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  • Thales

    For other uses, see Thales (disambiguation).

    Thales of Miletus (/eliz/; Greek: ( -), Thals; c. 624 c. 546 BC) was a pre-SocraticGreek philosopher from Miletus in Asia Minor, and oneof the Seven Sages of Greece. Many, most notablyAristotle, regard him as the rst philosopher in the Greektradition.[1] Aristotle reported Thales hypothesis aboutthe nature of matter that the originating principle ofnature was a single material substance: water.According to Bertrand Russell, Western philosophy be-gins with Thales.[2] Thales attempted to explain natu-ral phenomena without reference to mythology and wastremendously inuential in this respect. Almost all ofthe other Pre-Socratic philosophers follow him in at-tempting to provide an explanation of ultimate substance,change, and the existence of the world without referenceto mythology. Those philosophers were also inuentialand eventually Thales rejection of mythological expla-nations became an essential idea for the scientic revolu-tion. He was also the rst to dene general principles andset forth hypotheses, and as a result has been dubbed theFather of Science, though it is argued that Democritusis actually more deserving of this title.[3][4]

    In mathematics, Thales used geometry to solve problemssuch as calculating the height of pyramids and the dis-tance of ships from the shore. He is credited with therst use of deductive reasoning applied to geometry, byderiving four corollaries to Thales Theorem. As a result,he has been hailed as the rst true mathematician and isthe rst known individual to whom a mathematical dis-covery has been attributed.[5]

    1 LifeThe current historical consensus is that Thales was bornin the city of Miletus around the mid 620s BC. Miletuswas an ancient Greek Ionian city on the western coast ofAsia Minor (in what is today Aydin Province of Turkey),near the mouth of the Maeander River.

    1.1 BackgroundThe dates of Thales life are not exactly known, but areroughly established by a few dateable events mentioned inthe sources. According to Herodotus (and determinationby modern methods) Thales predicted the solar eclipse of

    May 28, 585 BC.[6] Diogenes Lartius quotes the chron-icle of Apollodorus of Athens as saying that Thales diedat the age of 78 in the 58th Olympiad (548545 BC),and attributes his death to heat stroke while watching theGames.Diogenes Lartius states that (according to Herodotusand Douris and Democritus") Thales parents were Ex-amyes and Cleobuline, then traces the family line backto Cadmus, a mythological Phoenician prince of Tyre.Diogenes then delivers conicting reports: one thatThales married and either fathered a son (Cybisthus orCybisthon) or adopted his nephew of the same name;the second that he never married, telling his mother asa young man that it was too early to marry, and as anolder man that it was too late. Plutarch had earlier toldthis version: Solon visited Thales and asked him why heremained single; Thales answered that he did not like theidea of having to worry about children. Nevertheless, sev-eral years later, anxious for family, he adopted his nephewCybisthus.[7]

    Thales involved himself in many activities, taking the roleof an innovator. Some say that he left no writings, otherssay that he wrote On the Solstice and On the Equinox. (Nowriting attributed to him has survived.) Diogenes Lar-tius quotes two letters from Thales: one to Pherecydesof Syros oering to review his book on religion, and oneto Solon, oering to keep him company on his sojournfrom Athens. Thales identies the Milesians as Atheniancolonists.[8]

    1.2 Business

    An olive mill and an olive press dating from Roman times inCapernaum, Israel.


  • 2 1 LIFE

    Several anecdotes suggest that Thales was not solely athinker but was also involved in business and politics.One story recounts that he bought all the olive presses inMiletus after predicting the weather and a good harvestfor a particular year. In another version of the same story,Aristotle explains that Thales reserved presses ahead oftime at a discount only to rent them out at a high pricewhen demand peaked, following his predictions of a par-ticularly good harvest. This rst version of the storywould constitute the rst creation and use of futures,whereas the second version would be the rst creation anduse of options. Aristotle explains that Thales objectivein doing this was not to enrich himself but to prove to hisfellowMilesians that philosophy could be useful, contraryto what they thought.[9]

    1.3 PoliticsThales political life had mainly to do with the involve-ment of the Ionians in the defense of Anatolia against thegrowing power of the Persians, who were then new to theregion. A king had come to power in neighboring Lydia,Croesus, who was somewhat too aggressive for the size ofhis army. He had conquered most of the states of coastalAnatolia, including the cities of the Ionians. The story istold in Herodotus.[10]

    The Lydians were at war with the Medes, a remnant ofthe rst wave of Iranians in the region, over the issue ofrefuge the Lydians had given to some Scythian soldiersof fortune inimical to the Medes. The war endured forve years, but in the sixth an eclipse of the Sun (men-tioned above) spontaneously halted a battle in progress(the Battle of Halys).

