But the work was frustrating, too. Aristotle would find a pattern or a rule and then he would find an exception to that rule. “Oviparous fish as a rule spawn only once a year,” he noted down with satisfaction, but then a fisherman would bring him a new fish from the lagoon to dissect and he would have to add: “but the little phucis or black goby is an exception, as it spawns twice.”
As he worked, Aristotle became increasingly preoccupied by zoological anomalies. On Lesbos, as the scale of the project grew, the students began to specialize. Theophrastus was studying the plants of the lagoon and the surrounding hills. Aristotle himself was concentrating on the fish. The two men would have exchanged facts and questions across the boundary between their two specialties, just as Darwin and his friend the botanist Joseph Hooker were to do two thousand years later in Darwin’s study. How can an animal be defined? Aristotle would ask his students. What makes an animal absolutely different from a plant? And what makes humans absolutely different from animals? What are the essential differences? And the students repeated back the formula that Aristotle had taught them: humans differ from animals because they have reason; animals differ from plants because they perceive and feel; plants have nutritive and reproductive faculties only. It was a beautifully simple formula.
But in the lagoons of Lesbos and in the sea around its shores, Aristotle found animals and plants that did not fit his definitions. He called them “dualisers” or “borderliners.” The fishermen of Mytilene brought him plant-shaped creatures that appeared to be sensitive to touch and animal-shaped creatures that were rooted to rock—sponges, sea squirts, jellyfish, sea anemones, pinna, and razorshells, each of which had both animal and plant characteristics. The sponges looked like plants—they had branches and roots. They did not move. Yet the fishermen insisted they were sensitive to the touch. They appeared to straddle the two kingdoms. They seemed to suggest that nature moved in a continuous gradation from the nonliving to the living, and from plants to animals.
Instead of turning away from these exceptions to his general theory, Aristotle kept coming back to them. The sea sponges were the most baffling of all the organisms Aristotle studied. Inert, rooted to rock on the seabed, their body shapes resembled a branching tree or sometimes the delicately laced underside of a mushroom. They looked like plants. But under closer examination in a terra-cotta pot full of seawater, Aristotle was certain that he could see excretion going on through the sponge’s pores. And plants do not excrete. When his categories broke down like that, Aristotle knew he was up against something both troubling and important. He was, he wrote in his notes, at a loss. He could see the sea sponge, he could turn it over in his hands, he could dissect it, he could draw and map every tiny orifice of its body, inside and out, he could watch it ingesting plankton under water, but he could not make it out. It did not fit. And his eyes were not strong enough to see even farther inside the sponge’s pores, where there might be more clues to be found.
Sometimes Aristotle was at a loss because he had reached the limit of what he knew or what it was possible to know—he was limited by what his eyes could see; he had no microscope. And sometimes he was at a loss because the thing in front of him—dissected, minutely examined, flayed—just did not fit the patterns he believed to be fundamental to all biological structures. Sometimes both things happened at once. Some sea creatures were simply uncategorizable. When Aristotle was at a loss, the language he used in his notes wavered a little. He did not try to force round pegs into square holes; he was always honest about the difficulties in front of him. He repeated certain words in those moments of unknowing: phainetai, which means “what appears” or “what is evident,” or dokei, which means “what seems” or “what is thought to be the case.” There were sometimes major difficulties in his deciding: “The boundary and the middle, between the non-living and the animals,” he wrote, “escapes our notice [lanthanein]”; “as regards certain things in the sea, one would be at a loss [diaporēseien an tis] to know whether they are animals or plants”; “how to classify them is unclear.”
In his fact collecting on Assos and later on Lesbos, Aristotle relied heavily on the local knowledge of huntsmen, beekeepers, fishermen, sponge divers, and herdsmen as well as on his students. Hermias, no doubt fascinated by Aristotle’s new work, sent him to elderly and experienced men from the mountains or from the coastal villages who could bring him quickly to the bodies of hunted deer before they began to decay or could hunt down certain wild animals for him or bring him a beehive. Aristotle forged relationships with those men by asking endless questions and by respecting their knowledge.
Aristotle could sail out to sea with the sponge divers, but he could not follow them to the seafloor. Sponge diving was skilled and treacherous work. Many of the older sponge divers were deaf because their eardrums had burst. Some were paralyzed, their bodies twisted and contorted from surfacing too fast. They spoke of extraordinary fish and monsters for which they had no name. So, out at sea on the sponge divers’ boats, Aristotle watched the men work.
A single sponge diver took his place at the prow of the boat, with a long rope tied around his waist, a heavy stone in one hand, and a sharp cutting implement in the other, scanning the waves for the familiar shapes of the sponges hundreds of feet below, his mouth full of white oil that he used to light up the darkness of the seabed, his comrades cheering him on. Aristotle would watch the lean body first squat and then arc through the air, disappearing deep into the water, weighed down by the rock, the rope slithering after him into the depths. He would see the diver resurface gasping for air minutes later, clutching a basket full of sponges scythed from the rock on the seafloor. On deck, the resting divers trampled the sponges with their bare feet, rinsing them with seawater and threading them onto a length of rope to be washed again at the back of the boat before the sponges were dried out in the sun and sacked up ready for market.
