Let's see. Does this count? Ludwig Wittgenstein, Zettel #504: Love is not a feeling. Love is put to the test, pain not. One does not say:"That was not true pain, or it would not have gone off so quickly."[Liebe ist kein Gefühl. Liebe wird erprobt, Schmerzen nicht. Man sagt nicht:"Das war kein wahrer Schmerz, sonst hätte er nicht so schnell nachgelassen."] [ Zettel , ed. G. E. M. Anscombe and G. H. von Wright(Berkeley, Calif.: University of California Press, 1970), pp. 89, 89e.] Probably not. There has been gossip, some perhaps mildly confirmed, about his homosexuality (e.g., his taste for rough trade), and the possible influence this had on his ethics. Beyond that--you're right. Nothing. Still, take a look at "Wittgenstein, Ludwig," by Wendy Lynne Lee, in Soble, ed., Sex from Plato to Paglia: A Philosophical Encyclopedia , vol. 2, pp. 1076-1081 (Greenwood, 2006). Lee does admit at the outset that she will be discussing three "Wittgensteinian themes" that bear upon sexuality. I doubt we can do...

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.'...

Plato had much to say about love and sexual desire in his dialogues Symposium and Phaedrus and elsewhere (e.g., Laws , Lysis , Republic ). What we call "Platonic Love," however, may bear little resemblance to what Plato had in mind; "Platonic Love" might be a medieval or Neoplatonist corruption or variation of Plato's own ideas. Be that as it may, we don't talk about "Aristotelian Love" because it is a mouthful. Aristotle did talk about "love," in the sense of friendship, using the Greek word "philia" instead of Plato's word of choice, "eros." For Aristotle's account of friendship, see his Nicomachean Ethics ; the relevant passages, as well as commentary, can be found in my Eros, Agape, and Philia . Also take a look at Gilbert Meilaender's "When Harry and Sally Read the Nicomachean Ethics : Friendship between Men and Women," in Leroy S. Rouner, ed., The Changing Face of Friendship ( Notre Dame, Ind.: University of Notre Dame Press, 1994), pp. 183-96. You might also want to...