MATHEMATICIAN, PHYSICIST

Life
One of the Seven Sages of Ancient Greece, and chronologically the first of the Greek philosophers, Thales of Miletus is considered the founder of European philosophy and science. He was born in Miletus, in Asia Minor; his father being called Hexamios and his mother Cleoboulene. The family was of Boeotian origin, and Thales considered himself a descendant of Cadmus and Agenor.


Work
Thales was the first to abandon a blind empiricism and turn to a theoretical investigation of causes. This is his most important contribution to the development of a universal philosophical and scientific spirit. He attempted to explain things, and give them a justification in theory. He held water to be the prime origin of all things, positing that every kind of matter is produced through the transformation of this uncreated and imperishable elemental substance. He made a number of purely scientific discoveries in geometry, astronomy and physics; he developed his own philosophical system; and he took part in the political life of Ionia. He also built large engineering works, devised instruments for calculating distances, and travelled widely for both commercial and scientific purposes.

In geometry, Thales is credited with 5 theorems: 1) that a circle is bisected by its diameter; 2) that the angles at the base of a triangle having two sides of equal length are equal; 3) that opposite angles of intersecting straight lines are equal; 4) that the angle inscribed in a semicircle is a right angle; and 5) that a triangle is determined if its base and the angles relative to the base are determined.

Thales is also credited with the discovery that a piece of amber when rubbed attracts small light particles. This opened a whole new window onto the unknown universe, and made Thales the father of the science of electricity that would not be fully understood and exploited for another 24 centuries.

A number of wise sayings have been ascribed to Thales, including maxims like: "The most beautiful thing is the world itself, for it is God's handiwork", "One should always be as mindful of absent friends as of those who are present", "One should not cultivate a fine appearance, but comeliness in his manner of living", "Do not seek to enrich yourself in unseemly fashion, and take care that your words do not earn you the enmity of those who have trusted you". When asked whether someone who is unjust might escape the notice of the gods, Thales replied that even one's thoughts do not escape the notice of the gods. And when, having stated that there is no difference between life and death, he was asked why he himself did not choose death die, he replied that it was precisely because there was no difference.

His principal writings include: "Naval astrology", "On origins", "On changes", "On the equinox", "Meteorology". None of the original texts have survived, but there are commentaries in a number of sources, including Apollodorus, Suidas, Callimachus, Herodotus, Plato and Aristotle.