No one asked the sponge divers questions as Aristotle did. He asked them about touch, about the effect of shadows falling across sponge beds. He needed them, he said, to be absolutely precise in their answers, because he could not go where they went, or see what they saw. Do the sponges sense you coming? Can they hear you? Do they live longer if you cut or pull them off the rock? Do they grow again if you put their severed roots in seawater? And of course, the most pressing question of all: Are they plants or animals? One wonders whether Aristotle shared his philosophical puzzles with the sponge divers and fishermen. And if he had found a way of explaining his project and its philosophical importance, what might those ideas have meant to the sponge divers of Lesbos, who depended in all their dangerous daily work upon rituals and sacrifices, prayers and myths, who leaned on their gods both as protection and as explanation?
The local people had myths to explain everything. They said that the trees in the petrified forest up at Eressos had been turned to stone by Zeus’ thunderbolt; that the enormous bones the farmers sometimes plowed up were the remains of a giant race of humans and animals that had lived long before man and that had been wiped out by jealous gods. Aristotle refused to accept mythical or supernatural explanations for the anomalies he found in the rock pools and nets and caves and under the ground. These were superstitions and folktales, he said. They were not stories for philosophers. He refused to accept any explanation that he could not verify with his own eyes.
But if there were no gods doing the making, one of the sponge divers might have asked Aristotle, how did life come to be? And Aristotle would have told him that there was no beginning, no origin. The world in all its variety has always been and would always be. “Coming to be and passing away,” he wrote, “will … always be continuous and will never fail.” He had come to see the living world as a series of cycles in a serenely perfected and inextinguishable world. “For becoming starts from non-being and advances till it reaches being and decay goes back again from being to non-being,” he wrote. That is the great beauty of it. No egg is without a parent. Everything comes out of somethi
ng that has lived before. There can be no ultimate origin or beginning.
Sometimes, by way of providing a useful counterargument to his own ideas, he might have told his students about the bold propositions of his predecessors, the pre-Socratic philosophers. There was Anaximander of Miletus, who, speculating on the origin of life three hundred years before, had proposed that all life had originated in water; that in the early years before life began, the sun’s heat had interacted with the primal mud of the earth to generate sea creatures. Some of these creatures eventually progressed to a chrysalis stage, Anaximander suggested, which hatched open to produce the first primitive humans who had clambered out of their fish-germinated chrysalis shells and onto dry land. It was a theory of great ingenuity, Aristotle might have added, but of little worth.
Then there was Empedocles of Acragas, the poet, who claimed a hundred years earlier that before humans there had been myriads of strangely shaped creatures suspended in some vast primal soup—disembodied heads, limbs, eyes—and that these body parts came together in hundreds of different strange combinations, thrown together randomly, chaotically: men with the heads of oxen, oxen with the heads of humans. The unviable combinations of body parts perished over time, Empedocles believed, while the combinations that worked survived. Aristotle thought Empedocles’ words worth quoting—but “Empedocles was wrong,” he declared in Parts of Animals. Species could not have been formed by random collisions and accidents. Democritus was wrong, too, he insisted, to declare a hundred years earlier that forms had come into being as a result of random interactions of atoms.
Such stories were wild and unverifiable, Aristotle told his students; they were no better than myths, no more verifiable than Deucalion’s stories of the flood. Nature worked according to laws that were already in operation. It was not chaotic, nor was it random, as Empedocles and Democritus had argued. Nature produced animals perfectly adapted to their environments with all the body parts they needed to survive and reproduce. Nature was perfectly designed. You had only to look at the design of human teeth to see that. How could such a structure have come about randomly, by chance or collision? Tales of species’ mutability, stories of gods and monsters and divine interventions, magical transformations and animal-human hybrids, he repeated, were tales told by soothsayers and priests. They were not stories for philosophers.
Aristotle was an intellectual risk taker and maverick. He admired the ideas of the natural philosophers who had gone before him and collected their theories. He cited them respectfully in discussion. But he accepted little as truth without having witnessed it. He might have entertained the idea of inherited characteristics or of modification with descent if someone had presented him with the proof. In mulling over the borderline creatures, he was considering zoological puzzles that would lead to evolutionary answers thousands of years later. But for Aristotle, the reason for the blurring here on the border between the animal and plant kingdoms was not that all species had evolved from common primitive aquatic life-forms, but that nature was arranged along a scale and that the blurring he saw here signified the point of transition in that scale: “For nature moves continuously from lifeless things to the animals through things that are alive but not animals,” he wrote. What he observed did not topple his absolute conviction of the fixity, regularity, immortality, and order of animal forms.