    Total eclipse of the Sun

    It seems that Thales had predicted this solar eclipse. TheSeven Sages were most likely already in existence, asCroesus was also heavily inuenced by Solon of Athens,

    another sage. Whether Thales was present at the battle isnot known, nor are the exact terms of the prediction, butbased on it the Lydians and Medes made peace immedi-ately, swearing a blood oath.The Medes were dependencies of the Persians underCyrus. Croesus now sided with the Medes against thePersians and marched in the direction of Iran (with farfewer men than he needed). He was stopped by the riverHalys, then unbridged. This time he had Thales with him,perhaps by invitation. Whatever his status, the king gavethe problem to him, and he got the army across by digginga diversion upstream so as to reduce the ow, making itpossible to ford the river. The channels ran around bothsides of the camp.The two armies engaged at Pteria in Cappadocia. As thebattle was indecisive but paralyzing to both sides, Croesusmarched home, dismissed his mercenaries and sent emis-saries to his dependents and allies to ask them to dispatchfresh troops to Sardis. The issue became more pressingwhen the Persian army showed up at Sardis. DiogenesLaertius[11] tells us that Thales gained fame as a coun-selor when he advised the Milesians not to engage in asymmachia, a ghting together, with the Lydians. Thishas sometimes been interpreted as an alliance, but a rulerdoes not ally with his subjects.Croesus was defeated before the city of Sardis by Cyrus,who subsequently spared Miletus because it had taken noaction. Cyrus was so impressed by Croesus wisdom andhis connection with the sages that he spared him and tookhis advice on various matters.The Ionians were now free. Herodotus says that Thalesadvised them to form an Ionian state; that is, a bouleu-terion (deliberative body) to be located at Teos in thecenter of Ionia. The Ionian cities should be demoi, ordistricts. Miletus, however, received favorable termsfrom Cyrus. The others remained in an Ionian League of12 cities (excluding Miletus now), and were subjugatedby the Persians.While Herodotus reported that most of his fellow Greeksbelieve that Thales did divert the river Halys to assistKing Croesus military endeavors, he himself nds itdoubtful.[12]

    1.4 Sagacity

    Diogenes Laertius[13] tells us that the Seven Sages werecreated in the archonship of Damasius at Athens about582 BC and that Thales was the rst sage. The same story,however, asserts that Thales emigrated to Miletus. Thereis also a report that he did not become a student of natureuntil after his political career. Much as we would like tohave a date on the seven sages, wemust reject these storiesand the tempting date if we are to believe that Thales wasa native of Miletus, predicted the eclipse, and was withCroesus in the campaign against Cyrus.

  • 2.1 Water as a rst principle 3

    The Ionic Stoa on the Sacred Way in Miletus

    Thales received instruction from an Egyptian priest. Itwas fairly certain that he came from awealthy, establishedfamily, in a class which customarily provided higher edu-cation for their children. Moreover, the ordinary citizen,unless he was a seafaring man or a merchant, could notaord the grand tour in Egypt, and did not consort withnoble lawmakers such as Solon.Thales participated in some games, most likelyPanhellenic, in which he won a bowl twice. Hededicated it to Apollo at Delphi. As he was not known tohave been athletic, his event was probably declamation,and it may have been victory in some specic phase ofthis event that led to his sagacious designation.

    2 TheoriesThe Greeks often invoked idiosyncratic explanationsof natural phenomena with reference to the will ofanthropomorphic gods and heroes. Instead, Thales aimedto explain natural phenomena via rational hypotheses thatreferenced natural processes themselves. For example,rather than assuming that earthquakes were the result ofsupernatural whims Thales explained them by hypothe-sizing that the Earth oats on water and that earthquakesoccur when the Earth is rocked by waves.Thales was a hylozoist (one who thinks that matter isalive).[14] That interpretation by later commentatorsthat Thales treated matter as being alivemay have beensubstituted for his thinking that the properties of na-ture arise directly from material processes. The lat-ter thesis is more consistent with modern ideas of howproperties arise as emergent characteristics of thosecomplex systems involved in the processes of evolutionand developmental change.Thales, according to Aristotle, asked