Indeed, to say that we ought to promote the end of evolution, and that this end is annihilation, is inconsistent with the postulate always implied by the ethics of evolution--the postulate that conduct should promote evolution because life is desirable,[220] and increase of life comes with the progress of evolution. Nor is it of any assistance to reply to this by saying that the dissolution in which evolution ends may be only the prelude to another process of evolution in which life will gradually progress till it again reaches equilibrium. For, in the first place, this is only a problematical suggestion--is not, to speak in Mr Spencer's language, "demonstrable _à priori_ by deduction from the persistence of force," as the tendency of present evolution to equilibrium is held to be; and secondly, the new process, if it were to come about, would have to begin again the slow ascent from the lowest rung of the ladder of existence: so that, in aiding evolution towards the goal of equilibrium, we should be only guiding it to the old starting-point which has now, after many a painful struggle, been left far behind. * * * * * [Sidenote: (_c_) Insufficiency of adaptation as evolutionist end:] [Sidenote: tendency to variation in all organisms,] But further, it would seem that the theory of evolution itself is not fairly represented by a view which emphasises the fact of adaptation to environment to the exclusion of that of variation. The latter is as necessary to progressive development as the former. Adaptation to environment might seem to be most nearly complete when organism and environment were both so simple as to be hardly separate. The polype, which is scarcely different from the sea-water it inhabits, might seem by correspondence with its medium to be near the maximum of adaptation, though at the very beginning of life. It may be solely because the environment is subject to numerous changes that the organism of simple structure cannot maintain life. But it is only through its own inherent power of variation that progress in organic life is possible. Perfect correspondence with the environment was not reached by simple organisms, not only on account of the want of uniformity in their surroundings, but also because there is in every organism a tendency to variation through which the modifications are produced which natural selection takes hold of. Did organisms not tend to vary in function and structure, no progressive modification would be possible. Those fittest to live would be selected once for all, and all but those adapted to the environment weeded out.