Among the many subjects of the philosophy of sex, there is permissible sexuality. Philosophy, however, sometimes tends to over-intellectualize the debate. What makes sex permissible may not be so strict. Drawing on Immanuel Kant's formulation of humanity, I argue that permissible sexual relations require only informed and voluntary consent, but on two conditions, which Thomas Mappes generally gets right. Next, I turn to Howard Klepper and argue that he is only half right in his explanation and that permissible sexuality need not go beyond consent and its two conditions. In the formulation of humanity from the Metaphysics of Morals, Kant argues that we should treat humanity, in ourselves or others, not only as a means, but also as an end in itself. Thus, according to Kant, sexuality is never permitted, except within the framework of marriage. He says: Say no to plagiarism. Get a tailor-made essay on "Why violent video games should not be banned"? Get the original essay There is only one condition under which [sex] is possible: that if a person is acquired by the other as if it were one thing, the one who is acquired acquires the other in turn; because in this way everyone reclaims and restores their personality. But to acquire a member of a human being is at the same time to acquire the whole person, since a person is an absolute unit. Thus, not only are the sexes allowed to abandon and accept each other under the condition of marriage, but it is possible for them to do so only under this condition (“Duties towards the Body”, 142). This means that it is impossible to possess a person without violating the formulation of humanity unless that person also possesses you. So while you are possessed, you become your own possession again by possessing the person who possesses you. And for Kant, once again, this is only possible in marriage. In any other sex, both partners simply use each other as objects of sexual pleasure. Even if they both consent, their sex is not permissible according to Kantian standards. That only marriage can satisfy the formulation of humanity has troubling consequences for Kant's account. First, it means that gay and lesbian sexuality is also permitted if it takes place within a monogamous, loving marriage. Kant characterizes homosexuality as crimina carnis contra naturam as going against the ends of humanity and an abuse of sexuality (“Crimina Carnis” 144). Yet it follows that a same-sex relationship can be permitted simply if it meets the conditions of marriage. Second, what about a loveless marriage? It is very possible that a married couple, who no longer love each other, perhaps on the verge of divorce, could have sexual relations similar to those that strangers can have. Marriage is not enough to guarantee the formula of humanity. In marriage as described, nothing, in practice, separates one sex from another. Does the fact that they are married guarantee that they will treat each other to their ends? Kant is surely not wrong, but perhaps he should not limit his considerations to marriage alone. There are other problems with the formulation of humanity. The wording does not necessarily speak of human beings but of the humanity in human beings. We must view humanity, or the ability to reason and pursue our own ends, as an end in itself. This means that when we employ the services of a carpenter for example, if he has freely decided to engage in carpentry and has agreed to provide us with hisservices, we are allowed to use these services as a means when we act in a way to which he consents by, for example, paying him for his work. To return to the subject, it follows that one can do the same with a prostitute if both parties agree. Kant's formulation should therefore not be limited to simple marriage. We are able to satisfy this formulation and treat humanity as both a means and an end as long as we respect our partner's ends and obtain mutual consent. And this is exactly what I argue: informed and voluntary consent, described by Thomas Mappes in his story, is in fact sufficient to make sex permissible, that is to say to use others sexually as a means and an end in self. However, this is only true if we satisfy both Mappes conditions. We must (1) not lie or withhold information, and (2) threaten and coerce when we have sex. Both conditions are necessary, because we must remain ethical, but not to the extent that Mappes describes. We violate the first condition only with regard to sex itself. In other words, we only violate informed consent if we lie about wanting to have sex without intending to give our partner an orgasm. We also violate informed consent if we lie about sexual illnesses or deceive our partner into procreation. Thus, according to Mappes' account, only scenarios (2) and (3) seem to constitute a violation (Mappes, 234). Lying about having an orgasm — or rather not giving your partner an orgasm — is a violation of informed consent, because consenting to sex without having an orgasm isn't really sex. Lying about procreation is a violation, because consenting to sex but rather procreation - assuming procreation was mutually agreed to be excluded - is not sex, but something else. And lying about having a sexual illness actually violates both conditions. All three of these are violations of the first condition because they directly lie about sex itself. If two partners consent to sex, they must have sex, anything other than sex violates informed consent. In all other cases, Mappes lists a few, but we can imagine other scenarios, the degree of specificity and/or explicitness of consent being vague. Beyond the scope of sex itself, it is difficult to extend the thinking further to what is relevant. When both partners consent, what exactly are they consenting to? They cannot consent to everything during and after sex, nor to anything that may be closely related to the decision-making process. The second condition dictates that we must not threaten or coerce, otherwise sexual relations are not voluntary and therefore permitted. This condition is obvious; harming others is immoral. Coercive offers, however, do not meet this criterion. In case 6 (Mappes, 240), Mappes simply assumes that in the event of refusal, the professor would abuse his authority and retaliate against the student because his offer is an implicit rather than a verbal threat. But again, this is a big assumption on Mappes' part and it doesn't pan out. Thus, only a threat constitutes a violation of voluntary consent. Overall, as long as the people involved consent and the two (revised) conditions are met, there can be no objection to casual sex, sex with strangers or prostitution, etc. Sexual relations.