Response from Thomas Pogge on June 13, 2007

Kant better not say this. If everyone remained childless, then there would be no new babies either. So, by the same token, Kant would be condemning his own decision to remain childless.

A good way of showing how remaining childless can be seen as permissible on Kant's ground is to interpret the categorical imperative as asking whether one can will not the universal adoption, but rather the universal availability of one's maxim. In a world in which enough children are born by to those who want to have children, I can will my maxim of remaining childless to be universally available: Even if everyone who wants to adopt this maxim does so, humanity will still continue.

Applying this interpretation of the categorical imperative to homosexuality, it turns out that homosexuality is likewise permissible. Even if I cannot will humankind to go extinct, I can will the universal availability of a homosexual life: There are enough heterosexuals who want to have children to propagate the human race.

What if things became different one day? What if nearly all human beings came to want to lead the childfree life of a scholar, or the childfree life of a homosexual? In that case -- assuming again that we cannot reasonably will rational nature to disappear -- we'd all have a duty to do our bit to help propagate the race.

This is not, I confess, what Kant would have said about homosexuality. In harmony with his era, Kant had contempt for homosexuality and deemed it important that his morality should be able to reaffirm this contempt. It is heartening, then, that a plausible reading of Kant's theory fits better with our more progressive views about homosexuality than with those of Kant's time. What Kant should have said, by the lights of his own theory, is alright.

Response from Alan Soble on June 17, 2007

A few additional remarks. Kant's explicit condemnation of homosexual (or same-sex) sexual relations can be found in his Lectures on Ethics (the Vorlesung). His arguments are grounded in the Second Formulation of the Categorical Imperative (not the First, as suggested by the question), but mostly on his claim that homosexual acts are unnatural, "crimes against nature." For two essays on this apsect of Kant's views, see my "Kant and Sexual Perversion" The Monist 86:1 (Jan. 2003), pp. 55-89 -- also available at http://fs.uno.edu/asoble/pages/kmonist.htm -- and Lara Denis, "Kant on the Wrongness of 'Unnatural' Sex," History of Philosophy Quarterly 16:2 (1999), pp. 225-48. Finally, John Corvino's essay "In Defense of Homosexuality" (in A. Soble, ed., The Philosophy of Sex, 5th edition) includes this passage: "A Roman Catholic priest once put the argument to me as follows: 'Of course homosexuality is bad for society. If everyone were homosexual, there would be no society.' Perhaps it is true that if everyone were homosexual, there would be no society. But if everyone were a celibate priest, society would collapse just as surely, and my friend the priest didn’t seem to think that he was doing anything wrong simply by failing to procreate. Jeremy Bentham made the point somewhat more acerbically roughly 200 years ago: 'If then merely out of regard to population it were right that [homosexuals] should be burnt alive, monks ought to be roasted alive by a slow fire.'"