die, p=67%B: 600 die, p=67%

Prescriptive: Thinking MapPrescriptive: Thinking Map

1.1. Necessity. Objectives.Necessity. Objectives.

2.2. Recommendations?Recommendations?

3.3. Options/Alternatives.Options/Alternatives.

4.4. Consequences: LikelihoodConsequences: Likelihood and and Importance. Importance.

5.5. Compare the alternatives. Compare the alternatives.

6.6. Feasibility and contingency plans. Feasibility and contingency plans.

7.7. Check the cost of deciding.Check the cost of deciding.


1.1. Necessity. Objectives.Necessity. Objectives.

2.2. Recommendations?Recommendations?Keep in mind the objectives.Keep in mind the objectives.

Look for previous solutions or Look for previous solutions or recommended actions.recommended actions.


3.3. Options/Alternatives.Options/Alternatives.

4.4. Consequences: LikelihoodConsequences: Likelihood and and Importance Importance

Decision is a search process.Decision is a search process.

Consider different alternatives.Consider different alternatives.

Check if you have enough information to Check if you have enough information to estimate consequences and estimate consequences and likely likely outcomes.outcomes.

Avoid single-mindedness…Avoid single-mindedness…


[continued from before][continued from before]7.7. Missing or incomplete figures, graphs, Missing or incomplete figures, graphs,

tables or datatables or data

a.a. Would the figure look different if it Would the figure look different if it

included evidence from earlier or later included evidence from earlier or later

years?years?

b.b. Has the author “stretched” the figure Has the author “stretched” the figure

to make the difference look larger?to make the difference look larger?


8.8. Omitted effects, both positive and Omitted effects, both positive and negative, and both short- and long-term, negative, and both short- and long-term, of what is advocated or what is opposedof what is advocated or what is opposed

a.a. Has the argument left out important Has the argument left out important positive or negative consequences of a positive or negative consequences of a proposed action?proposed action?

b.b. Do we need to know the impact of the Do we need to know the impact of the action on any of the following areas: action on any of the following areas: political, social, economic, biological, political, social, economic, biological, spiritual, health, or environmental?spiritual, health, or environmental?


9.9. Context of quotes and testimonialsContext of quotes and testimonialsHas a quote or testimonial been taken Has a quote or testimonial been taken

out of out of context?context?

10.10. Benefits accruing to the author from Benefits accruing to the author from convincing others to follow his advice?convincing others to follow his advice?

Will the author benefit Will the author benefit financially if we adopt financially if we adopt his proposed his proposed policy?policy?

11.11. Has the author left out any other information Has the author left out any other information I need to know before I make my judgement?I need to know before I make my judgement?

Importance of the negative Importance of the negative viewview

There is one type of omitted information that There is one type of omitted information that is so important to identify: the potential is so important to identify: the potential negative effectsnegative effects of actions being advocated of actions being advocated

We need to ask:We need to ask:

– Which segmentsWhich segments of society doof society do not not benefit benefit from a proposed action? Who loses? What from a proposed action? Who loses? What do the losers have to say about it?do the losers have to say about it?

– How does the proposed action affect the How does the proposed action affect the distribution of power?distribution of power?


– DoesDoes the action influence the extent of the action influence the extent of

democracy in our society?democracy in our society?

– How does a particular action affect how we How does a particular action affect how we

view the world: what we think, how we view the world: what we think, how we

think, and what we know and can know?think, and what we know and can know?

– What the are the action’s effects on our What the are the action’s effects on our

health?health?


– How does the action influence our relationships How does the action influence our relationships

with one another? With the natural with one another? With the natural

environment?environment?

– Will the action have a slow, cumulative impact?Will the action have a slow, cumulative impact?

– What are the potential long-term negative What are the potential long-term negative

effects of the action?effects of the action?


Opportunity costs.Opportunity costs.

What do we loose by not gaining something What do we loose by not gaining something else?else?

E.g.E.g.

