The Cave and the Light Read online

  The Platonic solids described in the Timaeus were God’s building blocks of the cosmos.

  Still, did Plato really mean for the Timaeus, with all its fantastic imagery, totally unprovable but dogmatically persuasive, to be taken at face value? His most famous pupil, Aristotle, certainly thought so. Unlike some modern scholars who insist Plato never meant the Timaeus literally, Aristotle also had the advantage of hearing Plato’s own lectures on the subject. But it really doesn’t matter. Over the centuries Plato’s followers, and to a large extent Greek as well as Latin Christendom, would accept the Timaeus as the authoritative account of the creation of the cosmos and a precious insight into the workings of the mind of God.24

  This is a cosmology in which the same Platonic dualities keep recurring, in chapter after chapter of the Timaeus. There is the division between the Same and the Other, and between the Limit and the Unlimited drawn from Pythagorean sources. There is also the division between Divine Mind and physical matter that appears in other Platonic dialogues but which the Timaeus raises to new cosmic significance.

  It is a universe that we perceive as multiform and constantly changing, but which is, in the clear light of reason, actually eternal and One.25

  And presiding over this complete and ordered cosmos is a God unlike any that has appeared in Greek thought, or indeed anywhere in history. It is a God who is a rational, beneficent Creator, who is pure spirit and pure mind. He is a Creator who occupies no existence in space yet presides over all things that occur in space and time. He is a God who demands from us not worship through ritual and sacrifice, but our mind’s assent to the laws and principles He has laid out for His creation.26

  The influence of Plato’s image of God as a rational Creator knowable through our reason would be immense, and not only in ancient Greek thought. It would shape the whole notion of God in early Christianity. In fact, the word Plato uses for his ordered creation, genesis, will become the title of the first book of the Greek translation of the Hebrew Bible. In time, early Christian and medieval commentators will carefully stitch together Plato’s version of creation and Moses’s into a harmonious whole, so that spiritual-theological and rational-scientific elements of both the Old Testament and the Timaeus could emerge as one coherent system we still call Intelligent Design.

  In addition, the Timaeus’s insistence that physical matter is simply inert material waiting for the imprint of nous, or reason, in order to have any significance or motion became a central theme of ancient and medieval science. Even Plato’s rival Aristotle will make it a starting point for his own work.27 Likewise, the idea of planetary motion as a harmonious system of circles or spheres (later called “the music of the spheres”), and of man as a microcosm of the universe with a body, mind, and soul in tune with the larger harmonies of creation, marks the start of long, influential chapters in Western thought.

  The sacred geometry of the Timaeus would reach across the Middle Ages to the Renaissance. It leaves its mystic imprint on the philosopher Nicholas of Cusa (one of whose disciples will be a Polish astronomer named Nicolaus Copernicus), on Leonardo da Vinci, and even on the Sistine Chapel ceiling. It is not for nothing that Raphael has Plato offer the Timaeus as his most representative work in The School of Athens or that Pythagoras himself appears in the painting sketching a diagram of the tetraktys, which Pythagoras proposed, and Plato accepted, as the symbol of the created eternal realm. Still later, Plato’s often expressed view that “God is always doing geometry” and “Where there is number there is order; where there is no number there is nothing but confusion, formlessness, and disorder” would decisively shape the scientific views of Copernicus, Kepler, and Galileo, not to mention Isaac Newton and Albert Einstein.b28

  Long before that, however, the Timaeus occupied pride of place in the school Plato founded in Athens to carry on his ideas. We don’t know exactly when Plato decided he needed a formal school to pass on his ideas or acquired a parcel of land a mile outside the walls of Athens near a grove sacred to an Athenian hero, Academus, as the place to build it. It was probably just before or just after his first trip to Italy in 388–86, when he was nearly forty. When he returned, he devoted himself to organizing an entire course of study for his growing number of students, and eventually the Timaeus joined a batch of other lengthy later dialogues—the Laws, Philebus, and Statesman—as a central textbook for Plato’s disciples.

