Freud begins by remarking that knowledge of human sexuality has been characterized by fixed ideas and errors. The biggest error that Freud will challenge is the belief that children and infants are not sexual beings. Freud also disputes the common notions that the sex drive is fundamentally an instinct toward or an attraction to the opposite sex, that sexual pleasure and functions pertain primarily to the genitals, and that sex is innately procreative in nature.

Freud is, in fact, arguing for a radical expansion of our understanding of what constitutes sexuality, sexual experience, and a person’s sex life. He proceeds methodically. First, he establishes a conceptual framework by naming two distinct aspects of the sexual impulse or instinct: sexual objects and sexual aims. The sexual object is the other person (or, in certain kinds of perversions, not a person but an animal or a thing) whom the sex instinct leads us to find attractive. The sexual aim is the satisfaction sought through interaction with the sexual object.

Having established these distinctions, Freud will argue that the sexual instinct exists entirely independently of any normative sexual object or sexual aim. To establish this, he turns to the sexual perversions. The first so-called aberration that he discusses is homosexuality.