Modern evolutionary biologists demur. They point out that ‘good of the species’ arguments are weak and at best a last resort. They argue instead that ageing is the result of the absence of natural selection. Most animals and plants have a constant risk of death from external causes such as accident and disease and since the dead cannot reproduce old age is invisible to natural selection. This invisibility means that bodies are designed to work when young but fall apart when old. When, therefore, we ask what ageing is for we must give the peculiar answer that it isn’t for anything; it is, instead, the evolved consequence of there being no reason to stay alive.
There is, however, a bit more to be said about Aristotle’s account of the ultimate reason we fall apart. For it is not merely living things that are subject to the forces of destruction: every natural object under the light of the moon is. Animals, plants, tissues, rivers, rocks, the very elements themselves are forever decaying. But this isn’t the Second Law of Thermodynamics avant la lettre for, in Aristotle’s world, everything that is destroyed is regenerated again, even if only as another individual of the same form. More than that: the finite span of any creature’s life is a consequence of the perpetual elemental turmoil within. The ultimate reason, then, that we must be born, live, age and die is that we, too, are held in the swirling embrace of the cycles of the physical world.
LXXXVI
THERE IS A story of Lesbos that depicts the island as it was nearly two millennia ago.
Two children, a goatherd and a shepherdess, are herding their animals in the hills beyond Mytilene. They started life as foundlings, were raised in humble homes, but now are grown to uncanny adolescent beauty. The flowers are in bloom; the bees buzz in the meadows; songbirds fill the woods. Infected by the season, the youths gambol like lambs, catch crickets and weave flowers into garlands. Together they steal into the woods until they reach a vast hollow boulder from which a rivulet emerges on to a mossy sward. It is a sanctuary: statues of Nymphs (bare arms, loose tresses, belted waists) stand poised in a frozen circular dance amid flutes and panpipes left by generations of shepherds. Daphnis bathes, innocent as a fish; Chloe is stung by love; the smiling Nymphs watch, flowers draped around their stone necks.
Some scholars dismiss the pastoral landscape described by Longus in his novel as an idyllic invention. Others, however, say that the geography is true to life. One even places Daphnis and Chloe’s grotto as the source of the Vouváris in the hills to the south-east of the Lagoon. For my part, I favour the waterfalls at Pessa, fed by the adjacent Mákri, where there are deep rock pools shaded by pines and inhabited by tiny freshwater crabs. It’s where the local youths now go to bathe. But the exact location of the grotto doesn’t really matter. It is, after all, just a story. What matters is that, once again, it is spring.
THE STONE
FOREST
HIPPOKAMPOS – SEA HORSE – HIPPOCAMPUS SP.
LXXXVII
SKALA KALLONI’S RESIDENT pelican was called Odysseus and lived in a kennel by the beach. He belonged to the peripheral economy of pets and strays that depends on the unsaleable fish that are occasionally thrown their way. I have seen the pelican, six cats and a collie staring at the rigging of a single boat – apparently owned by a fisherman of famous generosity – with the blank optimism of commuters waiting for the tube. Odysseus would gape and try to field the fish thrown his way; but pelicans, or perhaps just this pelican, have poor bill–eye co-ordination and so he had learnt to pick them up from the wharf, a manoeuvre that involved neck-twisting contortions for which he was obviously not designed.
Odysseus was an arrogant beauty with pink-flushed plumage and a lemon-yellow bill. But he also had an air of pathos for he had only one leg. If a fish intended for him fell into the water, he would merely stand on the harbour wall and morosely watch it sink. On summer days I have sometimes stretched out on the warm stone wharf to look into the water’s depths. Odysseus would then hop over and, out of boredom or misanthropy, gnaw on my shoes until told sternly to desist, at which point he would ruffle his feathers and glare at me with his tiny bloodshot eyes.
Skala’s harbour teems with larval fish, too small to identify, that are chased about by flickering schools of small silvery sea bream that are, in turn, preyed upon by the resident squadron of implacable black cormorants. Just beneath the water’s surface the walls of the wharf are covered with a brown alga amid which dozens of hermit crabs clamber about, their tomato-red claws vivid against the chalk grey of their worm-eaten shells. They are clumsy and the sea anemones that they carry about on their shells don’t help. The anemones are called Calliactis parasitica, but they are mutualists that protect the crab with their stinging nematocysts and receive, in return, a movable feast.
