Cosmos (27 page)

Rest your neck on a log. Your head goes back. Then you can see only the sky. No hills, no trees, no hunterfolk, no campfire. Just sky. Sometimes I feel I may fall up into the sky. If the stars
are campfires, I would like to visit those other hunterfolk—the ones who wander. Then I feel good about falling up. But if the stars are holes in a skin, I become afraid. I don’t want to fall up through a hole and into the flame of power
.

I wish I knew which was true. I don’t like not knowing
.

I do not imagine that many members of a hunter/gatherer group had thoughts like these about the stars. Perhaps, over the ages, a few did, but never all these thoughts in the same person. Yet, sophisticated ideas are common in such communities. For example, the !Kung
^*
Bushmen of the Kalahari Desert in Botswana have an explanation for the Milky Way, which at their latitude is often overhead. They call it “the backbone of night,” as if the sky were some great beast inside which we live. Their explanation makes the Milky Way useful as well as understandable. The !Kung believe the Milky Way holds up the night; that if it were not for the Milky Way, fragments of darkness would come crashing down at our feet. It is an elegant idea.

Metaphors like those about celestial campfires or galactic backbones were eventually replaced in most human cultures by another idea: The powerful beings in the sky were promoted to gods. They were given names and relatives, and special responsibilities for the cosmic services they were expected to perform. There was a god or goddess for every human concern. Gods ran Nature. Nothing could happen without their direct intervention. If they were happy, there was plenty of food, and humans were happy. But if something displeased the gods—and sometimes it took very little—the consequences were awesome: droughts, storms, wars, earthquakes, volcanoes, epidemics. The gods had to be propitiated, and a vast industry of priests and oracles arose to make the gods less angry. But because the gods were capricious, you could not be sure what they would do. Nature was a mystery. It was hard to understand the world.

Little remains of the Heraion on the Aegean isle of Samos, one of the wonders of the ancient world, a great temple dedicated to Hera, who began her career as goddess of the sky. She was the patron deity of Samos, playing the same role there as Athena did in Athens. Much later she married Zeus, the chief of the Olympian gods. They honeymooned on Samos, the old stories tell us. The Greek religion explained that diffuse band of light in the night sky as the milk of Hera, squirted from her breast across the heavens, a legend that is the origin of the phrase Westerners still use—the
Milky Way. Perhaps it originally represented the important insight that the sky nurtures the Earth; if so, that meaning seems to have been forgotten millennia ago.

We are, almost all of us, descended from people who responded to the dangers of existence by inventing stories about unpredictable or disgruntled deities. For a long time the human instinct to understand was thwarted by facile religious explanations, as in ancient Greece in the time of Homer, where there were gods of the sky and the Earth, the thunderstorm, the oceans and the underworld, fire and time and love and war; where every tree and meadow had its dryad and maenad.

For thousands of years humans were oppressed—as some of us still are—by the notion that the universe is a marionette whose strings are pulled by a god or gods, unseen and inscrutable. Then, 2,500 years ago, there was a glorious awakening in Ionia: on Samos and the other nearby Greek colonies that grew up among the islands and inlets of the busy eastern Aegean Sea.
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Suddenly there were people who believed that everything was made of atoms; that human beings and other animals had sprung from simpler forms; that diseases were not caused by demons or the gods; that the Earth was only a planet going around the Sun. And that the stars were very far away.

This revolution made Cosmos out of Chaos. The early Greeks had believed that the first being was Chaos, corresponding to the phrase in Genesis in the same context, “without form.” Chaos created and then mated with a goddess called Night, and their offspring eventually produced all the gods and men. A universe created from Chaos was in perfect keeping with the Greek belief in an unpredictable Nature run by capricious gods. But in the sixth century
B.C
., in Ionia, a new concept developed, one of the great ideas of the human species. The universe is knowable, the ancient Ionians argued, because it exhibits an internal order: there are regularities in Nature that permit its secrets to be uncovered. Nature is not entirely unpredictable; there are rules even she must obey. This ordered and admirable character of the universe was called Cosmos.

