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entitled to the place which is usually as- | alleged fact by a rambling assemblage of signed to Bacon as the father of the induc. absurd “notions.” And numerous other tive methods; while, on the other hand, it instances might be given to the same is maintained that in respect of method he effect. Nevertheless, upon the whole, or did not make any considerable advance as a general rule, in his thought and lanupon his predecessors. In my opinion a guage, in his mode of conceiving and just estimate lies between these two ex. grappling with problems of a scientific tremes. Take, for example, the following kind, in the importance which he assigns passages from his writings :
to the smallest facts, and in the general We must not accept a general principle cast of reasoning which he employs, Aris. from logic only, but must prove its applica- totle resembles, much more closely than tion to each fact, for it is in facts that we must any other philosopher of like antiquity, a seek general principles, and these must always scientific investigator of the present day. accord with facts. The reason why men do not sufficiently at of Aristotle's work in natural history, we
Thus, in seeking to form a just estimate tend to the facts is their want of experience. must be careful on the one hand to avoid Hence those accustomed to physical inquiry the extravagant praise which has been lav. are more competent to lay down the principles which have an extensive application; ished upon him, even by such authorities whereas others who have been accustomed to as Cuvier, De Blainville, Isidore St. many assumptions without the apposition of Hilaire, etc.; and, on the other hand, we reality, easily lay down principles because must no less carefully avoid the unfairness they take few things into consideration. It is of contrasting his working methods with not difficult to distinguish between those who those which have now become habitual. argue from facts, and those who argue from notions.
In proceeding to consider the extraor. Many similar passages to the same dinary labors of this extraordinary man, effect might be quoted, and it is evident in so far as they were concerned with nat. that the true method of inductive research ural history, I may begin by enumerating, could not well have its leading principles but without waiting to name, the species more clearly enunciated. And to say this of animals with which we know that he much is in itself enough to place Aristotle was acquainted. From his works on natin the foremost rank among the scientific ural history, then, we find that he menintellects of the world. But it would be tions at least seventy species of mammals, unreasonable to expect that this great one hundred and fifty of birds, twenty of herald of scientific method should have reptiles, one hundred and sixteen of fish, been able, with any powers of intellect, to eighty-four of articulata, and about forty of have entirely emancipated himself from lower forms – making close upon five hun. the whole system of previous thought; or dred species in all. That he was accusin the course of a single lifetime to have tomed from his earliest boyhood to the fully learnt the great lesson of method anatomical study of animal forms we may which has only been taught by the best infer from the fact of his father having experience of more than twenty centuries been a physician of eminence, and an after his death. Accordingly we find that, Asclepiad ; for, according to Galen, it was although he clearly divined the true prin- the custom of the Asclepiads to constitute ciples of research, he not unfrequently fell dissection part of the education of their short in his application of those principles children. Therefore, as Aristotle's boy. to practice. In particular, he had no ade. hood was passed upon the seacoast, it is quate idea of the importance of verifying probable that from a very early age his cach step of a research, or each stateinent studies were directed to the anatomy and of an exposition; and therefore it is pain: physiology of marine animals. But, of fully often that his own words just quoted course, it must not be concluded from this admit of being turned against himself: that the dissections then practised were “It is easy to distinguish between those comparable with what we understand by who
argue from facts and those who argue dissections at the present time. We find from notions.” To give only a single ex- abundant evidence in the writings of Arisample, he says that if a woman who has totle himself that the only kind of anatscarlet fever looks at herself in a mirror, omy then studied was anatomy of the the mirror will become suffused with a grosser kind, or such as might be prosebloody mist, which, if the mirror be new, cuted with a carving-knife as distinguished can only be rubbed off with difficulty. from a scalpel. Now, instead of proceeding to verify this We generally hear it said that as a nat. old wife's tale, he attempts to explain the luralist Aristotle was a teleologist, or a
believer in the doctrine of design as man- a designiog or contriving agency, having ifested in living things. Therefore I the attainment of order and harmony as should like to begin by making it clear the final end or aim of all her work. He how far this statement is true; for, un appears, however, clearly to have recog. questionably, when such an intellect as nized that, so far at least as science is that of Aristotle is at work upon this im- concerned, such personification is, as it portant question, it behoves us to consider were, allegorical ; for he expressly says exactly what it was that he concluded. that if he were asked whether nature
Now, I do not dispute - indeed it would works out her designs with any such conbe quite impossible to do so - that Aris. scious deliberation, or intentional adjusttotle was a teleologist, in the sense of be- ment of means to ends, as is the case with ing in every case antecedently convinced a builder or a shipwright, he would not be that organic structures are adapted to the able to answer. All, therefore, that the tele. performance of definite functions, and that ology of Aristotle amounted to was this: the organism as a whole is adapted to the he found that the hypothesis of purpose conditions of its existence. Thus, for ex- was a useful working hypothesis in his ample, he very clearly says: “As every biological researches. There is nothing instrument subserves some particular end, to show that he would have followed the that is to say, some special function, so natural theologians of modern times, who the whole body must be destined to min- seek to rear upon this working hypothesis ister to some plenary sphere of action. constructive argument in favor of design. Just as the saw is made for sawing - this On the other hand, it is certain that he being its function — and not sawing for would have differed from these theolothe saw."
