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The 4th International Conference on Cognitive Neurodynamics ICCN2013VERY ROUGH DRAFT (2013-10-24) , PLEASE DO NOT CIRCULATE
Weak vs. strong quantum cognition
Paavo Pylkknen
Department of Cognitive Neuroscience and Philosophy, University of Skvde,
P.O. Box 408, SE-541 28 Skvde, Sweden andDepartment of Philosophy, History, Culture and Art Studies, P.O. Box 24, FI-
00014 University of Helsinki, Finland.
e-mail:[email protected]
Abstract In recent decades some cognitive scientists have adopted a program ofquantum cognition. For example, Pothos and Busemeyer (PB) argue that there are
empirical results concerning human decision-making and judgment that can beelegantly accounted for by quantum probability (QP) theory, while classical
(Bayesian) probability (CP) theory fails. They suggest that the reason why
quantum probability works better is because some cognitive phenomena are
analogous to quantum phenomena. This naturally gives rise to a further question
about why they are analogous. Is this a pure coincidence, or is there a deeper
reason? For example, could the neural processes underlying cognition involvesubtle quantum effects, thus explainingwhy cognition obeys QP? PB are agnostic
about this controversial issue, and thus their kind of program could be labeled asweak quantum cognition (analogously to the program of weak artificial
intelligence as characterized by Searle). However, there is a long tradition of
speculating about the role of subtle quantum effects in the neural correlates ofcognition, constituting a program of strong quantum cognition or quantumcognitive neuroscience. In this paper I will be considering the prospects of
strong quantum cognition, by briefly reviewing and commenting on some of thekey proposals.
Keywords
Quantum cognition, quantum probability, analogy
1. Introduction
In their recent Behavioral and Brain Science target article Can quantumprobability provide a new direction for cognitive modeling? Emmanuel Pothos
and Jerome Busemeyer (PB) (2013) make a convincing case that there are
empirical results concerning human decision making and judgment that can be
elegantly accounted for by quantum probability (QP) theory, while classical
(Bayesian) probability (CP) theory fails. In particular, they point out that human
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judgment and preference often display order and context effects, violations of the
law of total probability and failures of compositionality, and that in such cases QP
- with features such as superposition and entanglement - provides a natural
explanation of cognitive process. More generally, they suggest that QP is
potentially relevant in any behavioral situation that involves uncertainty.
Such success in modeling raises the question of how can it be that QP
which was developed to account for quantum physical phenomena could possibly
be able to account for cognitive phenomena. PB do not discuss this issue at great
length, but suggest that the reason is because some cognitive phenomena are
analogous to quantum phenomena. But this gives rise to a further question: why
are these phenomena analogous to each other? Is it a mere coincidence or is there
some deeper explanation? For example, might the neural processes underlying
cognition be quantum-like in some way? PB remain agnostic about thiscontroversial issue, and thus we might call their program an instance of weak
quantum cognition (somewhat analogously to the program of weak AI in
artificial intelligence research; cf. also the program of weak quantum theory,
where one applies some, but not all formal features of quantum theory to explain
cognitive phenomena, see Atmaspacher et al. 2002). However, there is a long
tradition of speculating about the role of subtle quantum effects in the neural
correlates of cognition, constituting a program of strong quantum cognition or
quantum cognitive neuroscience. While it may be a good research strategy in
cognitive science to pursue weak quantum cognition without worrying about the
underlying reasons for why QP works for cognition, it would clearly be a major
scientific breakthrough is strong quantum cognition would turn out to be correct.
It is thus worth giving attention to the current state-of-the-art in strong quantumcognition. The aim of this paper is to briefly review and comment some major
developments.
2. Strong quantum cognition: subtle quantum effects in the neural correlates
of cognition?
There are various ways in which the neural processes underlying cognition could
be quantum-like. The strongest possibility is that they literally involve subtle
quantum effects. For example, following Niels Bohr, David Bohm speculated
about this possibility already in 1951 in his textbookQuantum theory.
Anticipating the current research on quantum cognition, he drew attention to what
he considered to be remarkable point-by-point analogies between quantum
processes and thought. He added that it would provide a natural explanation of
these analogies if it turned out that some key neural processes (e.g. in synapses)
were subject to quantum-theoretical limitations (for a discussion of Bohms
analogies see
Pylkknen 2004).
Harald Atmanspacher (2011) has provided a useful overview of various
programs of what I have above call strong quantum cognition. First of all, there
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are approaches that stay within the usual interpretation of the quantum theory.
