or degrade themselves, including suicide, sexual degradation, and drunkenness. This led Kant to regard sexual intercourse as degrading because it reduces humans to an object of pleasure. He admitted sex only within marriage, which he regarded as "a merely animal union." He believed that masturbation is worse than suicide, reducing a person's status to below that of an animal; he argued that rape should be punished with castration and that bestiality requires expulsion from society. Commercial sex Feminist philosopher Catharine MacKinnon has argued that many contemporary practices would be deemed immoral by Kant's standards because they dehumanize women. Sexual harassment, prostitution, and pornography, she argues, objectify women and do not meet Kant's standard of human autonomy. Commercial sex has been criticised for turning both parties into objects (and thus using them as a means to an end); mutual consent is problematic because in consenting, people choose to objectify themselves. Alan Soble has noted that more liberal Kantian ethicists believe that, depending on other contextual factors, the consent of women can vindicate their participation in pornography and prostitution. Animal ethics Because Kant viewed rationality as the basis for being a moral patient—one due moral consideration—he believed that animals have no moral rights. Animals, according to Kant, are not rational, thus one cannot behave immorally towards them. Although he did not believe we have any duties towards animals, Kant did believe being cruel to them was wrong because our behaviour might influence our attitudes toward human beings: if we become accustomed to harming animals, then we are more likely to see harming humans as acceptable. Ethicist Tom Regan rejected Kant's assessment of the moral worth of animals on three main points: First, he rejected Kant's claim that animals are not self-conscious. He then challenged Kant's claim that animals have no intrinsic moral worth because they cannot make a moral judgment. Regan argued that, if a being's moral worth is determined by its ability to make a moral judgment, then we must regard humans who are incapable of moral thought as being equally undue moral consideration. Regan finally argued that Kant's assertion that animals exist merely as a means to an end is unsupported; the fact that animals have a life that can go well or badly suggests that, like humans, they have their own ends. Christine Korsgaard has reinterpreted Kantian theory to argue that animal rights are implied by his moral principles.