But why Ionia, why in these unassuming and pastoral landscapes, these remote islands and inlets of the Eastern Mediterranean? Why not in the great cities of India or Egypt, Babylonia, China or Mesoamerica? China had an astronomical tradition millennia old; it invented paper and printing, rockets, clocks, silk,
porcelain, and ocean-going navies. Some historians argue it was nevertheless too traditionalist a society, too unwilling to adopt innovations. Why not India, an extremely rich, mathematically gifted culture? Because, some historians maintain, of a rigid fascination with the idea of an infinitely old universe condemned to an endless cycle of deaths and rebirths, of souls and universes, in which nothing fundamentally new could ever happen. Why not Mayan and Aztec societies, which were accomplished in astronomy and captivated, as the Indians were, by large numbers? Because, some historians declare, they lacked the aptitude or impetus for mechanical invention. The Mayans and the Aztecs did not even—except for children’s toys—invent the wheel.

The Ionians had several advantages. Ionia is an island realm. Isolation, even if incomplete, breeds diversity. With many different islands, there was a variety of political systems. No single concentration of power could enforce social and intellectual conformity in all the islands. Free inquiry became possible. The promotion of superstition was not considered a political necessity. Unlike many other cultures, the Ionians were at the crossroads of civilizations, not at one of the centers. In Ionia, the Phoenician alphabet was first adapted to Greek usage and widespread literacy became possible. Writing was no longer a monopoly of the priests and scribes. The thoughts of many were available for consideration and debate. Political power was in the hands of the merchants, who actively promoted the technology on which their prosperity depended. It was in the Eastern Mediterranean that African, Asian, and European civilizations, including the great cultures of Egypt and Mesopotamia, met and cross-fertilized in a vigorous and heady confrontation of prejudices, languages, ideas and gods. What do you do when you are faced with several different gods each claiming the same territory? The Babylonian Marduk and the Greek Zeus was each considered master of the sky and king of the gods. You might decide that Marduk and Zeus were really the same. You might also decide, since they had quite different attributes, that one of them was merely invented by the priests. But if one, why not both?

And so it was that the great idea arose, the realization that there might be a way to know the world without the god hypothesis; that there might be principles, forces, laws of nature, through which the world could be understood without attributing the fall of every sparrow to the direct intervention of Zeus.

China and India and Mesoamerica would, I think, have tumbled to science too, if only they had been given a little more time.
Cultures do not develop with identical rhythms or evolve in lock-step. They arise at different times and progress at different rates. The scientific world view works so well, explains so much and resonates so harmoniously with the most advanced parts of our brains that in time, I think, virtually every culture on the Earth, left to its own devices, would have discovered science. Some culture had to be first. As it turned out, Ionia was the place where science was born.

Between 600 and 400
B.C
., this great revolution in human thought began. The key to the revolution was the hand. Some of the brilliant Ionian thinkers were the sons of sailors and farmers and weavers. They were accustomed to poking and fixing, unlike the priests and scribes of other nations, who, raised in luxury, were reluctant to dirty their hands. They rejected superstition, and they worked wonders. In many cases we have only fragmentary or secondhand accounts of what happened. The metaphors used then may be obscure to us now. There was almost certainly a conscious effort a few centuries later to suppress the new insights. The leading figures in this revolution were men with Greek names, largely unfamiliar to us today, but the truest pioneers in the development of our civilization and our humanity.

The first Ionian scientist was Thales of Miletus, a city in Asia across a narrow channel of water from the island of Samos. He had traveled in Egypt and was conversant with the knowledge of Babylon. It is said that he predicted a solar eclipse. He learned how to measure the height of a pyramid from the length of its shadow and the angle of the Sun above the horizon, a method employed today to determine the heights of the mountains of the Moon. He was the first to prove geometric theorems of the sort codified by Euclid three centuries later—for example, the proposition that the angles at the base of an isosceles triangle are equal. There is a clear continuity of intellectual effort from Thales to Euclid to Isaac Newton’s purchase of the
Elements of Geometry
at Stourbridge Fair in 1663 (p. 68), the event that precipitated modern science and technology.

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.
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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:

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 made war on his neighbors; he quite rightly feared invasion. So he surrounded his capital city with a massive wall, about six kilometers long, whose remains stand to this day. To carry water from a distant spring through the fortifications, he ordered a great tunnel built. A kilometer long, it pierces a mountain. Two cuttings were dug from either end which met almost perfectly in the middle. The project took about fifteen years to complete, a testament to the civil engineering of the day and an indication of the extraordinary practical capability of the Ionians. But there is another and more ominous side to the enterprise: it was built in part by slaves in chains, many captured by the pirate ships of Polycrates.