There is the von Neumann-Wigner line of thought that assumes that consciousness
plays a role in quantum state reductions; in Stapps later development of this
approach the neural correlates of conscious intentional acts are assumed to involve
quantum state reductions. There is the Ricciardi-Umezawa-Vitiello approach that
sees mental states, particularly memory states, as vacuum states of quantum fields
(this approach has been given an imaginative philosophical interpretation by
Globus 2003). Finally, there is the Beck-Eccles approach, where it is assumed
that due to quantum mechanical processes the frequency of exocytosis at a
synaptic cleft can be controlled by mental intentions, without violating the
conservation of energy (for a discussion of this last approach see also Hiley and
Pylkknen 2005).
Atmanspacher also draws attention to programs of strong quantumcognition that involve further extensions or generalizations of present-day
quantum theory. Most notably, there is Penroses proposal that human (say
mathematical) insight is non-computable and that the physiological correlates of
such insight thus need to involve non-computable physical processes. He thinks
that such process might well be related to quantum state reduction. However,
Penrose is not satisfied with quantum state reduction as this is characterized in the
usual interpretation of quantum theory. Instead, he proposes that gravity brings
about the reduction under certain circumstances, which allows the possibility of an
orchestrated objective reduction (ORCH-OR) the idea being that the reduction
can take place without the activity of a human conscious observer, and in an
orchestrated way. This involves an extension of current quantum theory, in which
latter the state reductions obey the usual laws of quantum probability. Togetherwith Hameroff, Penrose proposed that neural microtubules might provide a site
where ORCH-ORs could take place. Their assumption is that ORCH-ORs in
neural microtubules constitute conscious moments. The idea is similar to Stapps
later ideas, but one difference is that while Stapp stays within the usual
interpretation of quantum theory, Penroses approach involves going beyond it (in
that the reductions can be objective and orchestrated, and need not obey the usual
quantum laws).
Those who advocate strong quantum cognition typically encounter the
criticism that quantum effects are washed out in the warm, wet and noisy
conditions of the macroscopic world and brains in particular (the decoherence
problem). It is thus concluded that quantum theory is only relevant to physical
processes in the (sub)atomic domain and should be ignored in other physical
domains. However, there are many recent research developments suggesting that
biological organisms at ordinary temperatures exploit subtle quantum effects, and
biological evolution would thus have been able to solve the decoherence problem
at least in some biological contexts (e.g. the studies on energy-harvesting in
photosynthesis and avian magnetoreception; for a short review, see Ball, P.
(2011)). As Atmanspacher points out, it is however still a controversial issue
whether subtle quantum processes play a significant role in the neural correlates of
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cognition and consciousness.
Note that those researchers who accept that cognition is quantum-like and
seek to explain this in neural terms need not necessarily adopt the program of
strong quantum cognition. For there is also the possibility that the neural processes
underlying cognition involve no subtle quantum effects, but can nevertheless give
rise to quantum-like neural activity. Something like this is implied by Barros and
Suppes (2009) when they suggest that classicalinterference in the brain may lead
to contextual processes. They refer to experimental work according to which
cortical oscillations may propagate in the cortex as if they were waves; and to
simulations of the mammalian brain which show the presence of interference in
the cortex.
3. Bohmian programmes of quantum cognition
We already mentioned briefly above that the physicist David Bohm speculated
early about strong quantum cognition in his 1951 textbook. At that time he was
thinking within the usual interpretation of quantum theory, and the analogies he
drew attention to then reflect this. As is well known, Bohms key long-term aim
was to understand quantum theory better, and this led him to develop a number of
different alternative schemes. Given his early intuition that quantum theory and
thought are analogous, it is not surprising that he applied the new ideas arising
from his various quantum schemes to describing the mind.
In 1952 Bohm published two articles inPhysical Review where he proposed
(following deBroglies earlier ideas) that an electron is a particle guided by a field.
In later work with Basil Hiley, Bohm emphasized that this field does not push andpull the particle mechanically but rather in-forms its energy. Thus, Bohm and
Hiley argued, the key new ontological feature of quantum theory is the existence
of objective and active information at the quantum level. Bohm extended this
model to include higher-levels of information, so that cognitive informational
processes could be connected to quantum information, which in turn could control
neurophysiological processes in, say, synapses. This line of research has been
developed by e.g. Pylkknen and Hiley. They propose that the approach enables
new ways of understanding such key philosophical problems as mental causation,
intentionality and even consciousness.
In Bohms active information scheme it is assumed that quantum theory
needs to be extended into a hierarchy of levels of active information, where the
human mind, for example, involves not only the lower levels, but also the more
subtle levels (Bohm claimed that such an extension of quantum theory is not
arbitrary, but natural from the physical and mathematical point of view). Some
of these levels are at the manifest, classical level while others are more subtle.