Investment 1Investment 1: returns €11,500: returns €11,500

Investment 2Investment 2: returns €11,000 but we must : returns €11,000 but we must use use material worth €1,000material worth €1,000


5.5. Compare the alternatives. Compare the alternatives. Expected utility.Expected utility.

Weigh multiple attributes.Weigh multiple attributes.

6.6. Feasibility and contingency plans. Feasibility and contingency plans.

7.7. Check the cost of deciding.Check the cost of deciding. Decision and implementation must be Decision and implementation must be

feasible.feasible.

Multiple conclusions - 1Multiple conclusions - 1

Rarely will we have a situation where in Rarely will we have a situation where in which only one alternative conclusion can be which only one alternative conclusion can be reasonably inferredreasonably inferred

We have to make sure that the conclusion We have to make sure that the conclusion we eventually adopt is the most reasonable we eventually adopt is the most reasonable and the most consistent with our value and the most consistent with our value preferencespreferences

The recognition that the reasons could The recognition that the reasons could provide support for alternative conclusions provide support for alternative conclusions should heighten our interest in any further should heighten our interest in any further tests or studies that would help identify the tests or studies that would help identify the best conclusionbest conclusion

Multiple conclusions - 2Multiple conclusions - 2 If we make different assumptions concerning If we make different assumptions concerning

the meaning of the reasons, we will reach the meaning of the reasons, we will reach different conclusionsdifferent conclusions

Even when an author mentions alternative Even when an author mentions alternative conclusions, we can often generate other conclusions, we can often generate other alternatives by imagining different assumptionsalternatives by imagining different assumptions

Few important questions can be answered with Few important questions can be answered with a simple “yes” or “no”. Dichotomous of a simple “yes” or “no”. Dichotomous of thinking assumes there are only two possible thinking assumes there are only two possible answers to a question even when it has answers to a question even when it has possible multiple answers. It often fails to take possible multiple answers. It often fails to take in contextin context


If can create multiple conclusions by judicious If can create multiple conclusions by judicious

use of “use of “if-clausesif-clauses”. In an if-clause, we state a ”. In an if-clause, we state a

condition that we are assuming in order to condition that we are assuming in order to

enable us to to reach a particular conclusionenable us to to reach a particular conclusion

The use of if-clauses permits us to arrive at a The use of if-clauses permits us to arrive at a

conclusion without pretending to know more conclusion without pretending to know more

than we do. Use of if-clauses preceding a than we do. Use of if-clauses preceding a

conclusion points out the it is based on conclusion points out the it is based on

particular claims or assumptions about which particular claims or assumptions about which

we are uncertainwe are uncertain


Frequently we encounter issues posed in Frequently we encounter issues posed in the form:the form:

Should we do X?Should we do X? Is X desirable?Is X desirable? Such questions pull for dichotomous Such questions pull for dichotomous

reasoning. Often such questions hide a reasoning. Often such questions hide a broader question:broader question:

What should we do about Y?What should we do about Y? Rewording the question leads us to Rewording the question leads us to

generate multiple conclusions, and generate multiple conclusions, and increases the flexibility in our thinkingincreases the flexibility in our thinking

Strategies for effective CTStrategies for effective CT

1.1. Be certain to demonstrate that you really Be certain to demonstrate that you really

want to grasp what is being said. Ask want to grasp what is being said. Ask

questions that indicate your willingness to questions that indicate your willingness to

grasp and accept new conclusionsgrasp and accept new conclusions

2.2. Resate what you heard or read and ask Resate what you heard or read and ask

whether your understanding of the whether your understanding of the

argument is consistent with what was argument is consistent with what was

spoken or writtenspoken or written


3.3. Voice your critical questions as if you are Voice your critical questions as if you are

curious. Nothing is more deadly to curious. Nothing is more deadly to

effective use of CT than an attitude of effective use of CT than an attitude of

“aha, I caught you making an error.”“aha, I caught you making an error.”

