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 650B.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.
The use of a gnomon in determining the seasons. The examples here are from the middle northern latitudes. The upper drawing shows the seasonal variations of the sun's path and the shadows that it casts at noon and sunset; the term “equinoctial” (equal day and night) refers to both the vernal (spring) and autumnal (fall) equinoxes. The lower drawings show the gnomon's shadows at the solstices and equinoxes. (from Kuhn, 1957)
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 585B.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 apurón, 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 Anaximan-der'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.
During the third quarter of the sixth century B.C. the Ionian intellectual enlightenment spread to Magna Graecia, sparked by two of the most original minds of the archaic period, Pythagoras and Xenophanes.
Pythagoras (ca. 560-ca. 480 B.C.) was born on Samos, one of the two Aegean islands that were part of the Panionic League, lying off the Aegean coast of Asia Minor northwest of Miletus. There is a late tradition that in his youth Pythagoras traveled to both Egypt and Babylonia to study mathematics. When Pythagoras came of age he fled from the rule of Polycrates, the tyrant of Samos, and moved to Croton in southern Italy, a Greek colony founded in the eighth century B.C. There he established a society that was both a scientific school and a religious sect; its beliefs included that of metempsychosis, or the transmigration of souls. Otherwise little is known of Pythagoras himself, and it is impossible to distinguish his own ideas from those of his followers.
The Pythagoreans are credited with laying the foundations of Greek mathematics, particularly geometry and the theory of numbers. The most famous of their discoveries is the Pythagorean theorem, which says that in a right triangle the square of the hypotenuse equals the sum of the squares of the other two sides.
Their religious beliefs also led the Pythagoreans into numerology, or number mysticism, including such notions that odd numbers have male characteristics and even ones female. The most sacred number is ten, the sum of the first four numbers, where one is the “atom” of numbers, of which two generate a line, three if not all in a line determine a plane, and four if not all in the same plane form the vertices of a solid. Arrayed one above another as a series of dots, or “figurative numbers”—that is, 1(.), 2(…), 3(…), 4(….)—the first four integers form an equilateral figure known as the tetractys, the number of the universe, since it is the sum of all possible dimensions. The tetractys became the symbol of the Pythagoreans, who in time acquired the reputation of being magicians and sorcerers. The third-century church father Hippolytus writes in his Phibsophumena of “magical arts and Pythagorean numbers” and notes that “Pythagoras also touched on magic, as they say, and himself discovered an art of physiognomy, laying down as a basis certain numbers and measures.”
Another idea attributed to the Pythagoreans is the concept of “cosmos”—kosmos in Greek—which a modern dictionary defines as an “orderly, harmonious and systematic universe.” The original Greek meaning of kosmos is given by Plato in a passage fromMeno,where he appears to be referring to the Pythagoreans. “The wise men,” he says, “tell us that heaven and earth, gods and men are bound together by kinship and love and orderliness and temperance and justice; and for this reason, my friend, they give to the whole the name of kosmos, not a name implying disorder or licentiousness.”
According to tradition, the Pythagoreans were the first to recognize the numerical relations involved in musical harmony, to which they were led by their experiments with stringed instruments. This made them believe that the cosmos was designed by a divine intelligence according to harmonious principles, and that this harmony could be expressed in terms of numbers. As Aristotle wrote of the Pythagoreans: “They supposed the elements of numbers to be the elements of all things, and the whole heaven to be a musical scale and a number.”
Philolaus of Crotona, who flourished in the second half of the fifth century B.C., is supposed to have written a comprehensive work on Pythagorean cosmology. According to Philolaus, the Pythagoreans believed that the earth was not stationary but moved in a circle around a central fire called Hestia, the hearth of the cosmos, along with the sun, the moon, the stars, and the five visible planets—Mercury, Venus, Mars, Jupiter, and Saturn—as well as another body known as the “counter-earth,” invisible because it was on the opposite side of the cosmos. They thought that the celestial bodies moved in such a way as to create a celestial harmony, as Alexander of Aphrodisias writes in his commentary on Aristotle's Metaphysics: “They said that the bodies which revolve around the center have their distances in proportion, and some revolve more quickly, others more slowly, the sounds which they make being deep in the case of the slower, and high in the case of the quicker; these sounds then, depending on the ratio of the distances, are such that their combined effect is harmonious.”