In perception, information encoded in manifest levels (e.g. in the form of printed
words) is carried toward the more subtle levels in the nervous system, where the
meaning of the information is apprehended. Such apprehension of meaning is an
activity, which crucially involves the organization of the lower levels of
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information. There is thus a two-way traffic between manifest and subtle levels.
It is in this way that we can understand how mind (understood as involving very
subtle physical levels) can influence the more manifest aspects of the physical
domain (e.g. the movement of the hand). In other words, we obtain a new way of
understanding mental causation.
One key idea is that the more subtle, physical (mental) levels are
influenced by and can also influence the lower, manifest levels. Mind is not
floating free from the quantum and classical levels, but can influence these latter,
thus providing a new way of understanding mental causation. The level of
quantum information is especially important in providing the missing link between
the traditional categories of physical and mental. Of course, it is a major unsolved
problem in the Bohm scheme what exactly is meant by the subtle levels. It
seems that Bohm meant both complex neurophysiological processes (alreadydescribed in cognitive neuroscience), and some subtle quantum and super-
quantum effects taking place in the brain but not yet discovered. Thus this is
currently a heavily speculative scheme which needs much further critical
examination and development. Yet, in my view, it has some advantages over the
other schemes of strong quantum cognition (see Hiley & Pylkknen 2005). It can
be argued that the Bohm-Hiley ontological interpretation provides currently the
best ontological scheme for quantum theory, and we need a clear quantum
ontology to tackle in a quantum-theoretical way the mind-matter problem, also
known as the ontological problem (Churchland 2013).
In the early 1960s Bohm began to seek a more general scheme in which
one could bring quantum theory and relativity together. This framework became
known as the implicate order. The implicate order refers to holistic phenomena,where, for example, information about the whole is enfolded in each region (as in
the movement of lights waves, which can be recorded in a hologram). Applied to
the universe, this suggests that the universe is a movement in which a holistic
order, the implicate order prevails thus the universe is holomovement. At each
moment a three-dimensional explicate order unfolds from the holomovement, only
to enfold back in the next moment. This process of unfoldment and enfoldment
takes place so rapidly that we do not see it but instead typically perceive an
enduring three-dimensional reality of macroscopic objects.
Bohm proposed that the implicate order is fundamental and general, and
also prevails in biological and psychological phenomena. For example, the
conscious experience of listening to music can be understood in terms of the
implicate order. A symphony involves a movement in which a total order builds
up and grows. At each moment we are most explicitly aware of certain tones,
while the previously explicate tones are experienced as enfolded, actively
transforming structures; our experience also involves an anticipation the future
tones. Bohm thus provided a new way of thinking and modeling a central issue in
phenomenology, namely time consciousness. This has been discussed in some
detail by Pylkknen (2007, ch 5). Such an application of the implicate order to
describe phenomenal experience can be seen as an instance of weak quantum
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cognition, as one is using a theoretical scheme inspired by quantum theory while
not claiming that phenomenal experience is literally a quantum phenomenon.
4. Discussion
Strong programs of quantum cognition typically underline the importance of
physical considerations when trying to understand they mind. However, this need
not imply the assumption that mental processes are reduced to some quantum
mechanical processes. []
References
Aerts, D. Quantum structure in cognition, Journal of Mathematical Psychology 53
(2009) 314-348.
Atmanspacher, Harald, (2011) Quantum Approaches to Consciousness, The
Stanford Encyclopedia of Philosophy, Edward N. Zalta (ed.), URL =
Atmanspacher, H., Rmer, H., and Walach, H. (2002). Weak quantum theory:
Complementarity and entanglement in physics and beyond. Foundations of
Physics 32, 379406.
Ball, P. (2011) The dawn of quantum biology,Nature 474, pp. 272-274).
Barros, J.A. & Suppes, P. Quantum mechanics, interference and the brain, Journal
of Mathematical Psychology 53 (2009) 306-313.
Churchland, P. (2013) Matter and Consciousness. 3rd edition. Cambridge,
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Globus, G. (2003) Quantum Closures and Disclosures: Thinking-together
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Pothos, M & Busemeyer J. R. (2013) Can quantum probability provide a new
direction for cognitive modeling?Behavioral and Brain Science
Pylkknen, P. (2004) Can quantum analogies help us to understand the process of
thought?, in G. Globus, K. Pribram and G. Vitiello (eds.) Being and Brain. At the
Boundary between Science, Philosophy, Language and Arts, pp. 167-197.
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