Popular Science Monthly/Volume 26/April 1885/Aristotle as a Zoologist

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FOR over twenty centuries the philosophical writings of Aristotle have sustained his reputation as one of the greatest thinkers that the world has ever seen. Although he is generally thought of as a metaphysician and a logician, these names by no means denote the whole field of his labors. It was common for scholars in his age to take all knowledge for their province, and the limited attainments of the time allowed one writer to produce exhaustive treatises on every branch. To discover and state the laws of deduction with a completeness and accuracy which have left nothing to be added or taken away since would seem to be a sufficient labor for one man; but, besides doing this, Aristotle wrote considerable works on ethics, politics, rhetoric, physics, astronomy, physiology, and zoology. There is not the same unanimity, however, in estimating his scientific achievements as in the opinion of his writings on logic and speculative philosophy.

Aristotle's "History of Animals," says Buffon, "is, perhaps, even now the best work of its kind; he probably knew animals better, and under more general views, than we do now. Although the moderns have added their discoveries to those of the ancients, I do not believe that we have many works on natural history that we can place above those of Aristotle and Pliny." The laudatory language of the illustrious Cuvier is equally strong. Of the "History of Animals" he writes: "I can not read this book without being ravished with astonishment. Indeed, it is impossible to conceive how a single man was able to collect and compare the multitude of particular facts implied in the numerous general rules and aphorisms contained in this work, and of which his predecessors never had any idea." Again, "Not only did he know a great number of species, but he studied and described them after a vast and luminous plan which, perhaps, none of his successors have approached. . . . Everywhere Aristotle observes facts with attention." On the other hand, Lewes, in his essay on Aristotle, says: "It is difficult to speak of Aristotle without exaggeration—he is felt to be so mighty, and is known to be so wrong. History, surveying the whole scope of his pretensions, gazes on him with wonder. Science, challenging these separate pretensions, and testing their results, regards them with indifference—an indifference only exasperated into antagonism by the clamorous urgency of unauthenticated praise. It is difficult to direct the opposing streams of criticism into the broad, equable current of a calm appreciation, because the splendor of his fame perpetuates the memory of his failure, and to be just we must appreciate both. His intellect was piercing and comprehensive; his attainments surpassed those of every known philosopher; his influence has only been exceeded by the great founders of religions. Nevertheless, if we now estimate the product of his labors in the discovery of positive truths, it appears insignificant when not erroneous. None of the great germinal discoveries in science are due to him or to his disciples." The question to be decided does not concern Aristotle's splendid and perhaps unrivaled genius, his logical power of thought, his love of truth, and his extraordinary diligence; it has reference to the claim made by Aristotle's too ardent panegyrists, that he discovered a system so perfect as to leave little, if anything, for us to alter, that in several instances he anticipated modern discoveries, and that his descriptions are marvels of accuracy and research. How far such statements are true must be discovered by the simple test of reading Aristotle's own words, and for this purpose some of the extracts employed to illustrate a recent comparison of the above conflicting opinions in the "Edinburgh Review" will be instructive.

Let us inquire how far Cuvier's statement that "everywhere Aristotle observes facts with attention" is true. In describing the elephant, Aristotle tells many things correctly, but some very incorrectly, so that it is a question whether he ever saw this animal in his life. He affirms that it has no nails on its toes, though he correctly refers to the toes, which are scarcely distinguished. The nails of the elephant are one of the "points" which the natives of India always regarded as marks of a well-bred animal, and are usually conspicuous. Let us take another point, the "gray-headed error" that the elephant has no joints. Aristotle says, "The elephant is not so constructed as to be unable to sit down and bend his legs, as some persons have said, but from his great weight he is unable to bend them on both sides at once, but leans either to the right side or the left, and sleeps in this position." That is to say, the elephant, having bent one fore-leg, can not then bend the other so as to kneel with both, which is contrary to fact. Although in this passage Aristotle demolishes the absurd statement that the elephant has no knee-joints, yet, in his treatise on the "Progressive Motions of Animals," he seems to leave the matter in doubt. After showing that without inflection there can be no progression, he says: "Progression, however, is possible without inflection of the leg, in the same manner as infants creep; and there is an ancient story of this kind about elephants, which is not true, for such animals move because inflection takes place in their shoulder-blades or hips." The existence of animals without knees is again supposed by this remark: "Since the members are equal, inflection must be made in the knee, or in some joint, if the animal that walks is destitute of knees." If Aristotle had ever seen an elephant move, is it not probable that he would have spoken more decidedly and correctly on these points? But the most astonishing assertion is that "the elephant can not swim on account of the weight of its body"!

