Analogous to the Vestigial

Edward Feser has a fantastic defense of the perverted faculty argument. He intentionally leaves off a defense of his underlying metaphysics, so here’s my attempt to frame what I take as the central objection to that underlying metaphysics.

Consider vestigial organs. For us moderns, these organs are relatively easy to account for: maybe they were made as a genetic fluke, maybe they went along as free riders on a reproductive advantage, but more likely they were once useful adaptations to an environment now gone. Aristotle had no sense of vestigial organs, or if he did it didn’t make much of an impression on his thought, but had he recognized their existence, he would have had no problem impeding their function or removing them altogether.

Thus a partial objection to the perverted faculty argument is to claim that our reproductive system is relevantly analogous to a vestigial organ. I say “relevantly analogous” since it is nonsense to claim that the organs themselves are vestigial. The analogy seems to be that they were adapted to conditions that no longer exist, that is, to a world where human middle age started at about 20 and the replacement fertility rate was around six children per woman. Note we’re assuming (as Feser does also) that our sexual function is more than just the power to reproduce but also the intensity and continuance of the desire and our age on its first onset. Outside the context in which we lived for almost all of our evolutionary history, human sexual functions lose their orientation to the good of survival and can even become contrary to it. Therefore (and this is the point on which the whole objection stands or falls) sexual function can lose its orientation to the practical good of the animal and so cease to be “natural” in the relevant sense in which functions count as natural in the perverted faculty argument.

Another way to put the argument is as a variant of the principle of totality. Just as we would impede the natural function of any organ which would threaten to destroy an individual if we did not impede it, so too we can impede and frustrate natural functions of organs so far as they threaten to destroy us as a species. This seems to be exactly the sort of argument that Paul Ehrlich was making for contraception back in the late 70’s. That said, the irony of arguing that we have to frustrate the very thing that allows for our continuance as a species in order to ensure it is not lost on anyone.

The heart of the objection is the claim that nature does all sorts of things in vain, i.e. we can have all sorts of natural functions (things with an intrinsic teleology) that are nevertheless unconnected to the practical good of the animal. Evolutionary psychology insists on thousands of them, contemporary psychologists have a voluminous literature on them (Stuart Sutherland did a lit review of them in his book Irrationality) and the possibility that functions can be maladaptive follows a priori out of the basic principles of evolutionary thought.



  1. thenyssan said,

    April 16, 2015 at 4:46 pm

    That seems…dire. I always took “nature does nothing in vain” to be an empirical claim. How do you establish it otherwise? Or does something have to take its place?

    • April 16, 2015 at 5:00 pm

      Brandon will refute it pretty soon.

      I’m mindful that the main objection would be that, at best, it justifies some sort of birth-controlling activity without justifying any one in particular – but I tried to rig up the argument so that the organ itself would, while having an intrinsic teleology, still not have a natural activity in the relevant sense that natural law needs. So I tried to keep the main response in mind but I’m still not sure it has what it takes to survive it.

  2. Peter said,

    April 17, 2015 at 2:50 pm

    There was a defense of the church’s teaching on contraception in the Laval journal way back (1970?). I don’t remember the details, but I vaguely recall that it situated the arguments within a modern context of procreation (I remember talk of “eco-systems” or some such). Given that, it might have talked about some of these points, but I really don’t remember the details. It was by Richard Conell and was online for download.

    A discussion of multiple ends would be more worthwhile. Doesn’t Aristotle talk about the tongue like this somewhere (eating, talking, tasting, etc.)? The whole thing about these Aristotelian sex arguments is that (for whatever reason, usually personal allegiances or preferences) different groups defend one end or another to the exclusion of another, or subordinate them differently. Even here the crux is that it might be legitimate to override the obvious function of the sex organs because it (maybe) is frustrated at some other, more indirect level.

    Besides, my first reaction to this argument is to see it as exactly the opposite of an objection. That is, I read it as a call for more celibates, not more condoms.

    • April 17, 2015 at 4:26 pm

      I read it as a call for more celibates, not more condoms.

      I figured that would be the first response, but it doesn’t seem to address the problem that we see species not as having functions relating to a timeless and eternal order of things, but which are appropriate to contingent historical conditions, and this opens the possibility that a teleological function can become alienated from the practical good of the organism.

  3. Peter said,

    April 19, 2015 at 10:15 pm

    Regarding thenyssan’s comment above, here is an interesting passage (De Caelo, Bk. 1, lect. 8):

    “Consequently, it is plain that if there are two contrary circular motions, there would have to be something in vain in nature. But that this is impossible he now proves: Whatever exists in nature is either from God, as are the first natural things, or from nature as from a second cause, as, for example, lower effects. But God makes nothing in vain, because, since He is a being that acts through understanding, He acts for a purpose. Likewise nature makes nothing in vain, because it acts as moved by God as by a first mover, just as an arrow is not moved in vain, inasmuch as it is shot by the bowman at some definite thing. What remains, therefore, is that nothing in nature is in vain.”

    • thenyssan said,

      April 20, 2015 at 6:35 am

      It’s funny, I nearly added “does it have to run through the 5th way?” to that comment I made above. I guess so!

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