Evolution

by F. B. Jevons

What is thus true of physiology and of those chemical combinations on which it is based, is true also of sociology and the psychological facts on which it is based. "When physiological elements are combined, the combination reveals properties which were not appreciable in the separate elements. The increasingly complex combination or association of organic elements may produce an entirely special set of phenomena.... Their combination exhibits something more than the mere sum of their separate properties. Thus, no knowledge of man as an individual would enable us to forecast all the institutions which result from the association of men and which can only manifest themselves in social life."[19]

It is clear, then, that the mechanical theory of evolution can only maintain itself by obliterating the distinction between mechanical juxtaposition and chemical combination. The obstacles which stand in the way of this obliteration, at the outset, are two. First, the behaviour of a chemical compound bears no resemblance to the behaviour of its constituents when separate. Next, the laws of the compound cannot be deduced or exhibited as consequences of the laws of the separate elements. To these two objections it may be replied, first, that though the compound bears no resemblance to its separate constituents, the character of every aggregate must be determined by that of its component parts; and, next, that with more knowledge we shall come to see the way in which the laws of the separate components generate the law of the whole. Perhaps, by way of illustration, we may employ an analogy. A number of bricks can be placed on one another to form a cube; a number of cannon balls will form a pyramidical pile. The aggregate of bricks resembles in shape the separate bricks; the aggregate of balls does not resemble a ball in shape. Yet the pyramidical shape of the pile of cannon balls is as certainly determined by the shape of the separate balls, as the cubical shape of the heap of bricks is determined by that of the separate bricks. Now, we do not know the geometrical structure of chemical atoms; but, on this analogy, it is reasonable to suppose that, if we did, we should see at once that the structure of a chemical compound is dependent on, though different from, that of its elements. So too in sociology, the aggregate, society, is not a human being, but the character of any given society is determined by the character of its individual members.

This last illustration, however, brings us to a fresh difficulty in the way of the mechanical theory. As is observed in the remarks quoted previously from Monsieur Bernard, the peculiar characteristic of those more intimate combinations which form the subject-matter of chemistry, physiology, and sociology is that in them the combining elements reveal properties which were not perceptible in them previous to their combination. It may be true that the character of these more intimate combinations is determined by the properties of their constituents, but it is by the properties which they reveal when in combination, not by those which are manifest in them when uncombined. Therein lies the difference between mechanical compounds and chemical combinations; and it is that difference which the mechanical theory does not account for. The more intimate, chemical, physiological, and sociological combinations take place in virtue of properties which require the combination to reveal them. In sociology it is not the juxtaposition of individual men, but their co-operation, which makes a society. In chemistry, the formation of chemical compounds implies the affinity of the elements.

It seems, then, that the mechanical theory contains half the truth, but not the whole truth. The half-truth which it insists on is that in both mechanical and chemical combinations there is juxtaposition of the constituent elements. The half of the truth which it overlooks is that when the elements are juxtaposed in one way they develop or manifest new qualities, when juxtaposed in the other way they do not. The mechanical theory asserts that the only factors in evolution are matter and the force which moves matter about: it takes into account the external factors, but leaves out the internal force or spontaneity in virtue of which things in a suitable environment develop new qualities. Doubtless the juxtaposition of the elements is a condition without which they would not manifest their new properties: the redistribution of matter and motion is a condition of evolution, but it does not constitute evolution. Rather, it is the continual revelation of these new qualities which constitutes evolution, chemical affinity and all its consequences in chemistry, spontaneous variation and all its consequences in the evolution of organic life.

From this point of view it becomes clear why the laws of a chemical compound neither are nor can be exhibited as consequences of or deductions from the laws of its separate constituents. The properties which the law of the compound describes are not the properties which the separate elements exhibit. The living matter of biology, the active atoms of chemistry, are not products of the lifeless, inert matter of mechanics; but are different and higher revelations of the same power which is manifested in different degrees in all. It is this progressive manifestation, and not the mere drifting about of bits of matter, which constitutes evolution. The redistribution of matter and motion may be a concomitant of evolution, but it is not evolution. "The continuous adjustment of internal relations to external relations," which Mr. Herbert Spencer[20] offers as a definition of life, may be a condition of the maintenance of an organism; but life is and means to each one of us, and to the humblest thing that breathes, much more than that. Mr. Spencer's definition of life leaves, for instance, consciousness out, as of no account in life, and would be equally applicable to many automatic, self-adjusting machines. The definition constitutes an admission that life and consciousness cannot be exhibited as a consequence of the redistribution of matter and motion. They appear at a certain (or uncertain) point in the process of redistribution, and they have as concomitants certain further redistributions; but they are neither the consequence of nor are they identical with that redistribution; nor can their laws be reduced to mere cases of the laws of matter and motion.

The doctrine that evolution consists in nothing but movements in space, amounts to the assertion that we know nothing about things and men except that they move. In point of fact, we know a good deal more. We know that men think, and that the movement of thought is not a movement in space. We know that the vibrations of the ether are movements in space and that they are also something more: they are known to us also as sights, sounds, etc. No explanation or concise statement of the process of evolution can be satisfactory, or even scientific, which begins by denying the relevance and even the reality of the most important part of our knowledge. If the "first principles" of evolution are to be scientific, they must be inductions drawn from observation and based on some similarity in the phenomena observed, in which case, and in which case alone, they will apply to both classes of phenomena, mental and material. If any "principle" is true of one class alone, it is shown thereby not to be a "first principle": it is not universally applicable.

This raises the question whether there can be any first principles in this sense, whether mind and matter are, to some extent, subject to the same laws; or whether the resemblances which are sometimes drawn are not merely metaphors more or less expanded. Thus we speak of "weighty" objections; but will anyone maintain that ideas are subject to, or exemplify, the law of gravitation? We speak of ideas as "coherent" or "incoherent"; does anyone suppose that they stick together in the same way and from the same causes as material objects cohere?

Mr. Herbert Spencer has written a chapter[21] under the title "Society is an Organism," in which he points out many resemblances between society and an organism. But Mr. Spencer himself "distinctly asserts"[22] that the resemblances imply nothing more than that in both society and organisms there is "a mutual dependence of parts." That is to say, sociology does not herein "exemplify" some of the laws of biology, but sociology and biology both exemplify certain laws which hold good wherever there is a mutual dependence of parts.

Again, Mr. Spencer says[23] that "evolution is definable as a change from an incoherent homogeneity to a coherent heterogeneity, accompanying the dissipation of motion and integration of matter"; and, having shown how and why the homogeneous and the incoherent in the domain of physics tend to become coherent and heterogeneous, he proceeds to show that there is a similar process in the evolution of knowledge, and to say "these mental changes exemplify a law of physical transformations that are wrought by physical forces."[24] Now it doubtless is a fact that with intellectual development there goes a more accurate discrimination of differences at first unnoticed, a readier perception of resemblances at first undetected, a consequent segregation and classification of ideas, and a recognition of heterogeneity where homogeneity was at the first glance supposed to prevail. Doubtless, too, as a result of this process, there is greater coherency in our ideas. But is all this anything more than expanded metaphor? If it is something more, how can these mental changes "exemplify" a law of physics when ideas neither stick physically to each other nor gravitate to one another like the particles of the original, homogeneous, nebular mass? If mental and material phenomena can to some extent obey the same laws, and these laws are scientific inductions, there must be some resemblance between the phenomena.