Aristotle saw corals spawn and dogfish mate, he saw the stages of the development of a chick in its egg, he saw bees dance and chameleons change color, but he did not see what we would call evolution or natural selection. Darwin was mistaken in his belief that Aristotle was the first man to publish evolutionary speculations; he was misled by James Clair Grece, the enthusiastic classicist and town clerk of Redhill, who had made an error. Grece had come across a passage of the Physics in which Aristotle seemed to be promoting what looked to him like a protoevolutionary theory. In fact, in this passage, Aristotle had been summarizing the ideas of Empedocles in order passionately to rebut those ideas. Grece mistook Empedocles’ ideas for Aristotle’s. He translated the passage and sent it to Darwin insisting, because he believed it to be true, that Aristotle had adhered to a theory of species change. Darwin, poor classical scholar that he was, believed James Clair Grece’s claim and added Aristotle to his “Historical Sketch.”
Aristotle was extraordinary and radical in his understanding of nature’s laws. He understood the principle of change to be at the heart of the natural world; he refused supernatural or mythical explanations of natural phenomena; he understood that sea and land had changed places through deep time; he saw the conceptual importance of borderline organisms; he even grasped the principle of analogous parts—that the human hand was like the fin of a fish or the wing of a bird; he understood animal-human kinship; he saw that species are continuous and gradated. But he did not believe that species had transmuted from earlier forms. In Aristotle’s world, all species were fixed within a world of unlimited duration. Individuals might change, they might evolve and metamorphose from nonbeing to being and back to nonbeing again—in that repeated arc of birth, growth, death, decay—but for Aristotle, species were beautifully, unchangeably fixed for all time. Flesh might bloom and decay, but the shape of the human body, the cicada body, the fish body—all those shapes and functions remained unchanging. Aristotle’s nature was steady-state and beautifully, eternally continuous.
Aristotle was the first to see gradation in nature. He saw nature shading almost imperceptibly in those dark seabed forms he studied in the lagoon of Lesbos with the sun beating on his back, the sponges and sea squirts and jellyfish shading from animal to vegetable and from vegetable to animal. But while later philosophers might be able to convert Aristotle’s “unbroken sequence,” his scala naturae, into the Great Chain of Being, which dominated eighteenth-century science, and which would make it easier to think or see in evolutionary ways, Aristotle did not see evolution. He held too many beliefs that were irreconcilable with evolutionary ideas. Although he had broken with Plato’s conception of ideal forms, nonetheless he believed that knowledge could be based only on what was fixed and not in flux. Only the fixity of individual forms through the eternity of species makes Aristotelian nature and thus knowledge possible.
Aristotle’s world, a seascape of enormous variety of color bounded by the shores of the Aegean, was a world of flux contained within fixed shores. Perhaps given the flux and unpredictability of his own migrant life, living as he did in the shadow of Philip of Macedonia and his soon to be imperial son, Alexander, at the mercy of a theater of war, a world in which the landscape of his childhood had been leveled in a single siege, he was bound to believe in a form of deep unchangeability.
Aristotle’s philosophical landscape differed profoundly from ours. He had different explanatory stories within which to work, different orthodoxies, different predecessors, different myths and belief systems to question or confirm. There was no orthodox account of creation in ancient Greece defended and policed by an established Church. There was no official Church-pronounced age of the earth. There was no heresy to guard against, no inquisition to fear. But there was no philosophical consensus, either. When the ancients argued about creation, their narratives were not inflected by stories of a man and a woman in a garden or a god moving across the face of the waters; their arguments turned on different questions, about whether the universe had been shaped by gods or atoms colliding chaotically or was the outcome of a design deep within all animal and plant forms.
Aristotle never returned to the intensive zoological work he had undertaken in Lesbos except to write up his lecture notes and to add more facts to the files he had already gathered. He never experienced such focused scientific work again. Philip summoned him to teach his son Alexander, who would become Alexander the Great; teaching the clever, unbridled, and energetic young man was an experiment in itself, important and challenging work. While Alexander pushed eastward, taking territory after territory right up to the borders of India, in one of the most aggressive im
perialist campaigns of history, Aristotle was safe to continue to teach in his lyceum in Athens. When Alexander died, Aristotle was forced into exile from Athens a second time, dying of natural causes at the age of sixty-two in Chalcis, a town built on a peninsula of an island and thus almost entirely surrounded by the sea.
After Aristotle died and his manuscripts and library had been stored in a cellar in Scepsis for safekeeping, where they remained underground for several hundred years, the landscapes of those quarrels and disagreements shifted again, away from the arguments that Aristotle had made for a regulated, ordered, and eternal nature. A young man named Epicurus opened a new school in Athens in 306 BC called the Garden promoting a philosophy of ethics that returned to the ideas of the atomists, arguing, as Democritus had done, that different worlds come to be and pass away as the product only of the chance collisions of atoms, not of a controlling god. Instead there was a controlling principle at work, among plants and animals, a struggle for survival that resulted in numerous adaptations and modifications as well as extinctions.
Epicurus’ writings have survived only through the retelling of Lucretius in De rerum natura and through the fragments of a thirty-seven-volume manuscript called On Nature that surfaced in the eighteenth-century excavations of a vast philosophical library in a seaside villa in Herculaneum, a library that had been engulfed by volcanic ash and lava in AD 79. Epicureanism took a short but significant hold on Roman life and ideals, but as Christianity swept across the ancient world, these notions were outlawed and denounced as pagan and materialist by Christian emperors as they closed down the academies of Greece.
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