Here in a succinct and lovely way is Feser’s distillation of the Perverted Faculty Argument (from his paper of the defense of the same) applied to matters sexual:
- Where some faculty F is natural to a rational agent A and by nature exists for the sake of some end E (and exists in A precisely so that A might pursue E), then it is metaphysically impossible for it to be good for A to use F in a manner contrary to E.
- But our sexual faculties exist by nature for the sake of procreative and unitive ends, and exist in us precisely so that we might pursue those ends.
- So it is metaphysically impossible for it to be good for us to use those faculties in a manner that is contrary to their procreative and unitive ends.
- But contraceptive acts, masturbatory acts, homosexual acts, and acts of bestiality involve the use of our sexual faculties in a manner that is contrary to their procreative and/or unitive ends.
- So it is metaphysically impossible for it to be good for us to engage in contraceptive acts, masturbatory acts, homosexual acts, or acts of bestiality.
- But it can be rational to engage in an act only if it is in some way good for us and never when it frustrates the realization of the good.
- So it cannot be rational to engage in contraceptive acts, masturbatory acts, homosexual acts, or acts of bestiality.
Below, I am going to assume—please don’t laugh—that you have read Feser’s paper in full, so that terms such as unitive, agents, active frustration and so on are no mystery to you. I’ll pause here and wait for you to finish reading.
Done? His defense pertains, as you now know, more than just to sexual matters, but since sex looms large in the modern mind (understandably), it is these matters which provide most of the material. It is here that most attempts at counterexamples are given (or rather, counterexamples are given so as to defeat the arguments supporting traditional sexual morality). On that subject, Feser says:
A genuine counterexample to the perverted faculty argument’s key premise would have to involve an action that both involved the active frustration of the natural end of a faculty and yet which was in no way contrary to what is good for us, not even in a minor respect. I submit that there are no such counterexamples…
I think his argument (supplemented by writings in his other books) is sound: no counterexamples exist. But that does not imply that it not useful to search for them. Every time you think you’ve managed to slip a wedge into a crack, you realize it was not a flaw in the marble of the argument but was instead a fault in your mind. Every counterexample in which you find the flaw strengthens your understanding of the main argument.
Aiding you in your futile search is this admonition:
First, it cannot be repeated too often…that the perverted faculty argument does not entail that there is anything wrong with the use of man-made devices, or the use of a faculty for something merely other than its natural function, or the interference with natural processes where plants, non-human animals, or inanimate objects and processes are concerned.
Remember! We’re after that which is contrary to E and not “different from E” or “other than E.” A counterexample that claims wearing shoes over rocky terrain as opposed to going “naturally” shoeless does not work. Wearing shoes does not frustrate the natural function of walking; they aid in it.
The most commonly thought of supposed counterexamples—such as “Why not watch porno?” or “Why not masturbate when away from home?”—you saw have responses from Feser, so that there is no need for me to repeat what you already read. How embarrassing would it be to give the same examples Feser did!
An example (and not counter) is: “But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart.”
Sin is easy. Overcoming it in this world hard. Constant thinking about purpose—ends, teleology—helps.
Watch the graphic language. I am not at the computer and the spam filter is brutal.