  It is important to see these not as replacing the earlier works, like the Republic or the Phaedo, which students almost certainly continued to read. Instead, the new works highlighted features of the old and gave them a new significance as Plato’s fascination with number as the architecture of reality seemed to explain what had, like the Forms, been puzzles before.

  In the Philebus, for example, Plato applies his mathematical theories to ethics. He shows, or tries to show, that virtue itself is a matter of harmonious proportion, not unlike the intervals of the musical scale: that all human activities involve finding the right measure between the Unlimited and Indeterminate and the stabilizing Limit, and that the good life depends on the permanent establishment of right and definite measure or proportion.29 In effect, the Forms, even the Good in Itself, turn out to be nothing more than mathematical formulae for virtuous living—even if the actual calculations remain vague and elusive.

  Still, the fact that studies at the Academy involved no less than ten years of mathematics, and that the motto over the door read, “Let no one ignorant of Geometry enter here,” suggests just how powerful that Pythagorean impulse remained in Plato’s program. It may explain why Plato taught his students that numbers cannot be added together. If we are talking about numbers as arithmetical figures, the statement is obvious nonsense. But if we are talking about number as an abstract Form representing a class of objects (a notion very close to modern mathematics), then it takes on a more profound meaning.30 No wonder the leading mathematician of the age, Eudoxus of Cnidus, moved his entire school to Athens to make common cause with the Academy—an intellectual collaboration that laid the foundation for Euclidean geometry.31

  Meanwhile Plato’s Academy would become the model for every monastery and university on the Western model. Students lived in small huts scattered around the property and shared common meals in Plato’s house, while Plato himself seems to have regularly held classes in the garden or in the park.32 Plato’s school became the Greek world’s principal training ground for two types of graduates: mathematicians and geometers, and public policy legislators who knew how to turn the principles of sacred geometry into the principles of the perfect State.

  The juxtaposition seems startling, yet in Plato’s ordered world, perfection in one should be reflected in the other. And others seemed to have agreed with him. For example, Plato’s student Phormion went to Elis to straighten out its laws and institutions; Aristonymus to Megalopolis; and others to other city-states. The Cyrenaeans asked Plato to come to them in person, but he refused. However, when Perdiccas, king of Macedonia, asked him for a trained counselor, Plato dispatched another Academy student, one of his cleverest, named Euphraeus.

  Euphraeus exhorted the members of the Macedonian court “to study geometry and philosophy.”33 What Macedonia’s aristocracy, who devoted themselves to drinking when they weren’t breeding horses or fighting, thought about this advice isn’t recorded. However, Euphraeus did convince King Perdiccas to give his royal heir a special province to rule so he could learn the skills of kingship. The experiment worked better than anyone could have imagined. Perdiccas’s heir, Prince Philip, would become Macedonia’s greatest king and within two decades conqueror of Greece. In fact, Philip’s entire meteoric career—later overshadowed by the fame of his own son Alexander and his tutor Aristotle—owed its start to Euphraeus and indirectly to Plato.

  This intermingling of philosophy and high policy is in keeping with the spirit of Plato’s Academy. Anyone imagining that the philosopher’s life would be one of serene contemplation of the Forms would be amazed by Plato�
��s later years at the Academy.

  It was a bustling place. Students flocked from every part of Greece, as Plato presided as moderator over seminar-style discussions of the most important dialogues. The rest of his time was spent lecturing. These lectures were open to the general public, and people turned up in droves to hear Plato on topics like “The Nature of the Good.” Plato grew so busy that for nearly twenty years he did not write a word except the Philebus. When he finally pulled himself away from his hectic routine, he managed to sit and write the Sophist, Timaeus, Statesman, and the other late dialogues. Not bad for a man approaching eighty.

  Yet even at the end Plato never put himself in his own work. Nor would he acknowledge himself as author. “There never is and never shall be any treatise by Plato,” he wrote in a revealing passage in one of his letters, “what now bears the name belongs to Socrates beautified and rejuvenated.” Until the end of his life, everything he wrote or did, including founding the Academy, was a tribute to his dead friend and teacher: the greatest monument of any disciple ever left to his master.

