Read an Excerpt
IONIA: THE FIRST PHYSICISTS
The site of ancient Miletus is on the Aegean coast of Turkey south of Izmir, the Greek Smyrna. When I first visited Miletus, in April 1961, it was completely deserted except for a goatherd and his flock, whose resonant bells broke the silence enveloping the ruins through which I wandered, the great Hellenistic theater, the cavernous Roman baths, the colonnaded way that led down to the Lion Port and its surrounding shops and warehouses, once filled with goods from Milesian colonies as far afield as Egypt and the Pontus. Its buildings were now utterly devastated and partly covered with earth, from which the first flowers of spring were emerging, blood-red poppies contrasting with the pale white marble remnants of the dead city.
The site has been under excavation since the late nineteenth century, so that all of its surviving monuments have been unearthed and to some extent restored, though its ancient harbor, the Lion Port, has long been silted up, leaving Miletus marooned miles from the sea. The entrance to the port is still guarded by the marble statues of the two couchant lions from which it took its name, though they are now half-buried in alluvial earth, symbols of the illustrious city that Herodotus called “the glory of Ionia.” The Greek geographer Strabo writes that “many are the achievements of this city, but the greatest are the number of its colonizations, for the Euxine Pontus [Black Sea] has been colonized everywhere by these people, as has the Propontis [Sea of Marmara] and several other regions.”
Excavations have revealed that the earliest remains in Miletus date from the second half of the sixteenth century B.C., when colonists from Minoan Crete are believed to have established a settlement here. A second colony was founded on the same site during the mass migration of Greeks early in the first millennium b.c., when they left their homeland in mainland Greece and migrated eastward across the Aegean, settling on the coast of Asia Minor and its offshore islands. Three Greek tribes were involved in this migration—the Aeolians to the north, the Ionians in the center, and the Dorians in the south—and together they produced the first flowering of Greek culture. The Aeolians gave birth to the lyric poet Sappho; the Ionians to Homer and the natural philosophers Thales, Anaximander, and Anaximenes; and the Dorians to Herodotus, the “Father of History.”
Herodotus, describing this migration in Book I of his Histories, writes that the Ionians ended up with the best location in Asia Minor, for they “had the good fortune to establish their settlements in a region which enjoys a better climate than any we know of.” Pausanias, in his Description of Greece, written in the second century a.d. remarks, “The Ionian countryside has excellently tempered seasons, and its sanctuaries are unrivalled.” He goes on to say that “the wonders of Ionia are numerous, and not much short of the wonders of Greece.”
The Ionian colonies soon organized themselves into a confederation called the Panionic League. This comprised one city each on the islands of Chios and Samos and ten on the mainland of Asia Minor opposite, namely, Phocaea, Clazomenae, Erythrae, Teos, Lebedus, Colophon, Ephesus, Priene, Myus, and Miletus. The confederation, also known as the Dodecapolis, had its common meeting place at the Panionium, on the mainland opposite Samos. The Ionians also met annually on the island of Delos, the legendary birthplace of Apollo, their patron deity. There they honored the god in a festival described in the Homeric Hymn addressed to Delian Apollo:
Yet in Delos do you most delight your heart; for the long-robed Ionians gather in your honor with their children and shy wives. Mindful, they delight you with boxing and dancing and song, so often as they hold their gathering. A man would say that they are deathless and unaging if he should come upon the Ionians so met together. For he would see the graces of them all, and would be pleased in heart gazing at the well-girded women and the men with their swift ships and great renown.
Miletus greatly surpassed all of the other Ionian cities in its maritime ventures and commerce, founding its first colonies in the eighth century B.C. on the shores of the Black Sea. During the next two centuries Miletus was far more active in colonization than any other city-state in the Greek world, founding a total of thirty cities around the Black Sea and its approaches in the Hellespont and the Sea of Marmara. Miletus also had a trading station at Naucratis, the Greek emporium on the Nile delta founded circa 650 B.C. Meanwhile other Greek cities had established colonies around the western shores of the Mediterranean, the densest region of settlement being in southern Italy and Sicily, which became known as Magna Graecia, or Great Greece.
The Ionian cities eventually lost their freedom, first to the Lydians and then to the Persians, whose attempt to conquer Greece ended with their defeat by the Greek allies at the battle of Plataea in 479 B.C. The Persian king Xerxes took his revenge for this defeat by destroying Miletus, but the city was soon afterward rebuilt and by the middle of the fifth century b.c. it was once again a flourishing port and commercial center.
The far-ranging maritime activities of the Milesians brought them into contact with older and more advanced civilizations in the Middle East, particularly in Egypt, from which the Greeks returned with ideas as well as goods. Herodotus writes that “the Egyptians by their study of astronomy discovered the solar year and were the first to divide it into twelve parts—and in my opinion their method of calculation is better than the Greek.”