Further down the wall the community becomes richer. Black mussels, crystalline sea squirts, hydrozoan colonies spun of gold and yellow threads, green and brown masses of sponges compete for Lebensraum. Small spider crabs amble past herds of Holothuria forskali. I once grabbed one of the flaccid creatures and asked a fisherman, mending his nets, the local name. ‘Gialopsolos – know what that means?’ Yes – sea cucumbers are also sea pricks everywhere. Unusually, Kalloni also has a gialopmoya or sea cunt, a large, beautiful but noxious scyphozoan jellyfish. It has a deep orange bell that pulses gently and tentacles which stream behind it a metre long.
There are also seahorses down there. You don’t often see them from the wharf, but they’re caught in the nets and, since not even the cats can eat them, just discarded. Often I found them expiring in the sun, flexing their armoured tails in a vain search for something to coil about. I always threw them back but, I suspect, to no good end for they never righted themselves and whirred away, but just spiralled limply into the gloom.
Skala has no archaeology, so let us place Aristotle at Pyrrha, the small polis on the Lagoon’s south-eastern shore. It is a sweet early-summer morning and the sea is flat. Sirios, the Dog Star, which rose just before dawn, has disappeared in the sharpening sun. Aristotle has, perhaps, breakfasted on figs and honey and milky cheese, but now he’s sprawled, face down, on Pyrrha’s stone wharf, an irate pelican molesting his feet, pulling up sponges, sea anemones and sea squirts. Ripped from the water, dumped on the stone, they form a gelatinous mess, a bit repulsive to the touch.
Aristotle has an ontological problem with sponges. It’s not that they were unfamiliar since they were found in every household. In the Odyssey sponges are used to cleanse the suitors’ stains from the furniture. In Agamemnon Aeschylus compares death to a sponge that wipes all our mortal traces away. No, Aristotle is perfectly well acquainted with sponges; his problem is that he’s unsure whether they are animals or plants.
His world seems so neatly structured. Sharp lines divide the living and the dead, the animal and the vegetable. In his official ontology living things have souls, dead things don’t; animals have sensitive souls, plants do not. No one could mistake a stone for an olive tree or an olive tree for a goat. It all seems very clear. Until we get to sponges. On the one hand sponges are like plants since they’re rooted to the rocks from which they grow, and from which they presumably get their nutrition. On the other they do one very unplant-like thing: they can sense, and respond to, touch. People say – Aristotle’s reporting a diver’s tale – that if a sponge becomes aware that it’s about to be plucked from a rock, it will contract and resist. He adds that the people of Torone deny this, but that everyone agrees that the aplysia (Sarcotragus muscarum?) can sense touch.*
It’s not just sponges that seem to bridge the plant/animal divide. Look into the harbour and it’s all ambiguity. The tēthya (sea squirts), knidai and akalēphai (sea anemones), holothourion and pneumōn (either or neither of which might be, from his meagre descriptions, a sea cucumber or a jellyfish) and the pinna (giant fan mussel) are all dualizers, but of a much more radical sort than a dolphin, ostrich or bat. Other ambiguous things grow in more distant seas. Theophrastus tells of a stony, scarlet, deep-sea growth. He calls it the kor
allion and means the precious red coral, Corallium rubrum. He speaks about it in his book on stones, between pearls, lapis lazuli and red jasper. Is coral, then, a mineral? Probably not – for it appears again in his Enquiries on Plants as a kind of deep-sea plant that grows near the Straits of Gibraltar and that resembles a sow thistle. There are also tree-like growths in the Gulf of Heroes that are about three cubits (135 centimetres) high, resemble stone when they emerge from the sea and display vivid flowers when submerged. Theophrastus has heard of the great fringing coral reefs that run for two thousand kilometres from Aqaba to the mouth of the Red Sea.
