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Thales of Miletus

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Thales of Miletus
Thales of Miletus

Thales of Miletus (c. 624 - 546 B.C.) was an early Pre-Socratic philosopher, mathematician and astronomer from the Greek city of Miletus in Ionia (modern-day Turkey). He was one of the so-called Seven Sages of Greece, and many regard him as the first philosopher in the Western tradition.

He was the founder of the Milesian School of natural philosophy, and the teacher of Anaximander. He was perhaps the first subscriber to Materialist and Naturalism in trying to define the substance or substances of which all material objects were composed, which he identified as water.

His innovative search for a universality in the disciplines of mathematics, astronomy and philosophy have earned him the label the "first scientist".


Thales (pronounced THAY-lees) was born in the Greek city of Miletus (on the Ionian coast of modern-day Turkey) in about 624 or 625 B.C. (an estimate based on his age at death). The 3rd Century A.D. historian Diogenes Laėrtius reported that his parents were Examyas and Cleobulina of the noble Milesian family of Thelidae (and descended from Agenor and Cadmus of ancient Thebes, Greece), although other sources suggest that his parents may have been Phoenician (from the modern-day region of Lebanon, Israel and Syria).

Details of his life are sketchy and often contradictory. Some reports suggest that he married and had a son, Cybisthus (or Cybisthon) or possibly adopted a nephew of the same name, while other reports suggest that he never married. Some say that he left no writings; others that he wrote at least two works, "On the Solstice" and "On the Equinox" (neither have survived). Some anecdotes suggest that Thales was involved in business and politics, and at one point bought up all the olive presses in Miletus after predicting a good harvest for a particular year (either to make money or merely to demonstrate that he could use his intelligence to enrich himself if he had wanted to).

His involvement in local politics is also rather anecdotal in nature, but Thales apparently impressed both sides of the ongoing conflict between the Lydians, Medes and Persians over the fate of the region of Ionia, when he predicted an eclipse of the sun which brought fighting to a standstill. He was also reportedly involved in the negotiations which followed the hostilities, and managed to obtain favourable terms for Miletus.

Thales is said to have died of dehydration while watching a gymnastics contest in 546 or 547 B.C., at the age of 78 (although other reports have him living to the age of 90).

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In retrospect is is difficult to separate history from legend, but he is usually considered one of the Seven Sages or Seven Wise Men of ancient Greece, a group of 7th and early 6th Century B.C. philosophers, statesmen and law-givers who became renowned in the following centuries for their wisdom. The aphorism "Know thyself" has been attributed to Thales (as well as to at least six other ancient Greek sages). Much of what we known of Thales' philosophy has come down to us from Aristotle and so may be somewhat distorted by Aristotle's own views. Some sources say that he left no writings; others that he wrote at least two works, "On the Solstice" and "On the Equinox" (neither of which have survived).

The early Pre-Socratic philosophers (of which Thales was one of the very first) tried to define the substance or substances of which all material objects were composed (as do modern scientists even today, hence Thales is sometimes described as the first scientist). He searched for the "physis" (or nature) of objects that cause them to behave in their characteristic way. He was one of the first Western philosophers who attempted to find naturalistic explanations of the world (Naturalism or Materialism) without reference to supernatural or mythological explanations, such as the Greek anthropomorphic gods and heroes. He explained earthquakes, for example, by hypothesizing that the Earth floats on water and that earthquakes occur when the Earth is rocked by waves.

His most famous belief was his cosmological doctrine that water was the first principle (roughly equivalent to Anaximenes' later idea that everything in the world was composed of air). He claimed that water was the origin of all things, that from which all things emerge and to which they return, and moreover that all things ultimately are water. He probably drew this conclusion from seeing moist substances turn into air, slime and earth, and he clearly viewed the Earth as solidifying from the water on which it floated and which surrounded it.

While considering the effects of magnetism and static electricity, he concluded that the power to move other things without the mover itself changing was a characteristic of "life", so that a magnet and amber must therefore be alive in some way (in that they have animation or the power to act). If so, he argued, there is no difference between the living and the dead. If all things were alive, they must also have souls or divinities (a natural belief of his time), and the end result of this argument was an almost total removal of mind from substance, opening the door to an innovative non-divine principle of action.

Thales recognized a single transcendental God (Monism), who has neither beginning nor end, but who expresses himself through other gods (Polytheism). His idea of justice included both the letter of the law and the spirit of the law (e.g. adultery and perjury about it in court are equally bad). He had some common sense moral advice: that we should expect the same support from our children that we give to our parents; that we should not let talk influence us against those we have come to trust; and that we should not do ourselves that for which we blame others. He believed that a happy man was one who was "healthy in body, resourceful in soul and of a readily teachable nature".

His political views were generally in favour of a benign tyranny, rather than democracy (which most thinkers of his time distrusted as an inefficient and unreliable system). He believed that men were naturally better than women, and that Greeks were better than barbarians (non-Greeks).

Thales was known for his theoretical and practical understanding (and innovative use) of geometry, especially triangles. He established what has become known as Thales' Theorem, whereby if a triangle is drawn within a circle with the long side as a diameter of the circle then the opposite angle will always be a right angle (as well as some other related properties derived from this).

He was also an important innovator in astronomy, and he had an effective theory of the path of the sun from solstice to solstice and supposedly correctly predicted a solar eclipse. Some sources have attributed him with the "discovery" of the seasons of the year and the 365-day year (consistent with his determination of the solstices). While this may be an exaggeration, his questioning approach to the understanding of heavenly phenomena arguably marked the real beginning of Greek astronomy.

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See the additional sources and recommended reading list below, or check the philosophy books page for a full list.


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