gians in one important particular. For he But in any other sense than this of rec- everywhere regards the purposes of nature ognizing adaptation in nature, I do not as operating under limitations imposed by think there is evidence of Aristotle having what he calls absolute necessity. Monbeen a teleologist. In his “ Metaphysics sters, for example, he says are not the he asks the question whether the principle intentional work of nature herself, but of order and excellence in nature is a self-instances of the victory of matter over existing principle inherent from all eternity nature; that is to say, they are instances in nature herself; or whether it is like the where nature has failed to satisfy those discipline of an army, apparently inherent, conditions of necessity under which she but really due to a general in the back-acts. Thus, even if there be a disposing ground. Aristotle, I say, asks this ques- miod which is the author of nature, action; but he gives no answer. Similarly, cording to Aristotle it is not the mind of in his “ Natural History," he simply takes a creator, but rather that of an architect, the facts of order and adaptation as facts who does the best he can with the mateof observation; and, therefore, in biology rials supplied to him, and under the conI do not think that Aristotle can be justly ditions imposed by necessity. credited with teleology in any other sense than a modern Darwinist can be so cred- Turning now to the actual work which ited. That is to say, he is a believer in Aristotle accomplished in the domain of adaptation, or final end; but leaves in biology, I will first enumerate bis more abeyance the question of design, or final important discoveries upon matters of
The only respect in which he fact, and then proceed to mention his differs from a modern Darwinist — al- more important achievements in the way though even here the school of Wallace of generalization. and Weismann agree with him — is in He correctly viewed the blood as the holding that adaptation must be present medium of general nutrition, and knew in all cases, even where the adaptation is that for this purpose it moved through the not apparent. In the case of rudimentary blood-vessels from the heart to all parts organs, he is puzzled to account for struc- of the body, although he did not know that tures apparently aimless, and therefore he it returned again to the heart, and thus invents what we may term an imaginary was ignorant of what we now call the cir. aim by saying that nature has supplied culation. But he was the first to find that these structures as “tokens,” whereby to the heart is related to the blood-vascular sustain her unity of plan. This idea was system; and this he did by proving, in prominently revived in modern pre-Dar- the way of dissection, that its cavities are winian times; but in the present connec- continuous with those of the large veins tion it is enough to observe that here, as and arteries. Nor did he end here. He elsewhere, Aristotle personifies nature as traced the course of these large veins and
arteries, giving an accurate account of attributing the formation of urine to the their branchings and distribution. He bladder, seeing that he had gone so far as kpew perfectly well that arteries contain to perceive that the kidneys separate out blood; and this is a matter of some im. the urine which, as he correctly says, then portance, because it has been the habit of flows into the bladder. His chapters on historians of physiology to affirm that all the digestive tract display a surprisingly the ancients supposed arteries to contain extensive and detailed investigation of the air. In speaking of the cavities of the alimentary system of many animals; and heart, he appears to have fallen into the the observations made are for the most unaccountably foolish blunder of saying part accurate. In particular, his descripthat no animal has more than three, and tions of the teeth, esophagus, epiglottis, that some animals have as few as one. and the mechanism of deglutition, display But, although this apparent error has been so surprising an amount of careful and harped upon by his critics, it is clearly no detailed observation throughout the verteerror at all. Professor Huxley bas shown brated series, that they read much like a that what Aristotle here did was to regard modern treatise upon these branches of the right auricle as a venous sinus, or as comparative anatomy. The same remark a part of the great vein, and not of the applies to his disquisition on horns. heart. The only mistake of any impor- Where inaccurate, his mistakes here are tance that he made in all his researches mostly due to his ignorance of exotic upon the anatomy of the heart and blood- forms. vessels, was in supposing that the number Adipose tissue he correctly viewed as of cavities of the heart is in some measure excess of nutritive matter extracted from determined by the size of the animal. the blood; and he noted that fatness is Here he undoubtedly lays himself open to inimical to propagation. Marrow he likethe charge of basing a general and erro- wise correctly regarded as baving to do neous statement on a preconceived idea, with the nutrition of bones; and observed without taking the trouble to test it by that in the embryo it consists of a vascular observation. But we may forgive him pulp. tbis little exhibition of negligence when That Aristotle should have had no glimwe find that it was committed.by the same mering notion either of the nervous sysobserver, who correctly informs us that tem, or of its functions, is, of course, not the heart of the chick is first observable surprising ; but to me it is surprising that as a pulsating point on the third day of so acute an observer should have failed to incubation, or who graphically tells us perceive the physiological meaning of that just as irrigating trenches in gardens muscles. Although he knew that they are are constructed to distribute water from attached to bones, that they occur in one single source through numerous chan-greatest bulk where most strength of pels, which divide and subdivide so as to movement is required - such as in the convey it to all parts, and thus to nourish arms and legs of man, the breasts of birds, the garden plants which grow at the ex- and so forth, - and although he must pense of the water; so the blood-vessels have observed that the muscles swell and start from the heart in a ramifying system, harden when the limbs move, yet it never in order to conduct the nutritive fluid to occurred to him to connect muscles with all regions of the body. Lastly, Aristotle the phenomena of movement.