Animals have three faculties that plants don’t: sensation, appetite and locomotion. They are all faculties of the sensitive soul. All of Aristotle’s plant–animal dualizers lack at least one. Sea squirts are sessile but respond to touch; sea anemones are also sessile but can, sometimes, detach themselves and grab their food; the holothourion and the pneumōn are free living and can move, or at least flop, about but don’t have perception; the fan mussel, one of the ostrakoderma and therefore similar to snails and oysters, is ‘rooted’ in the ground like a plant (he means the anchoring byssal threads). Since all of these creatures have at least one faculty of the sensitive soul, Aristotle probably supposes that they are, on balance, animals. But he never really says so. That’s because he’s less interested in the solution to the taxonomic problem than in the reason it’s a problem at all. The really interesting point is this:
Nature proceeds from the inanimate to the animals by such small steps that, because of the continuity, we fail to see to which side the boundaries and the middle between them belongs. For, first after the inanimate kind of things is the plant kind, and among these one differs from another in seeming to have more share of life; but the whole kind in comparison with the other bodies appears more or less as animate, while in comparison with the animal kind it appears inanimate.
The living and the dead, the plant and the animal, form a finely graded continuum. At one end are inanimate, almost formless entities such as stones; at the other, animals running on bi- or even tripartite souls. As one moves along this continuum, from dead things to plants to animals, the characteristic features of each class appear in a step-wise fashion. But the fact remains: it’s hard to draw lines in the sea.
LXXXVIII
‘NATURE PROCEEDS . . . by such small steps.’ Or, to express the same thought obversely and in Latin, Natura non facit saltum – nature does not jump. The tag is familiar. It was one of Darwin’s favourite slogans; in the Origin alone it appears seven times. Huxley, famously, thought it a needless weakness of the theory.* It is a recurring motif in Aristotle too: explicitly when he speaks of plant-like sponges or how, in some animals, bone seems to blend into fishbone; implicitly when he says that snakes are elongate lizards (are, indeed, their ‘kindred’), that seals are ‘deformed’ tetrapods and that apes seem so nearly human.
It’s not just a matter of a single slogan. When you read Aristotle you can’t help but be reminded of Darwin. Aristotle constructs hierarchical classifications and uses the word genos – family – for his taxonomic category. That seems to imply similarity by descent, for what is a family if not a group of genealogically related things? He distinguishes between analogous parts and those that ‘are the same without qualification’ – that is, parts that are homologous. What meaning can that possibly have if not an evolutionary one? So, too, his account of how the embryos of different animals are remarkably similar when they first form and only later diverge. As von Baer’s ‘First Law’ of embryology it was one of Darwin’s most telling bits of evidence for evolution.
And then, in the writings of both men, there are the explanations by the dozen of how this or that animal’s organs are designed to work with each other or in the particular environment in which it lives. Many philosophers and scientists have tried to draw a line between Aristotelian teleology and Darwinian adaptationism. (‘Teleonomy’, an ephemerally popular weasel-word, was coined to invoke teleology without being too blatantly Aristotelian.) Such semantic quibbles obscure the similarities. Aristotle’s functionalism is as resolute as Darwin’s – and that of most evolutionary biologists.
Indeed, reading Aristotle, it’s easy to suppose that he is struggling towards, or even has, a theory of evolution. He isn’t and hasn’t. Nowhere in his works does he claim, as Darwin did, that all animals are descended from some remote common ancestor. Nowhere does he suggest that one kind of animal can transform into another. Nowhere does he lament some kind that has gone extinct. Genos, he says, is a word that can be used in several different senses – but there’s no hint that, in the biology, he’s using the genealogical one. When he says that ‘nature makes small steps’ he means it in a static sense – that one can observe fine gradations between forms. Darwin means it dynamically – that species can transform, but do so gradually. Nowhere does Aristotle appeal to anything resembling natural selection as a force for either stasis or change.
Yet he had all the ingredients. Natural selection is an explanation – the only rational one going – for adaptation. Aristotle understands adaptations and grasps that they must be explained. As scientific explanations go, natural selection is simplicity itself, requiring only a grasp of three concepts: that creatures are variable, that at least some of this variation is inherited and that some of these variants survive and reproduce by virtue of their phenotypes while others do not. Aristotle’s own theory of quasi-stable inheritance gives him the first two; Empedocles’ selectionism gives him the third. Aristotle, it seems, lacks nothing but the insight, or perhaps the will, to put them together.
