be a certain amount of weariness and tedium which must be resisted and overcome, if we would bring our faculties into full play, and obtain the full enjoyment of our labour. And similarly in respect of passive emotional consciousness: if too much sameness of feeling results in languor, too much variety inevitably involves shallowness. The point where concentration ought to stop, and where dissipation begins, varies from man to man, and must, it would seem, be decided by the specific experience of individuals. There is, however, another and simpler way in which the maxim of ‘giving free development to one’s nature’ may be understood: _i.e._ in the sense of yielding to spontaneous impulses, instead of endeavouring to govern these by elaborate forecasts of consequences: a scientific justification for this course being found in the theory that spontaneous or instinctive impulses really represent the effects of previous experiences of pleasure and pain on the organism in which they appear, or its ancestors. On this ground, it has been maintained that in complicated problems of conduct, experience will “enable the constitution to estimate the respective amounts of pleasure and pain consequent upon each alternative,” where it is “impossible for the intellect” to do this: and “will further cause the organism instinctively to shun that course which produces on the whole most suffering.”[150] That there is an important element of truth in this contention I would not deny. But any broad conclusion that non-rational inclination is a better guide than reason to the individual’s happiness would be quite unwarranted by anything that we know or can plausibly conjecture respecting biological evolution. For--overlooking the effect of natural selection to foster impulses tending to the preservation of the race rather than the pleasure of the individual, and granting that every sentient organism tends to adapt itself to its environment, in such a manner as to acquire instincts of some value in guiding it to pleasure and away from pain--it by no means follows that in the human organism one particular kind of adaptation, that which proceeds by unconscious modification of instinct, is to be preferred to that other kind of adaptation which is brought about by conscious comparison and inference. It rather seems clear, that this proposition can only be justified by a comparison of the consequences of yielding to instinctive impulses with the consequences of controlling them by calculations of resulting pleasure and pain. But it will hardly be maintained that in the majority of clear instances where non-rational impulse conflicts with rational forecast, a subsequent calculation of consequences appears to justify the former; the assertion would be in too flagrant conflict with the common sense and common experience of mankind. Hence, however true it may be that in certain cases instinct is on the whole a safer guide than prudential calculation, it would