He reexperimented on coagulation of the blood, garded them only as padding, having also and obtained accurate results as to the in some way to do with the phenomena of comparative rates with which the process sensation. Thus we appear to have one takes place in the blood of different ani- of those curious instances of feeble ob. mals. He also correctly described the servation with which, every now and then, phenomenon as due to the formation of a he takes us by surprise. To give parenmeshwork of fibres; but he appears to thetically a still more strange example of have erroneously supposed that these what I mean, one would think that there fibres exist in the blood before it is drawn is nothing in the economy of a star-fish or from the body.
an echinus more conspicuous, or more So much, then, for his views upon the calculated to arrest attention, than the heart, the blood, and the blood-vessels. ambulacral system of tube feet. Yet ArisHe was less fortunate in his teaching about totle, while describing many other parts the bladder, kidneys, liver, spleen, and so of those animals, is quite silent about this forth, because he had no sufficient physio- ambulacral system. I think this fact can logical data to go upon. Still, one would only be explained by supposing that he think he might have avoided the error of confined his observations to dead speci.
mens; but, as he was not an inland natu- | as if it were a living animal, and as if it ralist, even this explanation does not were the beginning of all animals that acquit him of a charge of negligence, have blood.” which, when contrasted with his custom- Turning now for a moment to Aristotle's ary diligence, appears to me extraordinary. still more detailed discoveries in compar.
His ignorance of the nervous system ative anatomy and physiology, his most led him to a variety of speculative errors. remarkable researches are, I think, those In particular, he was induced to regard on the cetacea, crustacea, and cepha. the heart as the seat of mind, and the lopoda. Here the amount of minute and brain as a bloodless organ, whose function accurate observation which he displayed it was to cool the heart, which he supposed is truly astonishing; and in some cases to be not only the organ of mind, but also his statements on important matters of an apparatus for cooking the blood, and by fact have only been verified in our own it the food. The respiratory system was century - such, for instance, as the peculalso conceived by him as a supplementary iar mode of propagation which has now apparatus for the purpose of keeping the been re-discovered in some of the cephabody cool - a curious illustration of early lopoda.* He also knew the anomalous philosophical thought arriving at a conclu- fact that in these animals the vitellus is sion which, to use his own terminology, joined to the mouth of the embryo; that was directly opposed to the truth. Never- in certain species of cartilaginous fish the theless, the reasoning which landed him embryo is attached to its parent by the in this erroneous conclusion was not only intervention of a placenta-like structure; perfectly sound, but also based upon a and, in short, detailed so many anatomical large induction from facts, the observation discoveries both as regards the vertebrata of which is highly creditable. The reason and invertebrata, that a separate article why he supposed the office of respiration would be required to make them intellito be that of cooling the body was because gible to a general reader. In this connecnearly all animals which respire by means tion, therefore, I will only again insist of lungs exhibit a high temperature, and, upon the enormous difference between imagining that temperature or “vital Aristotle and the great majority of his heat " was a property of the living soul, illustrious countrymen in respect of methhis inference was inevitable that the func-od. Unless it can be shown that an antion of the lungs was that of keeping down cient writer has been led to anticipate the the temperature of warm-blooded animals. results of modern discovery by the legitiHere, then, his error was due to deficiency mate use of inductive methods, he de. of information, and the same has to be serves no more credit for his guesses said of the great majority of his other when they happen to have been right than
For instance, with regard to the he does when they happen to have been one already mentioned about the heart wrong. This, however, is a consideration being the seat of mind, this is usually said which we are apt to neglect. When we by commentators to have been due merely find that an old philosopher has made a to the accident of the heart occupying a statement which science has afterwards central position. And no doubt such was shown to be true, we are apt to regard the partly his reason, for he considered that fact as proof of remarkable scientific inposition the noblest, and repeatedly argues sight, whereas, when we investigate the that on this account it must be the seat of reasonings which led him to propound the mind. But over and above this mystical, statement, we usually find that they are not to say childish reason, I think he must of a puerile nature, and only happened to have had another. For seeing that the hit the truth, as it were, by accident. error is a very general one in early philo- Among a number of guesses made at ransophical thought — we find it running dom and in ignorance, a certain percentage through the Psalms, and it is still conven. may well prove right; but under these tionally retained by all poetic writers — 1 circumstances the man who happens to think we must look for some more evident make a correct guess deserves no more reason than that of mere position to credit than he who bappens to have made account for it. And this reason I take an
Indeed, he may de. to be the perceptible influence on the serve even less credit. For instance, heart-beat which is caused by emotions of when the Pythagoreans, on a basis of various kinds. Furthermore, Aristotle various mystical and erroneous speculaexpressly assigns the following as another tions, propounded a kind of dim adumbraof his reasons : “In the embryo the heart
Lewes, however, denies that the evidence is sufappears in motion before all other parts, I cient to show that Aristotle knew this.