Aristotle's account of the camel is, on the whole, graphic and correct; he describes both the one-humped Arabian and the Bactrian species. He mentions the walk of the camel, stating that it moves with the hind-foot following the fore-foot on the same side. He twice repeats the statement that the camel has no teeth in the upper Jaw. Doubtless he alludes to the front teeth; but the camel has two incisors in the upper jaw and two canines, so that Aristotle has not, as Cuvier asserts, "perfectly described and characterized the two species of camel." Among other strange notions held by Aristotle, apparently without any misgivings, may be mentioned the lion having no cervical vertebræ, but only one bone in the neck, its bones, which are small and slight, being without marrow, except a little in the thigh and foreleg. In his work on "Parts of Animals," he joins wolves with lions in having one neck-bone, and gives as a reason, "Nature saw that these animals wanted the neck more for strength than for other purposes." Aristotle's notions with respect to the skull are peculiar; the brain is placed beneath the sinciput, and the occiput is empty—an error twice repeated. Women's skulls have only one suture, in the form of a circle. He mentions as an extraordinary thing the fact of a man's skull having once been seen without any suture, copying Herodotus in this, who says such a skull was found on the battle-field of Platæa. The skull-sutures in aged persons are frequently obliterated. Again, "The cranium of the dog consists of a single bone." He must have got hold of an old specimen. Certain abnormal deposits of bone which occasionally are found with diseased conditions of the heart in some of the mammalia were considered as necessary organs in the horse and some kind of oxen, "which on account of their large size have a bony heart for the sake of support." The seal and some swine are said to have no gall-bladder. The gall-bladder is by no means constant in the mammalia, and Aristotle is correct in saying it is not present in the elephant, stag, horse, ass, and mule. It is difficult to know what he means when he says that the Achaïnian stags appear to have a gall in the tail; we are quite in the dark as to what these stags are. In another place he mentions a stag of the same kind, which when captured was found to have a considerable quantity of green ivy growing on its horns as on green wood. Buffon seems to have thought this story possible.

That Aristotle placed too much reliance on the marvelous and impossible animal lore current in his age is obvious. Speaking of the male stag shedding his horns he writes, "It is said that the left horn has never yet been seen, for the animal hides it because it has some medical properties." "When stags are bitten by the phalangium or other such creature, they collect a number of crabs and eat them." These statements are made by Aristotle without a single hint that he does not believe them. Had he regarded them as fabulous, it is probable that he would have so intimated, as he is in the habit of doing when he regards stories as "unworthy of credit." Mr. Lewes mentions Cuvier's instancing four generalizations to prove the immense acquaintance Aristotle must have had with particulars, and adds: *' I will quote four others (forty might be found), all taken from the first book, which exemplify plainly enough how easily large and careful induction could be dispensed with: 1. The lion has no cervical vertebrae, but a single bone in its neck. 2. Long-lived persons have one or two lines which extend through the whole hand; short-lived persons have two lines, and these do not extend through the whole hand. 3. Man has, in proportion to his size, the largest and the moistest brain. 4. The forehead is large in stupid men, small in lively men, broad in men predisposed to insanity, and round in high-spirited men."

