The repugnance of certain psychologists to admit indifferent states arises from the fact that this thesis appears to them to introduce discontinuity into the affective life. The mobile and incessantly alternating series of pleasurable or painful modifications would, in that case, have moments of interruption, gaps, and vacant spaces. I yield to no one in asserting the continuity of the affective life; but it must be sought elsewhere. It is in the appetites, the tendencies—conscious or unconscious—the desires and aversions, which, for their part, are always at work, permanent and indestructible. Here, again, we find the mistake of considering pleasure and pain, which are only symptoms, as essential and fundamental elements. I find it strange, moreover, that, in a subject so much studied and discussed, no one should have contributed an observation which seems to me of some importance. Each author supposes the formula adopted by himself to be applicable to all men. This is to state the question in a philosophical, not in a psychological form—_i.e._, without taking into account individual variations of temperament and character, an element by no means to be neglected. It is to suppose, without the least proof, that all cases are reducible to unity. On the contrary, there are presumptions that the solution adopted, whatever it is, may be true for some men and false for others. A nervous, excitable temperament, in a perpetual state of vibration, constantly kept on the alert by the workings of passion or thought, may, by its very constitution, leave no moment accessible to an intermission of the incessantly renewed states of pain and pleasure. A lymphatic temperament, on the other hand, a cold disposition, a limited intelligence, poor in ideas, constitute a soil perfectly suited to the frequent appearance and long continuance of indifferent states.[58] Footnote 58: