Evaluation of Feser’s Perverted Faculty Argument

This evaluation of Edward Feser’s* argument for traditional Catholic sexual morality is not a digression from my series of posts on the conceptual elements of moral thinking. The main point of my evaluation is to bring out that in moral thinking “ought” is moral fundamental than “good.” Or: thinking of what we ought to do is more fundamental than thinking of good to be accomplished by what we do.In the terminology of moral theory, I am making a case that moral thought is fundamentally deontological as opposed to teleological. Correct moral theory brings out that choices are to be driven by duty as opposed to being drawn by a goal (telos) of what is good.

I might be evaluating Feser’s article by a standard different from what he was trying meet. Feser’s goal might have been simply to show the correct formulation of the argument in the tradition of Aristotelian-Thomistic moral theory. I am evaluating his argument on the basis of whether or not it is an effective argument for the correctness of the basic principle of Catholic sexual morality.

To be an effective argument for the basic principle of Catholic sexual morality, the final conclusion has to be a statement that we OUGHT to follow the restrictions of Catholic sexual morality. A frequent criticism of natural law moral arguments is that they infer from a claim that there IS a way a system operates to a claim that that is the way we OUGHT to use the system.

For example,

The function of sexual intercourse IS to unite a man and woman in a union for procreation an rearing of children.
Therefore, sexual intercourse OUGHT to be used for uniting a man and woman in a union for procreation and rearing of children.

Feser writes on p. 381
No such gap, and thus no “fallacy” of inferring normative conclusions from “purely factual” premises, can exist given an Aristotelian Thomistic essentialist and teleological conception of the world.

But I challenge his argument mainly because we should not rest our argument on a conception of the world without admitting that such an assumption is taking a stance and thereby conceding that our argument is contingent upon that stance being correct. Moreover, I think that even if he explicitly conceded that he is taking a stance, he still makes a logical leap from “is” to “ought”
if his intention is to show that people ought to conform to traditional sexual morality.

It is in the use of metaphysics to justify moral claims about what people in the natural world ought to do where there might be inferences from “is” to “ought.”

In claims about the natural world, from an Aristotelian perspective, there may be no significant factual statement which does not also entail an “ought” statement because significant factual claims about any natural individual, species or system at least implies a claim about a final cause for the individual, species or system. However, factual statements entail an “ought” because there is an implicit premise to the effect:

If at the metaphysical level we can characterize a being with an essence E as choosing goal G, then at the natural level we can say that a being with essence E ought to choose G.

Such a premise should be explicit when used.

Consider Feser’s argument for traditional sexual morality. I present his whole deductively argument because it is so elegant. With the discussion of the premises in the article it is a clear and rigorous argument from Aristotelian-Thomistic metaphysics that conformity to traditional Catholic sexual morality IS an essential feature of a rational animal. But I focus only on the first and last premise.

His first premise as I mark it explicitly places his argument in metaphysics and not in physics.

1. 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.

2. 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.

3. 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.

4. But contraceptive acts, masturbatory acts, homosexual acts, and acts of
bestiality involve the use of our sexual faculties in a manner that is con
trary to their procreative and/or unitive ends.

5. 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.

6. 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.

His conclusion is still at the metaphysical level. It tells us what is true about the essence of a rational animal.

7. So it cannot be rational to engage in contraceptive acts, masturbatory acts, homosexual acts, or acts of bestiality.

I use his term “metaphysically impossible” to emphasize that the conclusion is still a metaphysical claim.

So it is metaphysically impossible to be a rational animal and to engage in contraceptive acts, masturbatory acts, homosexual acts, or acts of bestiality.

Unfortunately it is all too obvious that it is physically possible to be a rational animal and to engage in contraceptive acts, masturbatory acts, homosexual acts, or acts of bestiality.

How can there be such a disparity between metaphysical truth and physical truth? The quick answer is that we are not as we ought to be. We get distracted by goods which are not our true good. So we do not choose as a fully rational animal would choose. We ought to choose as a fully rational animal would choose. And here we have the “ought” following from an “is.”

We need a premise (8) along the lines of:

8. We ought to choose and act on the physical or natural level as a rational animal characterized at the metaphysical level

* See Ch. 16 “In defense of the perverted faculty argument”
by Edward Feser in Neo-Scholastic Essays St. Augustine Press, South Bend IN 2015,

My book Confronting Sexual Nihilism: Traditional Sexual Morality as an Antidote to Nihilism was released by Tate Publishing on March 11, 2014. See Book Web Page for information about the book. In Ch. IV of my book I make a case for traditional Catholic sexual morality. If I were to prepare a 2nd edition of my book I would think of using Feser’s argument because I think it is persuasive. I would only add that I am explicitly assuming a stance and I do need to add an “ought” premise. Free copies can be obtained here by credit card by paying $3.75 for shipping and handling.





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