tion of the heliocentric theory, far from drawing the boundary-lines between plants deserving any credit for superior sagacity and animals. For,' while he correctly at the hands of modern science, they merit guessed, from erroneous observation, that condemnation for their extravagant theo- sponges should be classified as animals, rizing and unguarded belief. In their he decided in favor of placing the hydroid time, whatever evidence there was lay on polyps among the plants; and he appears the side of the then prevalent view that to have classified certain testaceous molthe sun moves round the earth. There- luscs in the same category. Man, of fore, when, without adducing any counter- course, he places at the head of the animal evidence of a scientific kind, they affirmed kingdom; and shows a profound penetrathat the earth moved round the sun, they tion in drawing the true psychological were merely displaying the spirit of what distinction between him and the lower the Yankees call "pure cussedness.” animals, namely, that animals only know That is to say, they were shutting their particular truths, never generalize, or form eyes to the only evidence which was abstract ideas. available, and showing their own obstinacy His conception of life was more in acby propounding a directly opposite view. cordance with that of modern science than The sound maxim in science is, that he that of any of the other conceptions which discovers who proves; and this is a maxim have been formed of it either in ancient which many classical scholars would do times or the Middle Ages. For he seems well to remember when writing about the clearly to have perceived the error of rescientific speculations of the early Greeks. garding the “Vital Principle” otherwise
Now I have made these remarks in than as an abstraction of our own making. order again to emphasize the almost unique Life and mind in his view were abstracposition which Aristotle holds among his tions pertaining to organisms, just in the contemporaries in this respect. Instead same way as weight and heat are abstracof giving his fancy free rein upon " the tions pertaining to inanimate objects. For high priori road," he patiently plods the convenience of expression, or
even for way of detailed research ; and when he purposes of research, it may be desirable proceeds to generalize, he does so as far to speak of weight and heat as indepen. as possible upon the basis of his inductive dent entities; but we know that they canexperience.
not exist apart from material objects —
that they are what we term qualities, and Coming now to his generalizations, it not themselves objects. And so with life
a true philosopbical insight which and mind; they are regarded by Aristotle enabled Aristotle to perceive in organic as qualities — or, as we should now say, nature an ascending complexity of organi- functions -of organisms. And here we zation from the vegetable kingdom up to must remember that the whole course of
Instead of the three kingdoms of previous speculation on such matters pronature, which were afterwards formulated ceeded on the assumption that the vital by the alchemists, and which in general principle was an independent entity superparlance we still continue to preserve, added to organisms, serving to animate namely, the mineral, vegetable, and animal them as long as it was united to them, leav. - instead of these three kingdoms, Aris. ing them to death and decay as soon as it totle adopted the much more philosophical was withdrawn from them; and even then classification of nature into two divisions, being itself able to survive as disemthe organic and the inorganic, or the living bodied spirit, enjoying its conscious exand the not-living. Nevertheless, he fell istence apart from all material conditions. into the error — which was, indeed, al. Thus it was that the creations of early most unavoidable in his time - of sup- thought peopled the world with ghosts posing that there is a natural and a daily and spirits more numerously than nature passage of the one into the other. How- had supplied it with living organisms. ever, he again shows his philosophical Now Aristotle boldly broke away from insight where he points out the leading this fundamental assumption of the vital distinctions between plants and animals, principle as an independent and superthe former manifesting life in the phe added entity. In the phenomena of life
of nutrition alone, including and mind he saw merely the functions of germination, growth, repair, and repro- organism; he assigned to them both a duction ; while the latter, besides these, physical basis, and clearly perceived that exhibit also the phenomena of sensation, for any fruitful study of either we must volition, and spontaneous movement. He have recourse to the methods of physiol. was not so fortunate in his attempts at logy.