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and in apportioning their functions to the different organs he is entirely dominated by this fundamental error. It was a common notion among the Grecks, suggested by sufficiently obvious considerations, that the brain is the seat of the psychic activities. These, however, Aristotle transports to the heart, which, in his system, not only propels the blood through the body, but is also the source of heat, the common centre where the different special sensations meet to be compared, and the organ of imagination and of passion. The sole function of the brain is to cool down the blood-a

purpose which the lungs also subserve. Some persons believe that air is a kind of food, and is inhaled in order to feed the internal fire; but their theory would involve the absurd consequence that all animals breathe, for all have some heat. Anaxagoras and Diogenes did, indeed, make that assertion, and the latter even went so far as to say that fish breathe with their gills, absorbing the air held in solution by the water passed through them-a misapprehension, says Aristotle, which arose from not having studied the final cause of respiration. His physiological theory of generation is equally unfortunate. In accordance with his metaphysical system, hereafter to be explained, he distinguishes two elements in the reproductive process, of which one, that contributed by the male, is exclusively formative; and the other, that contributed by the female, exclusively material. The prevalent opinion was evidently, what we know now to be true, that each parent has both a formative and a material share in the composition of the embryo. Again, Aristotle, strangely enough, regards the generative element in both sexes as an unappropriated portion of the animal's nutriment, the last and most refined product of digestion, and therefore not a portion of the parental system at all; while other biologists, anticipating Mr. Darwin's theory of pangenesis in a very wonderful manner, taught that the semen is a con

1 De Respir., i. and ii.

flux of molecules derived from every part of the body, and thus strove to account for the hereditary transmission of individual peculiarities to offspring.'

All these, however, are mere questions of detail. It is on a subject of the profoundest philosophical importance that Aristotle differs most consciously, most radically, and most fatally from his predecessors. They were evolutionists, and he was a stationarist. They were mechanicists, and he was a teleologist. They were uniformitarians, and he was a dualist. It is true that, as we mentioned at the beginning of this chapter, Mr. Edwin Wallace makes him 'recognise the genesis of things by evolution and development,' but the meaning of this phrase requires to be cleared up. In one sense it is, of course, almost an identical proposition. The genesis of things must be by genesis of some kind or other. The great question is, what things have been evolved, and how have they been evolved? Modern science tells us, that not only have all particular aggregates of matter and motion now existing come into being within a finite period of time, but also that the specific types under which we arrange those aggregates have equally been generated; and that their characteristics, whether structural or functional, can only be understood by tracing out their origin and history. And it further teaches us that the properties of every aggregate result from the properties of its ultimate elements, which, within the limits of our experience, remain absolutely unchanged. Now, Aristotle taught very nearly the contrary of all this. He believed that the cosmos, as we now know it, had existed, and would continue to exist, unchanged through all eternity. The sun, moon, planets, and stars, together with the orbs containing them, are composed of an absolutely ungenerable, incorruptible substance. The earth, a cold, heavy, solid sphere, though liable to superficial changes, has always occupied its present position in the centre of the universe. De Gen. An., I., xvii.

The specific forms of animal life-except a few which are produced spontaneously-have, in like manner, been preserved unaltered through an infinite series of generations. Man shares the common lot. There is no continuous progress of civilisation. Every invention and discovery has been made and lost an infinite number of times. Our philosopher could not, of course, deny that individual living things come into existence and gradually grow to maturity; but he insists that their formation is teleologically determined by the parental type which they are striving to realise. He asks whether we should study a thing by examining how it grows, or by examining its completed form: and Mr. Wallace quotes the question without quoting the answer. Aristotle tells us that the genetic method was followed by his predecessors, but that the other method is his. And he goes on to censure Empedocles for saying that many things in the animal body are due simply to mechanical causation; for example, the segmented structure of the backbone, which that philosopher attributes to continued doubling and twisting the very same explanation, we believe, that would be given of it by a modern evolutionist. Finally, Aristotle assumes the only sort of transformation which we deny, and which Democritus equally denied that is to say, the transformation of the ultimate elements into one another by the oscillation of an indeterminate matter between opposite qualities.

Outlines, p. 30.

? There is a passage in the Politics (I., ii., sub. in.) in which Aristotle distinctly inculcates the method of studying things by observing how they are first produced, and how they grow; but this is quite inconsistent with the more deliberate opinion referred to in the text (De Purt. An., I., i., p. 640, a, 10). Perhaps, in writing the first book of the Politics he was more immediately under the influence of Plato, who preferred the old genetic method in practice, though not in theory.

VI.

The truth is that while our philosopher had one of the most powerful intellects ever possessed by any man, it was an intellect strictly limited to the surface of things. He was utterly incapable of divining the hidden forces by which inorganic nature and life and human society are moved. He had neither the genius which can reconstruct the past, nor the genius which partly moulds, partly foretells the future. But wherever he has to observe or to report, to enumerate or to analyse, to describe or to define, to classify or to compare ; and whatever be the subject, a mollusc or a mammal, a mouse or an elephant; the structure and habits of wild animals; the different stages in the development of an embryo bird; the variations of a single organ or function through the entire zoological series; the hierarchy of intellectual faculties; the laws of mental association; the specific types of virtuous character; the relation of equity to law; the relation of reason to impulse; the ideals of friendship; the different members of a household; the different orders in a State; the possible variations of political constitutions, or within the same constitution; the elements of dramatic or epic poetry; the modes of predication; the principles of definition, classification, judgment, and reasoning; the different systems of philosophy; all varieties of passion, all motives to action, all sources of conviction;—there we find an enormous accumulation of knowledge, an unwearied patience of research, a sweep of comprehension, a subtlety of discrimination, an accuracy of statement, an impartiality of decision, and an all-absorbing enthusiasm for science, which, if they do not raise him to the supreme level of creative genius, entitle him to rank a very little way below it.

It was natural that one who ranged with such consummate mastery over the whole world of apparent reality, should believe in no other reality; that for him truth should only

mean the systematisation of sense and language, of opinion, and of thought. The visible order of nature was present to his imagination in such precise determination and fulness of detail that it resisted any attempt he might have made to conceive it under a different form. Each of his conclusions was supported by analogies from every other department of enquiry, because he carried the peculiar limitations of his thinking faculty with him wherever he turned, and unconsciously accommodated every subject to the framework which they imposed. The clearness of his ideas necessitated the use of sharply-drawn distinctions, which prevented the free play of generalisation and fruitful interchange of principles between the different sciences. And we shall have occasion to show hereafter, that, when he attempted to combine rival theories, it was done by placing them in juxtaposition rather than by mutual interpenetration. Again, with his vivid perceptions, it was impossible for him to believe in the justification of any method claiming to supersede, or even to supplement, their authority. Hence he was hardly less opposed to the atomism of Democritus than to the scepticism of Protagoras or the idealism of Plato. Hence, also, his dislike for all explanations which assumed that there were hidden processes at work below the surface of things, even taking surface in its most literal sense. Thus, in discussing the question why the sea is salt, he will not accept the theory that rivers dissolve out the salt from the strata through which they pass, and carry it down to the sea, because river-water tastes fresh; and propounds in its stead the utterly false hypothesis of a dry saline evaporation from the earth's surface, which he supposes to be swept seawards by the wind.' Even in his own especial province of natural history the same tendency leads him astray. He asserts that the spider throws off its web from the surface of its body like a skin, instead of evolving it from within, as Democritus had taught." The same thinker had 2 Hist. An., IX., xxxix., sub fin.

Meteor., II., iii., 357, a, 15 ff.

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