Aristotle writes of how the Pythagoreans explained why we do not hear this celestial harmony: “They account for it by saying that the sound is with us right from birth and has thus no contrasting silence to show it up; for voice and silence are perceived by contrast with one another, and so all mankind is undergoing an experience like that of a coppersmith, who becomes by long habit indifferent to the din around him.” Thus ordinary mortals are not aware of the divine harmony, as Lorenzo explains to Jessica in The Merchant of Venice.
There's not the smallest orb which thou behold'st
But in his motion like an angel sings.
Still quiring to the young-eyed cherubims;
Such harmony is in immortal souls,
But, whilst this muddy vesture of decay
Doth grossly close it in, we cannot hear it.
The poet and philosopher Xenophanes (ca. 570-after 478 B.C.), a somewhat older contemporary of Pythagoras's, was born in the Ionian city of Colophon, northwest of Ephesus, and is said to have been a disciple of Anaximander's. He fled from Ionia after it was conquered by the Persians in 545 B.C. and moved to Magna Graecia, where, according to Diogenes Laertius, he lived in Sicily at Zancle and Catana, two Greek colonies founded in the eighth century B.C. He became the poet of the Ionian enlightenment in the West, and though his extant fragments are primarily of literary rather than scientific interest, some of his seminal ideas profoundly influenced the development of natural philosophy in Magna Graecia.
Xenophanes objected to the anthropomorphic polytheism of Homer and Hesiod, whom he condemned for having “ascribed to the gods all deeds that among men are a shame and a reproach: thieving, adultery and mutual deception.” He said that men make gods in the image of themselves, so that “the Ethiopians say their gods are snub-nosed and black, the Thracians that theirs have light blue eyes and red hair.”
His own view was both monotheistic and pantheistic, as is evident from one of his fragments: “God is one, greatest among gods and men, in no way like mortals either in body or mind. He sees as a whole, perceives as a whole, hears as a whole. Always he remains in the same place, not moving at all, nor does it befit him to go here and there at different times; but without toil he makes all things shiver by the impulse of his mind.”
The Pythagorean notion of the transmigration of souls was ridiculed by Xenophanes, who in one of his poems tells the story of how Pythagoras stopped a man beating a dog, saying to him “Stop, do not beat him. It is the soul of a friend, I recognize his voice!”
Tradition has it that Xenophanes was the teacher of Parmenides (ca. 515-ca. 450 B.C.) of Elea, a colony founded on the Tyrrhenian coast of Italy by the Ionian city of Phocaea. Like Heraclitus, Parmenides stressed the unreliability of the senses, saying that one should not “let custom, born of much experience, force thee to let wander along this road thy aimless eye, thy echoing ear or thy tongue, but do thou judge by reason the strife-encountered proof that I have spoken.”
Whereas Heraclitus believed that everything was in a state of flux and nothing was permanent, Parmenides denied absolutely the possibility of motion and any other kind of change, holding that they were mere illusions of the senses. As he wrote in his didactic poem The Way of Truth, “Either a thing is or it is not,” meaning that creation or destruction or any other kind of change was impossible, including motion.
Parmenides did not admit the existence of multiplicity and time; all that exists, he said, is one and now. His cosmos is a full, uncreated, indestructible, changeless, motionless, eternal, and perfect sphere of being, and all sensory evidence to the contrary is illusion. Echoes of this immutable Parmenidean cosmology reverberated from antiquity down to the European Renaissance, as in the last canto of Spenser's The Faerie Queene:
Then gin I thinke on that which Nature sayd,
Of that same time when no more Change shall be,
But stedfast rest of all things, firmely stayd
Upon the pillours of Eternity,
That is contrayr to Mutabilitie;
For all that moveth doth in Change delight
The philosophy of Parmenides was vigorously defended by his pupil Zeno of Elea (ca. 490-ca. 425 B.C.), who proposed several paradoxes designed to show that apparent motion is illusory. One of these concerns a hypothetical race between Achilles and a tortoise, which is given a head start to make up for its slowness. Achilles runs to catch up, but to do so he must first reach the point from which the tortoise started, by which time it will have moved farther, and likewise in each diminishing interval that follows. The number of such intervals is infinite, according to Zeno, and although the times become increasingly shorter their sum is limitless. Thus Achilles will never catch the tortoise, and the conclusion is that motion is an illusion of the senses. This and the other paradoxes of Zeno were not fully resolved until the second half of the nineteenth century, when mathematicians proved that the sum of an infinite series, such as that involved in the race between Achilles and the tortoise, can be finite.
