§ 67. I have insisted on these general truths with perhaps needless iteration, to prepare the reader for more fully recognizing a corollary that is practically ignored. Abundant and clear as is the evidence, and forced though it is daily on every one's attention, the conclusions respecting life and conduct which should be drawn, are not drawn, and so much at variance are these conclusions with current beliefs, that enunciation of them causes a stare of incredulity. Pervaded as all past thinking has been, and as most present thinking is, by the assumption that the nature of every creature has been specially created for it, and that human nature, also specially created, is, like other natures, fixed--pervaded too as this thinking has been, and is, by the allied assumption that the agreeableness of certain actions depends on their essential qualities, while other actions are by their essential qualities made disagreeable; it is difficult to obtain a hearing for the doctrine that the kinds of action which are now pleasurable will, under conditions requiring the change, cease to be pleasurable, while other kinds of action will become pleasurable. Even those who accept the doctrine of Evolution mostly hear with scepticism, or at best with nominal faith, the inferences to be drawn from it respecting the humanity of the future. And yet as shown in myriads of instances indicated by the few above given, those natural processes which have produced multitudinous forms of structure adapted to multitudinous forms of activity, have simultaneously made these forms of activity pleasurable. And the inevitable implication is that within the limits imposed by physical laws, there will be evolved, in adaptation to any new sets of conditions that may be established, appropriate structures of which the functions will yield their respective gratifications.