Here, then, is an accumulation of proofs. Living aggregates are distinguishedby the associated facts, that during integration they undergo remarkablesecondary changes which other aggregates do not undergo to anything likethe same extent; and that they contain (bulks being supposed equal) immenselygreater quantities of motion, locked up in various ways. §105. The last chapter closed with the remark that while Evolutionis always an integration of Matter and dissipation of Motion, it is in mostcases much more. And this chapter opened by specifying the conditions underwhich Evolution is integrative only, or remains simple, and the conditionsunder which it is something further than integrative, or becomes compound.
In illustrating this contrast between simple and compound Evolution, andin explaining how the contrast arises, a vague idea of Evolution in generalhas been conveyed. Unavoidably, we have to some extent forestalled the fulldiscussion of Evolution about to be commenced.
There is nothing in this to regret. A preliminary conception, indefinitebut comprehensive, is needful as an introduction to a definite conception.
A complex idea is not communicable directly, by giving one after anotherits component parts in their finished forms; since if no outline pre-existsin the mind of the recipient these component parts will not be rightly combined.
Much labour has to be gone through which would have been saved had a generalnotion, however cloudy, been conveyed before the distinct and detailed delineationwas commenced.
That which the reader has incidentally gathered respecting the natureof Evolution from the foregoing sections, he may thus advantageously useas a rude sketch. He will bear in mind that the total history of every sensibleexistence is included in its Evolution and Dissolution; which last processwe leave for the present out of consideration. He will not forget that whateveraspect of it we are for the moment considering, Evolution is always to beregarded as an integration of Matter and dissipation of Motion, which maybe, and usually is, accompanied by other transformations of Matter and Motion.
And he will everywhere expect to find that the primary re-distribution endsin forming aggregates which are simple where it is rapid, but which becomecompound in proportion as its slowness allows the effects of secondary re-distributionsto accumulate. §106. There is much difficulty in tracing out transformations sovast, so varied, and so intricate as those now to be entered upon. Besideshaving to deal with concrete phenomena of all orders, we have to deal witheach group of phenomena under several aspects, no one of which can be fullyunderstood apart from the rest and no one of which can be studied simultaneouslywith the rest. Already we have seen that during Evolution two great classesof changes are going on together; and we shall presently see that the secondof these great classes is re-divisible. Entangled with one another as allthese changes are, explanation of any one class or order involves director indirect reference to others not yet explained. We can do no more thanmake the best compromise.
It will be most convenient to devote the next chapter to a detailed accountof Evolution under its primary aspect; tacitly recognizing its secondaryaspects only so far as the exposition necessitates.
The succeeding two chapters, occupied exclusively with secondary re-distributions,will make no reference to the primary re-distribution beyond that which isunavoidable: each being also limited to one particular trait of the secondaryre-distributions.
In a further chapter will be treated a third, and still more distinct,character of the secondary re-distributions.
