CH. II. their laws of growth, and their liability to injurious BOOK II. influences." 2 What we should gain, then, supposing the filiation just spoken of to have been established, would be this, that we should then be able to affix a somewhat different and more definite meaning to the terms first progenitor and prototype. These words would then mean, not any individuals or types of animal or vegetable organisms indefinitely, but those varieties of living protoplasm, which could be shown to be ultimate by the analytic branch of biology. And Natural History would attain its goal the more completely, not according to its success in referring all the separate varieties of known organisms to the smallest possible number of original progenitors or prototypes in the distant past, but in referring them to those varieties of living protoplasm, whatever their number, which might be shown to arise or to have arisen, at any epoch, in consequence of purely chemical, or chemical and physical, processes. In short the true terminus a quo of the real evolution of life, which is the terminus ad quem of natural history, since history as a knowing is always retrospective, would, on the supposition in question, have been fixed by biology, which, as above said, is the fundamental and analytical branch of the science. The doctrine omne virum e vivo in natural history carries with it the supposition, that the first appearance of life on our planet took place at some undetermined epoch or epochs, and under peculiar conditions which have never again occurred, and which it is not attempted to describe, except in 2 On the Origin of Species, Chap. XIV., p. 518, Third Edition, 1861. VOL. II. S § 5. Natural History. quite general terms. It carries with it this supposition because, as a doctrine of history, which assumes without attempting to account for the fact or the possibility of life, that is, for what would be commonly called its creation, or its nature and origination together, it as much excludes the generation of known living beings out of nothing, e nihilo, as it excludes their generation out of non-living matter. The purpose, then, of natural history is to trace back the generation of all known forms of life to the original organisms produced at those supposed epochs, in doing which the discovery of their relationships to one another is necessarily involved. It is here that the great conception of Darwin and Wallace, known as the law of natural selection in the struggle for existence, has proved of such extreme significance, by establishing, as for the first time it did, the reality of processes capable of connecting descendants belonging to wholly different species with a common progenitor or progenitors, by an unbroken series of changes, as minute as are to be met with in any province of Nature's operations. It may be noted, that Mr. Herbert Spencer's doctrine of the "instability of the homogeneous" supplies a theoretical foundation for the fact of incessant variability, which is the acknowledged pre-requisite for the law of natural selection. The importance of this result for the whole system of human thought can hardly be exaggerated. Living beings, it is true, are but one class of real existents out of many, and the existing science of biology is not, like chemistry and the other physical sciences, a science possibly co-extensive with the whole material world seen in one aspect, or in reference to one particular class of phenomena, but the science of one particular class of existents in all its aspects. Still it was just this particular province which presented the chief, if not the sole, remaining obstacle to unity in our conceptions of the Order of Nature. Now it was this obstacle which was surmounted for the first time by the establishment of the law of natural selection in the struggle for existence. The obstacle consisted, not in the real existence of natural species, but in the circumstance, that their existence appeared inexplicable save by the intervention of "final causes," or preconceived plans, as real determinants of the Course of Nature; that is to say, causes whose efficiency was wholly different in kind from that of material existents, and the mode of whose operation was not positively construable to thought Every natural species, in fact, seemed to owe its existence to an idea, or conceived type, existing as an idea or conception previously to the existence of the individuals of the species which realised it, and determining the individuals to be what they were, in order to realise it. Science was for ever relieved from this rivalry between the heterogeneous conceptions of final and efficient causation, or real conditioning, when once it was shown, that the natural species of living beings were explicable without the intervention of "final causes" or ideal types, and resulted as facts from the simply efficient operation of physical, chemical, and vital energies. From this it by no means follows, that natural selection in the struggle for existence, founded on BOOK II. § 5. Natural History. BOOK II. § 5. Natural History. § 6. the occurrence and transmission of spontaneous variations, is the only line or mode of real conditioning which Nature takes in producing the divergence of relatively permanent species. The true connection of this line of determination with the nature and analysis of living protoplasm is a question which the discovery of the law of natural selection opened and prepared, but by no means answered. Darwin's own hypothesis of Pangenesis is a proof of this; and this hypothesis is but the first of a number of others which have since been proposed, with the view of placing the laws of descent and heredity on a sound analytical footing, by connecting them with the composition and structure of living matter as discovered, or to be discovered, by biological analysis, both in the vegetable and animal kingdoms. But I am not proposing to enter here upon the consideration of any of these hypotheses. Important as they are, and of the deepest interest, they are questions for experts, and questions still sub judice. Nor would their settlement one way or the other, have any direct influence, so far as I can see, upon any of the philosophical problems which are the main subject of the present work, whether these belong to the theoretical and speculative, or to the practical and ethical, branch of philosophy. I therefore make my bow to them and pass on. § 6. The next and last of the positive sciences, Psychology Psychology, is selective with regard to the objects of biology, just as we have seen that biology is selective with regard to the objects of chemistry. It selects as its object those living organisms which display, and so far as they display, consciousness in BOOK II. § 6. the widest sense, I mean as including all kinds and degrees, from mere sentience upwards to the most complex manifestations of intelligence, emotion and, Psychology. volition. The object-matter of psychology is thus double, comprising existents of two different kinds, living matter and consciousness, in conjunction. It is not a purely physical science, though dealing with material organisms. Neither is it a science of pure consciousness, though dealing with consciousness. It is consciousness in relation with the organisms which display it, or the display of consciousness by organisms, that is its object-matter. It thus closes the series of the great departments of positive science, by bringing us back to the study of consciousness, with the nature of which, or with which as a knowing in relation to what it knows, philosophy begins, by a special route, namely, by the enquiry into the Order of Existence, or the Order of Real Conditioning, in which consciousness now appears as what was called above, in Book I., a real existent, and one having its existence proximately conditioned on that of living matter. My readers will have, perhaps, only too lively a sense of the dry analysis by which I endeavoured in that Book to establish the distinction between consciousness as a knowing and consciousness as an existent. It is not necessary to repeat it here. It is only in its existent character that Consciousness enters into the total object-matter of psychology. It is the psychologically subjective half of that object - matter. With the subjective aspect of consciousness taken by itself, that is, with consciousness objectified as a knowing |