Some of the profound questions raised by Parmenides were ad dressed by Empedocles (ca. 482-ca. 432 B.C.) of Acragas, another Greek colony in Sicily. Empedocles was the author of two hexameter poems, one entitled On Nature and the other Purifications, of which a total of 450 lines have survived in the form of quotations by Aristotle and other later writers. While Empedocles agreed with Parmenides that there was a serious problem regarding the reliability of sense impressions, he insisted that we are utterly dependent on our senses, for they are our only direct contact with the world of nature. He warned, however, that we must carefully evaluate the information obtained by our senses to gain true knowledge. “But come, consider with all thy powers how each thing is manifest, neither holding sight in greater trust as compared with hearing, nor loud-sounding hearing above the clear evidence of thy tongue, nor withhold thy trust from any of the other limbs [organs], wheresoever there is a path for understanding, but think on each thing in the way in which it is manifest.”
According to Aristotle, Empedocles was the first to say that there were four fundamental substances—earth, air, fire, and water—which he called the “roots of everything.” Referring to the four elements, he said that “from these things sprang all things that were and are and shall be, trees and men and women, beasts and birds and water-bred fishes, and the long-lived gods too, most mighty in their prerogatives.” He has the four substances intermingling and separating under the influence of two forces that he calls Love and Strife. He says “the elements are continually subject to an alternate change, at one time mixed together by Love, at another separated by Strife.”
Empedocles thus introduced the concept of force as distinct from matter as the physical cause for the phenomena in nature. He pictured the cosmos as existing in a state of dynamic equilibrium between the opposing forces, with motion taking place when either predominates. His identification of earth, water, and air as elements corresponds to the modern classification of matter into solid, liquid, and gaseous states. Fire to him represented not only flames but phenomena occurring in the heavens, such as lightning and comets. The Empedoclean theory of the four elements was one of the most enduring in the history of science, lasting for more than two thousand years. It left its impress on literature as well as science, as evidenced by the lines in The Faerie Queene, where Spenser writes of how the four elements “the groundwork bee / Of all the world and of living wights.” He continues:
To thousand sorts of Change we subject see:
Yet are they chang'd (by other wondrous slights) Into themselves, and lose their native mights;
The Fire to Ayre, and th’ Ayre to Water sheere,
And Water into Earth; yet Water fights
With Fire, and Ayre with Earth, approaching neere:
Yet all are in one body, and as one appeare.
Empedocles had several other original ideas. He held that light travels through space with great but finite speed. He was also the first to show that air, although invisible, is a real physical substance. He demonstrated this by taking a vessel called a clepsydra, or water clock, and immersing it upside down, showing that no liquid entered until the air was allowed to escape from inside the vessel in equal quantity.
Some of the statements made by Empedocles gave rise to legends that he was a divine healer and a wonder worker. “I, an immortal god,” he says in one of his fragments, “no longer a mortal, go about among you all, honored as is fitting, crowned with fillets and flowery garlands.” He goes on to describe how his disciples crowded about him, “asking the path to gain, some desiring oracles, while others seek to hear the word of healing for all kinds of diseases.” One of the stories told about Emped ocles was that he left the world by jumping into the volcanic crater of Mount Etna, leaving only his sandals behind, though other legends have him ending his days as an exile in the Peloponnesos.
A radically different theory of matter from those of Empedocles and Parmenides was later proposed by Leucippus, who was probably born in Miletus late in the sixth century B.C. and moved to Abdera in Thrace, which had been founded circa 500 B.C. by refugees from the Ionian city of Teos. His lost work The Greater World System apparently originated the atomic theory, which is usually credited to his pupil Democritus.
