Cosmos - Carl Sagan [94]
Thales attempted to understand the world without invoking the intervention of the gods. Like the Babylonians, he believed the world to have once been water. To explain the dry land, the Babylonians added that Marduk had placed a mat on the face of the waters and piled dirt upon it.* Thales held a similar view, but, as Benjamin Farrington said, “left Marduk out.” Yes, everything was once water, but the Earth formed out of the oceans by a natural process—similar, he thought, to the silting he had observed at the delta of the Nile. Indeed, he thought that water was a common principle underlying all of matter, just as today we might say the same of electrons, protons and neutrons, or of quarks. Whether Thales’ conclusion was correct is not as important as his approach: The world was not made by the gods, but instead was the work of material forces interacting in Nature. Thales brought back from Babylon and Egypt the seeds of the new sciences of astronomy and geometry, sciences that would sprout and grow in the fertile soil of Ionia.
Very little is known about the personal life of Thales, but one revealing anecdote is told by Aristotle in his Politics:
[Thales] was reproached for his poverty, which was supposed to show that philosophy is of no use. According to the story, he knew by his skill [in interpreting the heavens] while it was yet winter that there would be a great harvest of olives in the coming year; so, having a little money, he gave deposits for the use of all the olive-presses in Chios and Miletus, which he hired at a low price because no one bid against him. When the harvest time came, and many were wanted all at once, he let them out at any rate which he pleased and made a quantity of money. Thus he showed the world philosophers can easily be rich if they like, but that their ambition is of another sort.
He was also famous as a political sage, successfully urging the Milesians to resist assimilation by Croesus, King of Lydia, and unsuccessfully urging a federation of all the island states of Ionia to oppose the Lydians.
Anaximander of Miletus was a friend and colleague of Thales, one of the first people we know of to do an experiment. By examining the moving shadow cast by a vertical stick he determined accurately the length of the year and the seasons. For ages men had used sticks to club and spear one another. Anaximander used one to measure time. He was the first person in Greece to make a sundial, a map of the known world and a celestial globe that showed the patterns of the constellations. He believed the Sun, the Moon and the stars to be made of fire seen through moving holes in the dome of the sky, probably a much older idea. He held the remarkable view that the Earth is not suspended or supported from the heavens, but that it remains by itself at the center of the universe; since it was equidistant from all places on the “celestial sphere,” there was no force that could move it.
He argued that we are so helpless at birth that, if the first human infants had been put into the world on their own, they would immediately have died. From this Anaximander concluded that human beings arose from other animals with more self-reliant newborns: He proposed the spontaneous origin of life in mud, the first animals being fish covered with spines. Some descendants of these fishes eventually abandoned the water and moved to dry land, where they evolved into other animals by the transmutation of one form into another. He believed in an infinite number of worlds, all inhabited, and all subject to cycles of dissolution and regeneration. “Nor,” as Saint Augustine ruefully complained, “did he, any more than Thales, attribute the cause of all this ceaseless activity to a divine mind.”
In the year 540 B.C. or thereabouts, on the island of Samos, there came to power a tyrant named Polycrates. He seems to have started as a caterer and then gone on to international piracy. Polycrates was a generous patron of the arts, sciences and engineering. But he oppressed his own people; he