Of the two personalities—the subconscious and the normal—the former alone is suggestible; the successful operation of suggestion implies the recurrence, however transient, of a disaggregation of personality, and the emergence of the subwaking self as the controlling mind (pp. 89 and 90). It is this suggestibility of the subwaking self which enables man to be a social animal. “Suggestibility is the cement of the herd, the very soul of the primitive social group. . . . Man is a social animal, no doubt, but he is social because he is suggestible. Suggestibility, however, requires disaggregation of consciousness, hence society presupposes a cleavage of the mind. Society and mental epidemics are intimately related; for the social gregarious self is the suggestible subconscious self” (p. 310).
Judged from our present standpoint, the most valuable feature of Sidis’s book is that it calls attention to the undoubtedly intimate relation between gregariousness and suggestibility. The mechanism, however, by which he supposes suggestibility to come into action is more open to criticism. The conception of a permanent subconscious self is one to which it is doubtful whether the evidence compels assent.11 The essential difference, however, which Sidis’s views present from those to be developed below, lies in his regarding suggestibility as being something which is liable to intrude upon the normal mind as the result of a disaggregation of consciousness, instead of as a necessary quality of every normal mind, continually present, and an inalienable accompaniment of human thought. A careful reading of his book gives a very clear impression that he looks upon suggestibility as a {28} disreputable and disastrous legacy of the brute and the savage, undesirable in civilized life, opposed to the satisfactory development of the normal individuality, and certainly in no way associated at its origin with a quality so valuable as altruism. Moreover, one gets the impression that he regards suggestibility as being manifested chiefly, if not solely, in crowds, in panics, revivals, and in conditions generally in which the element of close association is well marked.