  After Plato’s death in 347, the Academy continued to flourish. Under his successors, it drew the best and the brightest students for nine hundred years, until it formally closed its doors in 529 CE.

  But the most famous Academy student of all was the one who rejected it all.

  * * *

  * For more on Plato’s politics, see chapter 5.

  † Much of it, apparently, derived from the view of the underworld conveyed by the Orphic mystery cult.

  ‡ For more on Atlantis, see chapter 4.

  § According to Herodotus, he was born in Samos and fled to the city-state of Croton in southern Italy to escape the tyranny of his home island’s ruler. In Croton, Pythagoras is said to have risen to a position of considerable authority, but eventually he was overthrown and left for Metapontium, where he died.

  ‖ Pythagoras’s belief that reality was essentially dual, split between the Limit (one) and the Unlimited (two), and that the soul was immortal and transmigrated after death, also surfaces in Socrates’s view of the world as reflected in the dialogues.

  a This is when the ratio between the two parts of a divided line are equal to the ratio of the longer section to the entire line. When used to turn a square into a rectangle, as the Greeks often did (for example, in designing the Parthenon), the result was said to be so visually pleasing it had to be of divine origin.

  b Einstein never lost sight of this idea of a cosmos as a totality and devoted his last years to finding the common mathematical pattern that would (for example) tie together gravitation and the forces of electromagnetism. It made him resentful of the suggestion of the randomness of nature embedded in quantum theory and made him keep reminding his fellow physicists, “God is not malicious,” and, “God does not play dice.” Finally, Niels Bohr (who was something of a Platonist himself) retorted, “Stop telling God what to do.”

  Aristotle (384–22 BCE)

  Four

  THE DOCTOR’S SON

  All men by nature desire to know. An indication of this is the delight we take in our senses.

  —Aristotle, Metaphysics

  The Academy’s most famous dropout was raised in Macedonia, the Texas of ancient Greece. A wild, rugged country of hardy horsemen and splendid warriors, Macedonia came into its own in the fourth century BCE as city-states like Athens and Sparta went into decline. Macedonia’s king Philip (the same Philip who had been the pupil of Plato’s student Euphraeus) would unite all of Greece under his rule. His son Alexander, known to posterity as Alexander the Great, would become the ancient world’s greatest conqueror.

  Aristotle’s life and career revolved around the kingdom’s royal house, in more ways than one. Aristotle’s own father, Nicomachus, was the Macedonian royal physician. The son would go on to become Alexander’s tutor. A few years later, that extraordinary figure would launch a career of conquest that eventually extended from Greece and Egypt to Afghanistan and the Punjab.

  Evidence suggests that teacher and pupil were closer than some—remembering Alexander’s ruthless, bloodthirsty career—would like to think. All the same, it is Aristotle’s relationship with Plato, not Alexander, that defined and determined the course of his career. Although he absorbed many of its elements and assumptions, Aristotle turned foursquare against the elaborate system of philosophy his mentor had carefully crafted. That act of rebellion explains the key features of Aristotle’s own thought and defines his place in the making of Western civilization.

  Legend says Aristotle, like Socrates, was short but strongly built. It also says he spoke with a lisp.1 The most authentic portraits reveal a man with a broad brow and a firm jaw, with intense, watchful eyes. It’s a face that doesn’t tolerate nonsense or prevarication. It is the face of robust common sense.

  Aristotle is no woolly-minded, dreamy-eyed philosopher. He is the realist and empiricist compared with Plato the mystic and idealist. Aristotle believed his teacher’s dismissal of the material world as a realm of illusion and error was a major mistake, and he devoted himself to analyzing that world in all its rich multiplicity. If Plato tells us to leave the cave in order to find a higher truth beyond the senses, Aristotle retorts: Don’t be in such a hurry. What happens in that cave is not only important, but the only reality we can truly know.

