The gratification may prove to be physically painful in itself. This seems to promise certain elements of mental conflict in balancing the pleasure of the gratification against the remembered pain it involves. We are assuming that the pain is the immediate consequence of the act, as when, for example, a child makes the immemorial scientific discovery that fire burns fingers. Such a direct experience without the interposition of a second person or the pointing of a moral does not in fact involve any real mental conflict. The source of the pain is external, its only emotional quality is that of its simple unpleasantness, and this cannot, as it were, enter into the child’s mind and divide it against itself. True conflict, the conflict which moulds and deforms, must be actually within the mind—must be endopsychic to use a term invented by Freud, though not used by him in this exact application. In order that a desire may set up conflict it must be thwarted, not by a plain impossibility or by a mere physical pain, but by another impulse within the mind antagonizing it. It seems clear that the counter-impulse to be strong enough to contend with an impulse having in it the energy of the sex instinct must itself derive its force from some potent instinctive mechanism. We cannot suppose that the immense power of the sex impulse can be {82} controlled, moulded, and directed by any influence except such as have access to the stores of psychical energy which the instinctive activities alone possess. We are thus led to the proposition that the essence of mental conflict is the antagonism of two impulses which both have instinct behind them, and are both, as it were, intimate constituents in the personality of the subject. Thus only can the mind become, in the worn but still infinitely appropriate metaphor, a house divided against itself. The counter-impulses to the developing sexual interest and activity of the child are, as we have seen, the result of social pressure—that is to say, the result of the influence of the human environment. This influence is manifested, not merely in direct precept, in warning, in punishment, in expressions of disapproval or disgust, but in the whole system of secrecy, of significant silences, of suppressions, of nods and winks and surreptitious signallings, of sudden causeless snubs and patently lame explanations amid which such sexual interest as the child possesses has to find a _modus vivendi_ and an intelligible meaning.