Aristotle's account of the halcyon, or kingfisher, is a curious mixture of fact and fiction, the latter largely predominating. He gives a good popular description of the bird, but says also: "Birds generally breed in the spring and the beginning of summer, but the kingfisher is an exception, for it produces its young about the time of the winter solstice; wherefore fine days which happen at this season are called halcyon days, seven days before the solstice and seven days after it, as Simonides has written, as when Jupiter in the winter month prepares fourteen days, which mortals call the windless season, the sacred nurse of the variegated halcyon. . . . These halcyon days do not always happen in this country at the season of the solstice, but they nearly always occur in the Sicilian Sea." He has some curious stories about eagles, and here, too, seems to depend upon the poets: "The eagle lays three eggs, but hatches only two, as is also related in the poems of Musæus, 'the bird which lays three eggs, hatches two and cares only for one.' Such things often occur, yet even three young ones have been seen in the nest. . . . The sea-eagle is very quick sighted, and compels its young ones while still naked to look at the sun, and if one of them will not do so it beats it and turns it round; and the young one which first weeps it kills, the other it rears."

Among other curious zoölogical statements of Aristotle's which seem to receive his support, and which may be set down as current folk-lore of his time, are the following: "If any one make a noise as grasshoppers fly along, they emit a kind of moisture, as agriculturists say. They feed on dew, and if a person advances to them bending his finger and then straightening it, they will remain more quiet than if the finger is put out straight at once, and will climb up the finger, for from bad sight they ascend it as if it were a moving leaf." "Persons who have parasites in the head are less subject to headache. Moths are produced in the greatest abundance if a spider is shut up with them in the wool, for this creature being thirsty dries up any moisture which may be present. Small birds during the day fly round the owl—which is called admiring it—and as they fly round it they pluck out its feathers." "The anthus" (some bright-colored bird) "is an enemy to the horse, for it drives the horse from its pasture and eats the grass; it imitates the voice of the horse and frightens it by flying at it, but when the horse catches it he kills it." "If any one takes hold of a she-goat by the long hairs of the beard, all the others stand still as if bewildered and gaze at her." "The hawk, though carnivorous, does not eat the hearts of the birds it has killed." "The jay has many varieties of voice; it utters a different one, so to speak, every day." "The goat-sucker flies against the she-goats and sucks them, whence its name. They say that, after the udder has been sucked, it becomes dry and goes blind." "Mares become less ardent and more gentle if their manes are cut. At certain times they never run to the east or west, always north or south." "The sow gives the first teat to the first little pig that is born." "When a serpent has taken its food, it draws itself up till it stands erect upon its tail."

Aristotle's reasons are frequently amusing. Man has no tail because the available formative material has been used up for the posterior parts. Apes have neither tail nor buttocks because they are intermediate between man and quadrupeds. Bees and wasps have stings inside their bodies because they have wings. All crabs and lobsters (generally) have the large claw on the right, because all animals are by nature strong on the right side. Bees and ants are more intelligent than other animals of the kind, because their blood is thin and cold. The seal has no external ears, only ear-pores, because its feet are incapacitated for walking. Serpents have a forked tongue because they are gluttonous, and a bifid tongue has a double tasting power. Man is the only animal that is tickled, because his skin is fine; and he is the only animal that laughs, and tickling is "laughter from a motion of this kind about the arm-pit," which, as Mr. Lewes says, is "a physiological explanation rather difficult to understand." Insects eat little because their bodies are cold. It is curious to notice that Aristotle had no idea that insects produced eggs; he said they bring forth worms, evidently taking the larva stage for the normal birth-form.

These instances are taken from the treatise on "Parts of Animals." It would be easy to supply many more of the same character, but surely these may incline us to deny that "in his accumulation of facts Aristotle has not written one useless word." It is certain from Aristotle's remarks, here and there, that he occasionally dissected animals, but he also mentions anatomical drawings as existing in his time, and refers bis readers to them. He could not, however, have dissected to any great extent, or he would not have made the erroneous assertions that he has on many points not difficult of demonstration. It seems to be chiefly among marine animals that he practiced dissection, and to which he paid most personal attention; certainly, many of his observations on sponges, Crustacea, cephalopoda, and other sea creatures, are admirably correct. To the question, did Aristotle dissect human bodies? his many misstatements seem to require a negative answer; at any rate, as Mr. Lewes remarks, "An answer in the affirmative would be still more damaging to his reputation, since it would render many of his errors unpardonable."

