Then the act of sucking the breast would be a nutritive act and at the same time a sexual act, a sort of combination of the two instincts. This seems to be Freud’s conception. The obvious coexistence of the two instincts, or rather their manifestation in the form of hunger and the sexual drive, is found in the life of adults. But at the infantile stage we find only the function of nutrition, which sets a premium on pleasure and satisfaction. Its sexual character can be argued only by a petitio principii, for the facts show that the act of sucking is the first to give pleasure, not the sexual function. Obtaining pleasure is by no means identical with sexuality. We deceive ourselves if we think that the two instincts exist side by side in the infant, for then we project into the psyche of the child an observation taken over from the psychology of adults. The co-existence or separate manifestation of the two instincts is not found in the infant, for one of the instinctual systems is not developed at all, or is quite rudimentary. If we take the attitude that the striving for pleasure is something sexual, we might just as well say, paradoxically, that hunger is a sexual striving, since it seeks pleasure by satisfaction. But if we juggle with concepts like that, we should have to allow our opponents to apply the terminology of hunger to sexuality. This kind of one-sidedness appears over and over again in the history of science. I am not saying this as a reproach: on the contrary, we must be glad that there are people who are courageous enough to be immoderate and one-sided. It is to them that we owe our discoveries. What is regrettable is that each should defend his one-sidedness so passionately. Scientific theories are merely suggestions as to how things might be observed.