[Sidenote: (α) Incompleteness of the evolutionist argument.] It is necessary for the evolutionist who holds that the development of life does not tend to increased pleasure, to meet the argument already adduced[165] to show their correspondence. Nor does that argument seem to be altogether beyond criticism. To compare progress or development with pleasure, we ought to know exactly what is meant by both terms. Yet it is impossible to have a clear notion of progress without an idea of the end to which it tends, and this has not yet been obtained. It is largely on account of the difficulty of obtaining such an idea that some evolutionists seem to have been driven to measure progress in terms of pleasure, just as, owing to the difficulty of estimating and summing up pleasures, some hedonists have been induced to measure them by the progress of evolution. What we have now to see is whether the correspondence assumed between progress and pleasure actually exists. And, to avoid the tautology of saying that progress is increase of life, we must judge of it simply by empirical observation of the nature of human activity and of the course of human affairs. Now the attempted identification of pleasurable and life-promoting activities rests on an incomplete account of the motives and results of action. For, in the first place, even admitting that pleasure and avoidance of pain are the only motives to action, the influence of natural selection has not prevented actions hurtful to life being sometimes accompanied by pleasant sensations. Its tendency to do so has been much more effective in the lower orders of animal life than in the higher. The latter, especially man, possess the power of representing ideal states in the imagination, and are thus able to avoid actions hurtful to life, although these actions are pleasant at the time. For the hurtful consequences of the action may be so vividly represented in idea as to outweigh the influence of the present pleasure which could be got from its enjoyment.[166]