blimix | Thales

Thales is the earliest known philosopher. He gave natural science credibility, kick-starting the use of rational thought to explain the world, when he correctly predicted a solar eclipse in 585 BCE, using Babylonian records of eclipses. He showed that we didn't have to dismiss the questions "Why?" and "How?" with "Oh, well, it's just the random whims of the gods." (Sources: Herodotus, Diogenes Laertius)

Thales brought geometry to Greece from Egypt. He applied it to stuff like measuring the pyramids and the distance of ships at sea. (Source: Diogenes Laertius)

When King Croesus attacked the Persians (an extremely stupid move, BTW), his army marched to the river Halys. Thales had a trench dug in a semicircle around the army, connecting to the river both upstream and downstream of the army, thus diverting most of its water. With the river now effectively behind it, the army marched on. (Source: Diogenes Laertius citing Appolodorus)

Thales secured a monopoly on apple presses and made lots of money, showing that philosophers "can easily be rich if they like, but that their ambition is of another sort." (Source: Aristotle) Too cool.

Thales founded the Milesian school of thought, which attempted to explain the universe in terms of matter (and all change in terms of water). They had some strange ideas, many differing from thinker to thinker, but they nailed this one: "Nothing is either generated or annihilated." (i.e., "Matter can neither be created nor destroyed.") (Source: Aristotle)

(And on the subjects of Milesian natural philosophy, I'd like to mention Thales' pupil Anaximander. He decided that the heavenly bodies weren't revolving around the Earth, and the Earth wasn't floating on a bed of water or anything else; rather, the Earth was spinning freely in space, drawn to remain at the center of the universe by its own weight. He also said that life, (which began in moisture, as Thales had taught), had followed a course of evolution. Eat your heart out, Charles Darwin.)

All my information here is from Milton C. Nahm, Selections from Early Greek Philosophy, 4th edition (Prentice Hall).