The philosophy of sexuality, like the philosophy of science, art or law, is the study of the concepts and propositions surrounding its central protagonist, in this case ‘sex’. Its practitioners focus on conceptual, metaphysical and normative questions.
Conceptual philosophy of sex analyses the notions of sexual desire, sexual activity and sexual pleasure. What makes a feeling a sexual sensation? Manipulation of and feelings in the genitals are not necessary, since other body parts yield sexual pleasure. What makes an act sexual? A touch on the arm might be a friendly pat, an assault, or sex; physical properties alone do not distinguish them. What is the conceptual link between sexual pleasure and sexual activity? Neither the intention to produce sexual pleasure nor the actual experience of pleasure seems necessary for an act to be sexual. Other conceptual questions have to do not with what makes an act sexual, but with what makes it the type of sexual act it is. How should ‘rape’ be defined? What the conceptual differences are, if any, between obtaining sex through physical force and obtaining it by offering money is an interesting and important issue.
Metaphysical philosophy of sex discusses ontological and epistemological matters: the place of sexuality in human nature; the relationships among sexuality, emotion and cognition; the meaning of sexuality for the person, the species, the cosmos. What is sex all about, anyway? That sexual desire is a hormone-driven instinct implanted by a god or nature acting in the service of the species, and that it has a profound spiritual dimension, are two – not necessarily incompatible – views. Perhaps the significance of sexuality is little different from that of eating, breathing and defecating; maybe, or in addition, sexuality is partially constitutive of moral personality.
Normative philosophy of sex explores the perennial questions of sexual ethics. In what circumstances is it morally permissible to engage in sexual activity or experience sexual pleasure? With whom? For what purpose? With which body parts? For how long? The historically central answers come from Thomist natural law, Kantian deontology, and utilitarianism. Normative philosophy of sex also addresses legal, social and political issues. Should society steer people in the direction of heterosexuality, marriage, family? May the law regulate sexual conduct by prohibiting prostitution or homosexuality? Normative philosophy of sex includes nonethical value questions as well. What is good sex? What is its contribution to the good life?
The breadth of the philosophy of sex is shown by the variety of topics it investigates: abortion, contraception, acquaintance rape, pornography, sexual harassment, and objectification, to name a few. The philosophy of sex begins with a picture of a privileged pattern of relationship, in which two adult heterosexuals love each other, are faithful to each other within a formal marriage, and look forward to procreation and family. Philosophy of sex, as the Socratic scrutiny of our sexual practices, beliefs and concepts, challenges this privileged pattern by exploring the virtues, and not only the vices, of adultery, prostitution, homosexuality, group sex, bestiality, masturbation, sadomasochism, incest, paedophilia and casual sex with anonymous strangers. Doing so provides the same illumination about sex that is provided when the philosophies of science, art and law probe the privileged pictures of their own domains.