4.4. Request additional reasons that might Request additional reasons that might

enable the person to make a stronger enable the person to make a stronger

argument than the one originally argument than the one originally

providedprovided


5.5. Work hard to keep the conversation going. If Work hard to keep the conversation going. If CT is deployed like a weapon, thinking on that CT is deployed like a weapon, thinking on that topic is haltedtopic is halted

6.6. Ask for permission to explore any weaknesses Ask for permission to explore any weaknesses

in the reasoning, so that the other person will in the reasoning, so that the other person will

examine the argument with youexamine the argument with you

7.7. Convey the impression that you and the other Convey the impression that you and the other

person are collaborators, working toward the person are collaborators, working toward the

same objective same objective – improved conclusions– improved conclusions

Open-minded thinking - 1Open-minded thinking - 1

In the critical thinking search framework, In the critical thinking search framework, things can go wrong for three reasons:things can go wrong for three reasons:

1.1. Our search for misses something that it Our search for misses something that it should have discovered, or we act with should have discovered, or we act with high confidence after little search.high confidence after little search.

2.2. We seek evidence and make inferences in We seek evidence and make inferences in ways that prevent us from choosing the ways that prevent us from choosing the best possibility.best possibility.

3.3. We think too much, without arriving at a We think too much, without arriving at a worthwhile conclusion or decision.worthwhile conclusion or decision.

Open-minded thinking - 2Open-minded thinking - 2 The 2nd problem seems to be the most serious. The 2nd problem seems to be the most serious.

People tend to seek evidence, seek goals, and People tend to seek evidence, seek goals, and make inferences in a way that favours make inferences in a way that favours possibilities that already appeal to them. E.g., we possibilities that already appeal to them. E.g., we often ignore evidence that goes against often ignore evidence that goes against possibilities that we like.possibilities that we like.

The favouritism for a particular possibility may The favouritism for a particular possibility may cause us to prematurely cut off our search for cause us to prematurely cut off our search for alternative possibilities, or for reasons against alternative possibilities, or for reasons against the one we have in mind. This favouritism leads the one we have in mind. This favouritism leads to insufficient thinking or to overconfidence in to insufficient thinking or to overconfidence in hasty conclusions – the 1st reason above.hasty conclusions – the 1st reason above.

Open-minded thinking - 3Open-minded thinking - 3 Poor thinking tends to be characterized by Poor thinking tends to be characterized by

too little search, by overconfidence in hasty too little search, by overconfidence in hasty conclusions, and by biases in favour of the conclusions, and by biases in favour of the possibilities that were prefered initially.possibilities that were prefered initially.

Good thinking consists of Good thinking consists of (1)(1) search that is search that is thorough in proportion to the importance of thorough in proportion to the importance of the question, the question, (2)(2) confidence that is confidence that is appropriate to the amount of and quality of appropriate to the amount of and quality of thinking done, and thinking done, and (3)(3) fairness to other fairness to other possibilities than the one we initially favour.possibilities than the one we initially favour.

Open-minded thinking - 4Open-minded thinking - 4 An important part of active open-minded thinking An important part of active open-minded thinking

is fairness to possibilities regardless of their initial is fairness to possibilities regardless of their initial strength. People tend to possibilities that are strength. People tend to possibilities that are already strong, when searching and inferring, already strong, when searching and inferring, known as “myside bias”.known as “myside bias”.

Irrational belief persistence may result from Irrational belief persistence may result from myside bias, in that incorrect beliefs are slow to myside bias, in that incorrect beliefs are slow to change, and may become even stronger instead change, and may become even stronger instead of weaker.of weaker.

Some amount of belief persistence is not Some amount of belief persistence is not irrational. Older beliefs tend to have passed more irrational. Older beliefs tend to have passed more tests than new ones.tests than new ones.

Open-minded thinking - 5Open-minded thinking - 5 When the order in which we encounter two pieces When the order in which we encounter two pieces

of evidence is not itself informative, the order of evidence is not itself informative, the order should have no effect on final strength of belief.should have no effect on final strength of belief.

““Neutral evidence” should not strengthen belief, Neutral evidence” should not strengthen belief, meaning evidence that, on the whole, is equally meaning evidence that, on the whole, is equally consistent with a belief and its converse.consistent with a belief and its converse.