The trade routes of the Milesians also took them to Mesopotamia, where they probably acquired the knowledge of astronomy they needed for celestial navigation and timekeeping. They obtained the gnomon, or shadow marker, in Mesopotamia, according to Herodotus, who says that “knowledge of the sundial and the gnomon and the twelve divisions of the day came into Greece from Babylon.” The gnomon was also used to determine the equinoxes, when the sun rises due east and sets due west, as well as the winter and summer solstices, when the noon shadow is longest and shortest, respectively.
The Greek word for star, aster, is derived from Ishtar, the Babylonian fertility goddess, whom the Greeks identified with the planet Venus. They at first thought that Venus was two different stars, calling it Eosphoros when it was seen before sunrise and Hesperos when it appeared in the evening. They later realized that the morning and evening stars were the same celestial body, which they called Aphrodite, the goddess of love, thus perpetuating the cult of Babylonian Ishtar. Venus is the only planet mentioned by Homer, who in the Iliad calls it Eosphorus when describing the funeral of Patroklos, and Hesperos when telling of the battle between Achilles and Hektor. Sappho also sings of Venus alone among the planets, and then only as Hesperos, “fairest of all the stars that shine.”
The Ionian Greeks soon progressed far beyond their predecessors intellectually, particularly in Miletus, which in the last quarter of the sixth century B.C. gave birth to the first three philosophers of nature. All that is known of their thought are fragmentary quotes or paraphrases of their works by later writers. Aristotle referred to them as physikoi, or physicists, from the Greek physis, meaning “nature” in its widest sense, contrasting them with the earlier theologoi, or theologians, for they were the first who tried to explain phenomena on natural rather than supernatural grounds. Earthquakes, for example, which both Homer and Hesiod attributed to the action of Poseidon, the “earth shaker,” were explained by Thales as the rocking of the earth while it floated in the all-encompassing waters of Oceanus.
Plato listed Thales (ca. 625–ca. 547 B.C.) among the Seven Sages of ancient Greece, while Aristotle considered him to be the “first founder” of Ionian natural philosophy. There is a tradition that Thales visited Egypt, where he is supposed to have calculated the height of a pyramid by pacing off its shadow, doing this at the time of day when the height of any object is equal to the length of its shadow. Herodotus credits Thales with having predicted the total eclipse of the sun visible in central Asia Minor on 28 May 585 B.C., when the Lydians and Persians were at war. Given the state of knowledge at the time, it would have been impossible for Thales to predict that an eclipse might be visible in that region, but once he became enshrined as one of the Seven Sages all sorts of intellectual accomplishments were attributed to him, including the first geometrical theorems known to the Greeks.
The most enduring ideas of the Milesian physicists proved to be their speculations on the nature of matter, particularly their belief that there was an arche, or fundamental substance, that endured through all apparent change. Aristotle writes that “Thales, who led the way in this kind of philosophy, says that the principle is water, and for this reason declared that the earth rests on water.” Aristotle thought that Thales chose water as the arche “from the observation that the nourishment of all creatures is moist...and water is for most moist things the origin of their nature.” His choice of water was undoubtedly because it is normally a liquid but when heated becomes a vapor and when frozen is transformed to solid ice, so that the same substance appears in all three forms of matter. More fundamentally, Thales was trying to answer a question that marks the beginning of Greek philosophy: What is the nature of the reality behind phenomena?
Anaximander (ca. 610–ca. 545 B.C.) was a younger friend of Thales’s and a fellow citizen of Miletus. Following the tradition that Thales left no writings, Themistius (ca. 317–ca. 388) describes Anaximander as “the first of the Greeks, to our knowledge, who was bold enough to publish a treatise on nature.” Ancient sources also attribute to Anaximander books on astronomy, where he is said to have used the gnomon to determine “solstices, times, seasons and equinoxes,” as well as a work on geography in which he was the first to draw a map of the ecumenos, the inhabited world.
Anaximander called the fundamental substance apeiron, the “boundless”; the term is sometimes translated as “the infinite,” meaning that it is not defined—that is, limited by having specific properties. He realized that water could not be the arche, for it already possessed form and definite qualities, whereas the fundamental substance must be absolutely undifferentiated in its original state.
According to Anaximander, there are at any given time innumerable worlds that have been “separated off” from the infinite. This notion derives from an ancient Greek belief that in the beginning heaven and earth had a single form, and that they later separated to assume an infinite variety of appearances. Euripides refers to this legend in his play Melanippe the Wise where Melanippe says, “The tale is not mine, I had it from my mother, how heaven and earth were one form; and when they were parted from one another, they gave birth to all things, and gave forth to the light [such things as] trees, flying things, beasts, the nurslings of the salt sea, and the race of mortals.”