Democritus (ca. 470-ca. 404 B.C.) was born at Abdera and is reported to have visited Athens, but no one knew him there, according to the Greek biographer Diogenes Laertius. His version of the atomic theory appeared in a book entitled the Little World System,which he may have so called out of deference to the work of his teacher Leucippus.
The atomic theory of Leucippus and Democritus holds that the arche exists in the form of atoms, the irreducible minima of all physical substances, which through their ceaseless motion and mutual collisions take on all of the various forms observed in nature. The only extant fragment by Leucippus himself says, “Nothing occurs at random, but everything for a reason and by necessity.” By this he meant that atomic motion is not chaotic but obeys the immutable laws of nature.
According to Democritus, there is no limit either to the number of atoms or the extent of the void, and so innumerable worlds are possible, of which our cosmos is only one. One of his surviving fragments quotes Democritus as saying that
there are innumerable worlds of different sizes. In some there is neither sun nor moon, in others they are larger than in ours and others have more than one. These worlds are at irregular distances, more in one direction and less in another, and some are flourishing, others declining. Here they come into being, there they die, and they are destroyed by collision with one another. Some of the worlds have no animal or vegetable life nor any water.
Another Democritian fragment has him saying that he was younger but contemporary with the philosopher Anaxagoras, who was born circa 500 b.c. in the Ionian city of Clazomenae, which he left for Athens at the age of twenty. Anaxagoras was the first philosopher to live in Athens; he resided there for thirty years, becoming a teacher and close friend of Pericles’.
The views of Anaxagoras on the nature of matter were even more pluralistic than those of Empedocles, for he postulated the existence of a very large number of elements in his “seed theory.” “We must suppose,” he writes, “that there are many things of all sorts in things that are aggregated, seeds of all things, with all sorts of shapes and colors and tastes…. There is a portion of everything in everything.” He also postulated an element called the aether, which was in constant rotation and carried with it the celestial bodies. He said that “the sun, the moon and all the stars are red-hot stones which the rotation of the aether carries round with it.” The aether proved to be a very enduring concept, and it reappeared in cosmological theories up until the early twentieth century.
Another of his ideas concerned what the Greeks of his time called Nous, or Mind, by which he meant the directing intelligence of the cosmos, as opposed to inert matter. This earned for Anaxagoras the nickname of Nous, as Plutarch notes in his Life of Pericles:
But the man who most consorted with Pericles… was Anaxagoras the Clazomenian, whom men of those days used to call “Nous“ either because they admired that comprehension of his, which proved of such surpassing greatness in the investigation of nature; or because he was the first to enthrone in the universe not Chance, nor yet Necessity, but Mind (Nous) pure and simple, which distinguishes and sets apart, in the midst of an otherwise chaotic mass, the substances which have like elements.
Around 450 B.C. the enemies of Pericles indicted Anaxagoras on charges of impiety and “medeism”—being pro-Persian. Aided by Pericles, Anaxagoras was able to escape to Lampsacus on the Hellespont, where he founded a school that he directed for the rest of his days. After the death of Anaxagoras, circa 428 B.C., the people of Lampsacus erected a monument to his memory in their agora, the market quarter, dedicating it to mind and truth, which were at the core of his philosophy. The anniversary of his death was for long afterward commemorated in Lampsacus, and by his dying request the students of the city were always let out of school on that day.
Anaxagoras was the last of the Ionian physicists, for even in his own lifetime Athens had replaced Ionia as the common meeting place for philosophers of nature. Xenophanes attributed the decline of Ionia to the corrupting wealth of its citizens, as he writes in one of his poems.
And they learned dainty, useless Lydian ways
While they were still from hated tyrants free.
In robes all scarlet to the assembly went
A thousand men, no less: vainglorious,
Preening themselves on their fair flowing locks,
Dripping with scent of artificial oils.
Such was the world of Ionia, where the first physicists began to speculate about the nature of the cosmos and the bounds of knowledge. Their immediate successors brought philosophy to Magna Graecia and Athens, the first stages in a journey that would take scientific ideas and theories back and forth between East and West like birds on the wing, continuing their flight long after Miletus and the other Ionian cities were reduced to utter ruins.