It is a diverting though perhaps futile game, to speculate why this is so. After all, a prepared mind may be necessary for the formulation of a new idea, but it is clearly not sufficient. Did not Huxley declare, upon having natural selection explained to him, ‘How stupid of me not to have thought of that’? Hindsight is so easy.
And powerful. It is not impossible for a biologist to read Aristotle and put all thoughts of evolution out of mind, but it is very hard. Evolution underpins all our theories and explains all our observations. We see its handiwork everywhere. We are bred to do so as greyhounds are to run. And there is another difficulty. Darwin looms so vast against his predecessors that we tend to credit him for everything. Historians write of German Naturphilosophen and French transcendental anatomists but, as far as biologists are concerned, they write in vain – 1859 remains year zero. ‘Ever since Darwin . . .’ – it is our story, our origin myth. It is not one that I would, or could, destroy. But I do ask this. Should you come across an apparently Darwinian thought in Aristotle, pause and reflect that you may be recollecting an Aristotelian thought in Darwin.
LXXXIX
IF THIS IS SO, it is not so because Darwin had read much Aristotle. Transmutation Notebook C contains a promissory note: ‘Read Aristotle to see whether any my views is ancient?’ It’s dated June 1838, about two years after the Beagle had reached Falmouth. After that there is little more until the fourth edition of the Origin, 1866, in which, discussing some possible proto-evolutionists, Darwin quotes a knotty bit of Physics II, 8 – Aristotle on Empedoclean selectionism. But he did so only because a correspondent had sent him the passage and he rather muddles it up. In fact it is certain that Darwin knew little about Aristotle that wasn’t fragmentary or second-hand before 1882 which is when William Ogle, physician and classicist, sent him a copy of The Parts of Animals that he had just translated along with the following letter:
Dear Mr. Darwin,
I have given myself the pleasure of sending you a copy of a translation of ‘De Partibus’ of Aristotle; and I feel some self-importance in thus being a kind of formal introducer of the father of naturalists to his great modern successor. Could the meeting occur in the flesh, what a curious one it would be!
Ogle’s translation is lovely. Truer translations, with deeper commentaries, have since been made; but just as D’Arcy Thompson illuminated Historia animali
um with a naturalist’s insight, so Ogle illuminated The Parts of Animals. When Aristotle tells us that ‘All female quadrupeds void their urine backwards, because the position of the parts that this implies is useful to them in the act of copulation,’ Ogle has a footnote to tell us that this is so.
It was just the book to send to Darwin. A few weeks later, Darwin replied to Ogle thanking him for the book:
From quotations which I had seen I had a high notion of Aristotle’s merits, but I had not the most remote notion what a wonderful man he was. Linnaeus and Cuvier have been my two gods, though in very different ways, but they were mere school-boys to old Aristotle.
This, by his own account, is when they first truly met. And though we would love to know what Darwin thought as he read The Parts of Animals and encountered one of the few minds in history that equalled his in scope and power, and then on the same subject, sadly we do not. Darwin’s reply to Ogle was one of the last he ever wrote, for by April of that year he was dead. It may seem, then, that my suggestion that Darwin’s works are infused with Aristotle is no more than wishful thinking, but that is not so. When Darwin said that his ‘two gods’ – Linnaeus and Cuvier – were mere schoolboys compared to Aristotle, he was insufficiently precise. He should have said that old Aristotle taught them.
XC
ARISTOTLE’S CLASSIFICATION OF the animals is the starting point of our own. Linnaeus got many of his European species from him, either directly or via the sixteenth-century encyclopaedists. The vaults of the Linnean Society at Burlington House, Piccadilly contain Linnaeus’ copy of Aristotle’s zoological works (Gaza’s translation, printed at Venice in 1476), and his copy of Gesner’s Historia animalium. You can follow their names through the successive editions of Systema naturae until they appear as modern species in the magisterial tenth. Aristotle speaks of the sēpia; Gesner of the Sepia; Linnaeus (1758) of Sepia officinalis – the name by which we know the cuttlefish today.
The Lagoon Page 27