Many controversial issues are so since there are Many controversial issues are so since there are good arguments on both sides. A rational decision good arguments on both sides. A rational decision involves balancing the arguments quantitatively, involves balancing the arguments quantitatively, taking into account their relative strengths. But taking into account their relative strengths. But people find ways of avoiding this balancing.people find ways of avoiding this balancing.

Ethics - 1Ethics - 1 Moral thinking is important for decision Moral thinking is important for decision

making as a whole, since most real making as a whole, since most real decisions involve moral issues.decisions involve moral issues.

We often are not aware that moral issues We often are not aware that moral issues are involved in our everyday decisions, are involved in our everyday decisions, but whenever our choices affect the but whenever our choices affect the “utilities” of others, a moral decision must “utilities” of others, a moral decision must be made.be made.

The most basic moral judgements are The most basic moral judgements are statements about what decision someone, statements about what decision someone, in a certain situation or kind of situation, in a certain situation or kind of situation, should make.should make.

Ethics - 2Ethics - 2 The traditional beliefs we are taught may The traditional beliefs we are taught may

represent the the conclusions of good moral represent the the conclusions of good moral

thinking done by others in the past, but when thinking done by others in the past, but when

they are passed on to us in the form of beliefs they are passed on to us in the form of beliefs

that we cannot question, we do not learn the that we cannot question, we do not learn the

details of the normative theories that stand details of the normative theories that stand

behind them, if any.behind them, if any.

The philosophy that underlies utility theory The philosophy that underlies utility theory – –

utilitarianism utilitarianism – is one such normative theory.– is one such normative theory.

Does being moral conflict with maximizing Does being moral conflict with maximizing

expected overall utility? Some do.expected overall utility? Some do.

Ethics - 3Ethics - 3 We can begin to understand morality by asking We can begin to understand morality by asking

about the functions it serves.about the functions it serves.

Morality can be expressed in how we try to Morality can be expressed in how we try to

influence others: teaching principles directly by influence others: teaching principles directly by

explaining them or by deploying moral explaining them or by deploying moral

emotions; setting examples of how to behave; emotions; setting examples of how to behave;

gossiping; rewarding behaviour that follows the gossiping; rewarding behaviour that follows the

principles and punishing that which violates principles and punishing that which violates

them; supporting, justifying, opposing, or them; supporting, justifying, opposing, or

violating, institutional laws or rulesviolating, institutional laws or rules

Ethics - 4Ethics - 4

The naturalistic fallacy is to draw a The naturalistic fallacy is to draw a conclusion about what conclusion about what oughtought to be true to be true solely from what solely from what isis true. It reflects one kind true. It reflects one kind of confusion about the origin of moral rules.of confusion about the origin of moral rules.

A moral rule or judgement is a type of A moral rule or judgement is a type of premise to which anyone can appeal. It goes premise to which anyone can appeal. It goes beyond specific cases. Failure to understand beyond specific cases. Failure to understand that moral rules are impersonal results in the that moral rules are impersonal results in the fallacy of realtivism, where moral questions fallacy of realtivism, where moral questions are simply a matter of taste.are simply a matter of taste.

Ethics - 5Ethics - 5 One approach is to regard moral thinking as an One approach is to regard moral thinking as an

extension of decision making. Some of the errors extension of decision making. Some of the errors people make in moral thinking are alike those people make in moral thinking are alike those they commit in decision making. They include: they commit in decision making. They include: failure to recognize the precedent-setting effects failure to recognize the precedent-setting effects of choices; neglect of the consequences of a of choices; neglect of the consequences of a choice for the feelings of others; neglect of the choice for the feelings of others; neglect of the consequences for those far away or in the consequences for those far away or in the future; failure to recognize the conflict between future; failure to recognize the conflict between self-interest and that of others; and the self-interest and that of others; and the omission-commission framing effect.omission-commission framing effect.

Discussion of such errors does not imply Discussion of such errors does not imply acceptance or rejection of any given moral code.acceptance or rejection of any given moral code.

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Cri Թ tical Thinking Luís Moniz Pereira Departamento de Informática FCT/UNL 1st sem. 06/07 Critical Thinking – jump to 14 for slides in English