Again, we have seen in the preceding chapter that the impressionability of the nerves and brain in the degenerate subject is blunted. Hence he only perceives strong impressions, and it is only these which excite his cerebral centres to that intellectual and motor activity which produces in them feelings of pleasure. Now, disagreeable impressions are naturally stronger than agreeable or indifferent impressions, for if they were not stronger we should not feel them as painful, and they would not induce the organism to make efforts to defend itself. To procure, then, the feelings of pleasure which are linked with the activity of the cerebral centres, to satisfy the need of functioning which is peculiar to the cerebral centres as to all the other organs, the degenerate person seeks impressions which are strong enough to excite to activity his obtuse and inert centres. But such impressions are precisely those which the healthy man feels as painful or repugnant. Thus, the aberrations or perversions of the degenerate find explanation. They have a longing for strong impressions, because these only can put their brains into activity, and this desired effect on their centres is only exercised by impressions that sane beings dread because of their violence, _i.e._, painful, repugnant and revolting impressions. To say that every human being has secretly a certain predilection for the evil and the abominable is absurd: the only little spark of truth contained in this foolish assertion is, that even the normal human being becomes obtuse when fatigued, or exhausted by illness; _i.e._, he falls into the state which, in the degenerate, is chronic. Then he presents naturally the same phenomena as we have attested in the case of the latter, although in a much lower degree. He may find pleasure, then, in crime and ugliness, and in the former rather than in the latter; for crimes are social injuries, while uglinesses are the visible form of forces unfavourable to the individual; but social instincts are feebler than the instincts of self-preservation. Consequently they are sooner put to sleep, and for this reason the repulsion against crime disappears more quickly than that against ugliness. In any case, this state is also an aberration in the normal being, but imputable to fatigue, and in him is not chronic, as in the degenerate, nor does it amount to the hidden fundamental character of his being, as the sophists who calumniate him pretend.