  They began as student and master. They ended as rivals. Plato is supposed to have said, “Aristotle kicked me, as foals do their mothers when they are born.”2 All the evidence, however, suggests the crucial break between them came after Plato’s death. Aristotle entered Plato’s Academy in Athens at age seventeen, probably in 367 BCE. When he left, he was in his forties. Plato was the formative influence in Aristotle’s life, just as Socrates was in Plato’s. In fact, Aristotle wrote his earliest works (now lost) in the same dialogue form.

  Exactly when Aristotle broke with his mentor is less important than why and even where it happened, and what fault lines it left behind. Most accounts agree he left Athens after Plato died in around 347 BCE and moved to Atarnaeus, a small town in Asia Minor directly opposite the island of Lesbos. Why did he leave? Philip of Macedon had just crushed the armies of the Greek city-states at the battle of Olynthus. It may not have been a good time for a Macedonian to hang around Athens. Aristotle may also have been disappointed that he, Plato’s most brilliant pupil, was passed over as the great man’s successor and that leadership of the Academy went to Plato’s nephew Speusippus—an example of the nepotism rife in ancient Greece, even at the philosophical level.*

  In any case, Aristotle made a new life for himself in Atarneus, and later on Lesbos. He married the niece of the local ruler, Hermias. He taught classes and met a student, Theophrastus, who would carry on Aristotle’s life’s work after his death. In his spare time, he walked the white sandy beaches and climbed the hills around the town and the island. He observed the rich variety of fish and mollusks found in tidal pools and the clear open waters, and the birds and small animals and tiny insects that wandered through its groves. The experience gave him a lifelong fascination with nature and a passion for analyzing and understanding its seemingly bewildering teeming life. It was on Lesbos that Aristotle probably made his first attempts to dissect biological specimens.

  These experiences coincided with, and reinforced, the doubts he had already had about Plato’s successor at the Academy, Speusippus, and eventually about Plato himself. Speusippus had largely given up on Plato’s theory of Forms and the mystical theory of ideal numbers outlined in the Timaeus.3 But Plato’s nephew still clung to the notion that the truth about reality had to be found in mathematical formulae. However, Aristotle saw at once that even if the proposition that math is a certain and exact science is true, and even if the proposition that the first principles in philosophy must be certain and exact is also true, that did not prove that those first principles must be mathematical. The Pythagorean belief that “all things are numbers” was one of the first assumptions Aristotle’s own work wou
ld overturn.4 Aristotle had even less patience with the lingering Pythagorean emphasis on secrecy and cryptic aphorisms, which flew in the face of Aristotle’s overriding conviction that philosophy must necessarily be an open book, with everything as clear, organized, and straightforward as possible even for the slowest student.

  That same insistence would ultimately make him impatient with Plato’s reliance on allegory and myth to convey truths he considered too profound to be expressed in ordinary language. The Myth of the Cave in the Republic, the Myth of Atlantis in the Timaeus: Aristotle made it clear he had no time for tall tales like these, which obfuscate more than they reveal. “Plato raised up the walls of Atlantis,” Aristotle wrote, “and then plunged them under the waves,” meaning that the whole story was an obvious fabrication and nothing more. “About those who have invented clever mythologies,” he added in the Metaphysics, “it is not worthwhile to take a serious look.”5

  In the end, he also rejected the most powerful myth Plato ever created: the myth of Socrates himself.6 Socrates does appear in Aristotle’s writings, but he is not a heroic figure or a philosophical role model. He is simply one more object of analysis and criticism like all Aristotle’s other predecessors, including Plato. Everyone and everything were becoming bricks in the comprehensive and complex edifice Aristotle was determined to build in order to reach the most profound truths. Those truths, as he made clear,† come not in a sudden moment of intuitive insight or from some inner contemplative process. They are the result of hard work and thought. Of course it would be nice, Aristotle tells us, to be as certain about everything as we can be about mathematical truths. It would be lovely to know the answer almost the instant we ask the question, as when we say 2 + 2 = 4: in other words, to know truth a priori. All of Aristotle’s works point out, however, that the most vital knowledge we have comes a posteriori, meaning “after the fact” or from experience, as we link up a given visible effect to its preceding cause.