Psychoanalysis affirms the existence of a different real from that of science, a real that is specific to it. While S. Freud posited that psychoanalysis "is a part of science and can adhere to the scientific Weltanschauung", Jacques Lacan would later invite psychoanalysts to consider that there is an irreducible gap between the real of science and the real or "reals" of psychoanalysis. Science discovers knowledge in the real, from which it deduces its laws, which are universal. The gap between the real in science and the real in psychoanalysis is especially palpable where sex is concerned. But where sex is concerned, the gap between the real in science and the real in psychoanalysis can also be measured in relation to certain hesitations in the discourse of science. Human sexuality is not simply rooted in biology; it is subverted by the relation of the subject to language.