Anaximander thought that the earth, which he believed to be cylindrical in form, was at the center of the universe, where it “hangs freely, not by the compulsion of any force but remaining where it is owing to its equal distance from everything.” He is saying that the earth remains fixed at the center because there is no reason for it to move in one direction or another, an idea known as the principle of the “lack of a sufficient reason.” The use of this principle by Anaximander marks the boundary between mythology and science, which always requires an explanation in terms of a sufficient cause.
Anaximander also wrote on the origin of animal and human life, and Plutarch credits him with believing in a theory of evolution: “He says moreover that originally man was born from creatures of a different species, on the grounds that whereas other creatures quickly find food for themselves, man alone needs a long period of suckling; hence if he had been originally what he is now he could never have survived.”
Anaximenes (fl. 546 B.C.) was a younger contemporary of Anaximander’s, who is described as his friend and mentor. Anaximenes believed that the only conceivable explanation for the nature of physical reality was that “all things proceed from one and are resolved into the same.” He held that the prime substance is pneuma, meaning “breath” or “air”; pneuma assumes various forms through its eternal motion. Anaximenes not only identified the arche, but also described the natural phenomena by which it takes on one form or another, another step forward in the development of science. According to Simplicius, writing in the sixth century A.D., Anaximenes says that the pneuma “differs in rarity and density according to the different substances. Rarefied it becomes fire; condensed it becomes first wind, then cloud, and when condensed still further water, then earth and stones. Everything else is made of these.” Simplicius notes that Anaximenes also postulated “eternal motion, which is indeed the cause of the change.”
Anaximenes thought that the earth was flat and floated upon the air “like a leaf,” as did the celestial bodies. He believed that the earth and the heavenly bodies were surrounded by boundless air, which contained an infinite number of other worlds. One fragment quoted from his work gives an analogy between an individual human being and the cosmos. “As our soul,” he says, “which is air, holds us together, so do breath and air encompass the whole world.”
A quite different view of nature was taken by Heraclitus (fl. ca. 500 B.C.), a younger contemporary of Anaximenes’ who was born in the Ionian city of Ephesus, north of Miletus.
Heraclitus was known as Skoteinos, meaning “Dark” or “Obscure,” because of the enigmatic quality of his oracular statements. One of his fragments says that “The Lord [Apollo] whose oracle is at Delphi neither speaks nor conceals, but gives a sign.” His contemporaries also called him the paradoxolog—a maker of paradoxes—because of his love of paradox and puzzle. Diogenes Laertius, in his Lives of Eminent Philosophers, written ca. a.d. 325, says that Heraclitus collected his gnomic sayings in a book that he deposited in the temple of Artemis at Ephesus. A probably apocryphal story has it that when Socrates was asked by Euripides what he thought of this book, he replied, “What I understood was fine, and no doubt also what I didn’t understand; but it needs a diver to get to the bottom of it.”
Heraclitus believed that the enduring reality in nature is not Being, as in the existence of a universal substance, but Becoming, that is to say, perpetual change, hence his famous aphorism “Panta rhei” (Everything is in flux). Whereas the Milesian physicists looked for a basic substance that remained unchanged in natural phenomena, Heraclitus focused on change itself and the ceaseless flux of nature, as in the famous fragment mentioned by Plato: “Heraclitus somewhere says that all things are in process and that nothing stays still, and likening existing things to the stream of a river he says you would not step twice into the same river.”
The relative stability of nature was the result of what Heraclitus called the opposite tension, a balance of opposing forces producing equilibrium, and the unity of the cosmos was due to Logos, or Reason, which gives order to the natural world. He held that divinity was the unity of opposites, as in his statement that “God is day night, winter summer, war peace, satiety hunger, he undergoes alteration in the way that a fire, when it is mixed with spices, is named according to the scent of each of them.”
Heraclitus believed that the evidence of the senses is deceptive and must be used with caution, since it deals with transitory phenomena, as he says in one of his aphorisms: “Evil witnesses are eyes and ears for men, if they have souls that do not understand their language.”
As science developed, physikoi extended one branch or another of what had already been begun. Hecataeus of Miletus (fl. ca. 500 B.C.), a contemporary of Heraclitus’s, is credited with following the lead of Anaximander in drawing a map of the world known to the Greeks. As a supplement to his map he also wrote a work entitled Periegesis, a “guide” or “journey round the world,” a description of the countries and people to be seen on a coastal voyage around the Mediterranean and the Black Sea, along with some excursions inland, ranging as far as Scythia, Persia, and India. The enormous extent of his map is a measure of how far abroad the Greeks had traveled in their colonization and trade, exposing them to cultures around the Mediterranean and the Black Sea.
From the Hardcover edition.