Whence does this environmental pressure obtain the power which enables it to exercise in the child’s mind the regal functions of instinct? Clearly it can do so only if the mind possesses a specific sensitiveness to external opinion and the capacity to confer on its precepts the sanction of instinctive force. In the two earlier essays of this book I attempted to show that the essential specific characteristic of the mind of the gregarious animal is this very capacity to confer upon herd opinion the psychical energy of instinct. It is this sensitiveness, then, which lays the child’s mind open to the influence of his environment and endows for him the mental attitude of that environment with all the sanction of instinct. Thus do the repressing forces {83} become actually constituent in the child’s personality, and as much a part of his being as the egoistic desires with which they are now able to contend on equal terms. The specific sensitiveness of the gregarious mind seems, then, to be a necessary condition for the establishment of true mental conflict, and a character which must be taken into account if we are to develop a complete theory of the evolution of the individual mind. Assuming the validity of the proposition that there are two primary factors in the development of the mind in each individual—the egoistic impulses of the child and his specific sensitiveness to environing influences—it may well be asked why it is that the product, the “normal” adult mind, is so uniform in its characters. It is true that this uniformity may very easily be exaggerated, for in a very considerable number of cases gross “abnormalities” are the result of the process of development, but, as I pointed out in an earlier essay, the result on the whole is to produce two broadly distinguishable types of mind—the unstable and the stable—the latter on account of its numerical superiority being also dignified as normal. A considerable uniformity in the final products must therefore be accepted. If, however, environmental influences are an essential factor in the production of this result, there seems no little difficulty in accounting for the uniformity seeing that environments vary so much from class to class, nation to nation, and race to race. Where, we may ask, is the constant in the environmental factors which the uniformity of the outcome leads us to expect? Assuming with Freud that of the egoistic impulses of the child, the sexual alone seriously counts in the formation of character, can it be shown that the influences which surround the child are uniform {84} in their general direction against this? At first sight it would seem certainly not. Even in the same country the variations in taste, reticence, modesty, and morality towards matters of sex interest vary greatly from class to class, and presumably are accompanied by corresponding variations in the type of influence exercised by the environment of the child.