There seems much reason to believe that he paid little attention to examining the skeletons of animals, and that his osteological knowledge was very limited. Let us consider what he has recorded of a certain bone, well known to the Greeks as being one much used for dice and some other purposes. "Many cloven-footed animals," he says, "have an astragalus, but no many-toed animals have one, neither has man; the lynx has, as it were, half an astragalus, the lion one in the form of a coil; solid-hoofed animals, with the exception of the Indian ass, have no astragalus; swine have not a well-formed astragalus." The fact is that the hind-feet of all mammals possess this bone, with slight differences in form and relative position with the other tarsal bones, but always preserving its characteristic shape. Aristotle had a theory—a kind of physiological axiom—which led him to infer that certain animals could not have an astragalus, and he did not examine them to verify his theory; he was satisfied that his theory proved his facts, and that there was no need of verification. His argument, gathered from several passages, is mainly as follows: Large animals have in their system much earthy matter, the superabundance of which Nature uses in the formation of teeth, tusks, and horns. In solid-hoofed animals, as the horse, the excess of earthy matter goes to form the hoof, and not horns or tusks as it does in cattle and elephants; and, as this excess is spent in the formation of a solid hoof, such animals have no astragalus, which is only a kind of superadded bone, and would be, in the horse, for instance, a detriment rather than an advantage.

Aristotle had an ardent love and admiration of Nature, and in Nature he always saw the beautiful. He gives expression to this feeling in the following admirable passage from the "Parts of Animals": "Having already treated of these subjects, and given what is our opinion about them, it remains for us now to speak of animated nature, omitting nothing, as far as lies in our power, whether it be ignoble or honorable; for, even in those things which seem less pleasing to our senses in our contemplation of them, Nature, the creator of all things, affords inconceivable pleasures to those able to discover the causes of things and are philosophers by nature. For it would be unexpected and strange, indeed, if, when looking at images of things, we rejoice when we survey the art that produced them, whether in painting or sculpture, and do not rather love the sight of the actual works of Nature when we are able to discover their causes."

Dr, Ferdinand Hoefer, writing on Aristotle in the "Nouvelle Biographic Universelle," says, "It is the part of men of genius to show equal superiority in every field," and many of Aristotle's eulogists write as if to abate one jot of this thesis would be treason to their idol. They outdo the zealous friend of Miles Standish in

"Praising his virtues, transforming his very defects into virtues,"

and are frequently carried into absurdities. To quote one other instance from Hoefer, "We find among others this remarkable (!) statement, that animate bodies are composed of air and water. As a fact, chemists have shown that all organic bodies are reduced by analysis to the elements of air and water (oxygen, carbon, hydrogen, and nitrogen)." Now Aristotle's notion of elements was that there were four, having respectively the characters of air, water, earth, and fire, or hot moisture, cold moisture, cold dryness, and hot dryness; and he conceived that animal substances combined the qualities of the first two. A glance at the percentage compositions of air, water, and an animal body puts Hoefer's coincidence in a still worse light. A favorite defense of Aristotle is to suggest that the erroneous passages have been interpolated—so sublimely confident are his disciples that Aristotle can not be wrong, and that what is wrong can not be Aristotle. Then, too, we are bidden to consider the state of science in his day. But, unless Aristotle made a decided advance on the state of science in his day, why call him a great naturalist? Just how much better he observed and experimented than the writers on natural science who immediately preceded him, it is impossible to say, since their books, to which he often refers, are lost. Certainly, he failed to record any adequate understanding and appreciation of these processes, and the world has had to learn them from later thinkers. His most ardent admirer will not claim to find in his writings an exposition of inductive reasoning to be compared with his exposition of the deductive process. His mind seems to have had such a pre-eminent command and comprehension of deductive reasoning—it was so perfectly adapted to run in deductive grooves, as it were—that it was incapable of more than the most imperfect use or conception of induction. Without a good command of the tools of science—observation, experiment, and induction—his scientific work could not be important.

But the reputation of Aristotle can well afford to dispense with these contested ascriptions. Sufficient remains unimpeachable to vindicate his title to a gigantic intellect, and let no one suppose that they who deny him equal eminence in widely unlike fields can be outdone in their honor of his real genius.