Shall we say, then, that the end of human conduct is adaptation to environment? This seems to be the position taken up by some evolutionists. In the language of von Baer,[194] "the end of ends is always that the organic body be adapted to the conditions of the earth, its elements and means of nutriment;" and Mr Spencer holds "that all evil results from the non-adaptation of constitution to condition."[195] The hedonism which Mr Spencer definitely accepts as his ethical principle prevents him, indeed, from fully adopting the theory of human action which von Baer seems to regard as the result of the doctrine of evolution. Yet complete adaptation of constitution to condition is held by him to be characteristic of that perfect form of life to which evolution tends, and the laws of which are to be our guides in our present imperfect social condition. In working out his theory of ethics, he describes acts as "good or bad according as they are well or ill adjusted to ends," identifying the good with "the conduct furthering self-preservation," and the bad with "the conduct tending to self-destruction."[196] The notion of self-preservation thus introduced is naturally suggested as the end subserved by the activity of an organism being adjusted to surrounding conditions. Self-preservation, therefore, rather than adaptation to environment, will be regarded as the end, with which adaptation will be connected as the essential means. This notion of self-preservation has played a remarkable part in ethical and psychological discussion since the time of the Stoics. It withdraws attention from the relative and transient feeling of pleasure to the permanence of the living being. Thus, with the Stoics, the notion of self-preservation was accompanied by an ethics hostile to indulgence in pleasure; while, on the other hand, in Spinoza and in Hobbes, pleasure was recognised as the natural consequence of self-preserving acts--the former defining it as a transition from less to greater perfection, the latter as the sense of what helps the vital functions. The theory of evolution has, of course, not only its distinctive contribution to make to the connection between self-preservation and pleasure--a subject already referred to,--but also shows how an increasing harmony has been produced between acts which tend to self-preservation and those which tend to social-preservation. With Mr Spencer these two points are united. His doctrine that the "conduct which furthers race-maintenance evolves hand-in-hand with the conduct which furthers self-maintenance"[197] is preliminary to the establishment of the proposition that the highest life is one in which egoistic and "altruistic" acts harmonise with one another and with external conditions: "the life called moral is one in which this moving equilibrium reaches completeness or approaches most nearly to completeness."[198] [Sidenote: Self-preservation and social-preservation.]