Natural Law Theory Is Obviously False

The worst theory in ethics

The most devastating opening statement I’ve ever seen in a debate came from friend of the blog Dustin Crummett in his debate vs Brian Besong.

The debate was about natural law theory. Now, different people mean different things by natural law theory. In the legal profession, it often refers merely to the notion that people have rights that aren’t made by the state. That is emphatically NOT how it’s being used here. The core claims of natural law theory are something like:

1. Morality is solely concerned with one’s own happiness.

2. Happiness is about proper functioning.

3. One should never subvert the proper functioning of one’s faculties for any extrinsic benefit.

Then, in order to get the normative claims of natural law theory, the natural law theorist will need a fourth step like:

4. Lying, gay sex, contraception, masturbation, etc all subvert the function of one’s faculties. In order to avoid absurdity, they’ll also need to think that walking on one’s hands, chewing gum, swallowing little bits of rubber, and drinking Diet Coke don’t do these things.

Natural law theory is a favorite of Catholics. It allows them to explain many moral judgments that Catholics must affirm. For instance, Catholics have to affirm the absolute wrongness of gay sex and contraception. The natural law theorist has a pretty good explanation of why these things might be wrong; the purpose of the sexual faculty (supposedly) is procreation. Thus, if you subvert it by having gay sex—which is not conducive to making babies—you’re doing something wrong.

However, natural law theory suffers from a major problem: it’s just about the most implausible thing ever. Each step is dubious, both individually and in combination. Catholics looking for a reason why you shouldn’t masturbate to stop the holocaust will need to look elsewhere.

Much of what I say will simply be repeating Dustin’s arguments. I’ll organize the objections by which step they’re an objection to, going step by step through the four pillars of NLT laid out above. My view is that there is basically no chance NLT is true, and I find moon landing denial roughly as plausible.

1 Maximizing one’s own happiness

At its core, NLT is egoistic. But egoism isn’t right. So natural law theory is false.

Natural law theory says that the only reason to help other people is that it’s good for your happiness. But this is implausible. The reason to save a drowning child from a pond, say, is partially because it’s good for the child, not just because it’s good for you.

Now, NLTists think that your happiness depends in part on helping other people. So it doesn’t imply that you should be selfish all the time. Still, this gets the order of explanation wrong. Part of why you should help other people is for their sake, not just for your own. Even if natural law theory got the right results (it doesn’t) it wouldn’t get them for the right reasons.

Here’s another bad result of natural law theory: by only being concerned with one’s own happiness, it implies things that are very implausible. Suppose you can tell a lie to prevent your whole family from being tortured to death. NLT says doing so would be wrong because it would be bad for your happiness. But shouldn’t you take a small hit to your happiness so your whole family isn’t tortured to death?

Edit: some commenters have said that NLT isn’t really egoistic—it’s about your “flourishing” not just happiness. Sure, but it still seems like you should take a hit to your flourishing for the sake of others. Seems like your moral reasons are concerned with others’ flourishing too!

2 Happiness is about proper functioning

NLTists think that happiness is about proper functioning. Just as a good car is one that drives well and a good knife is one that cuts well, a good human is one who functions properly.

I don’t think this is true. The sense in which a good car is one that drives well is non-normative. It doesn’t confer any genuine reasons. It’s just a linguistic quirk that we use the same word to refer to cars that function well and people who do the right thing.

There seem like lots of things that are good for you but that don’t improve your functioning. Suppose that you could take a pill which would make you twice as joyous in life. This would be good for you, but it’s not clear it would improve your functioning. Drinking a wholly non-nutritional beverage (say, diet coke) might be good for you without improving your functioning in any way.

I don’t really think there are very deep facts about proper function. We have faculties that evolved for a reason, so there’s some very shallow sense in which it can be said that a faculty has a purpose. That’s the sense in which a heart’s purpose is to pump blood, not make a whooshing sound. But I don’t think these facts are deep or genuinely reasons-giving. This is somewhat controversial, but it means that NLTist is committed to a metaphysical view that’s probably rejected by most working metaphysicians and strikes me as pretty doubtful.

Then, imagine a creature with some horrific proper function. Perhaps its function is to torment and maim—perhaps that’s what it evolved to do, was built to do, or is disposed to do in whatever other way gives something a proper function. It seems that it wouldn’t be right for it to torture and maim. But NLT seems committed to saying that it would be right.

Maybe this is supposed to be impossible? But why? It certainly seems conceivable! It’s unclear what rules it out. Now, maybe the reply would be that God would never create such a creature. But still, a true ethical theory should get the right results in cases that God could choose to actualize if he wanted to, even if he would never choose to actualize it.

Imagine there was a theory that said that it would be okay to press a button that would cause everyone to be tortured for all of eternity. That example would obviously falsify the theory. Nobody would buy the reply “that’s an impossible scenario because God would never choose to actualize it.” There are some scenarios that are impossible but still serve as counterexamples. I don’t have a complete theory of which scenarios are like that. But certainly at the very least, a theory can be falsified by getting a wrong result in one of the scenarios that God could create if he wanted to but never would choose to create because they’re too bad.

Then, lastly, it seems that there can be a giant group of creatures functioning improperly. Imagine that a plague swept through humans, causing all of our eyes to be destroyed. In a few generations, we had no eyes. Still, a properly functioning human would have eyes. Thus, it is possible for all members of a species not to be functioning properly.

But now imagine we learned that actual humans were this way. Our proper function was to be solitary animals who spend our days without clothes, rolling around in the mud. Still, that wouldn’t seem to be good for us. Thus, what’s good for a person isn’t the same as proper functioning.

3 Perverting functions is absolutely wrong

Natural law theory suggests that misusing a faculty is absolutely wrong—you should never do it for any reason. This claim is absolutely wrong.

Start with, say, lying. You should obviously lie to the Nazi at the door about harboring Jews in your house if doing so would save the Jews from being murdered. Similarly, if lying about what you’d have for breakfast would prevent a child from being burned to death, you should obviously do that, and if a view denies this, then it’s totally ridiculous.

The same thing applies to other absolute prohibitions. NLT says that it’s wrong to have premarital sex to prevent everyone from being tortured forever. This seems false. I don’t even think premarital sex is wrong when it doesn’t stop everyone from being tortured for all of eternity, much less when it does.

It’s also not clear why you can’t misuse a faculty to improve overall functioning. Suppose that telling a lie would prevent you from being tortured to death. Wouldn’t this be good for your overall functioning? A person who is tortured to death cannot go on functioning very well. And if it’s better to die than to misuse a faculty, then wouldn’t it be good for a person to die immediately, given that their continued existence will probably lead to misusing a faculty?

The NLTist is also committed to the idea that lying to prevent yourself and your family from being tortured to death would be bad for your happiness. This is implausible. If lying prevented me from being tortured to death, doing so would certainly be good for me!

It’s especially unclear why you can’t misuse a faculty to prevent more future misuses. Suppose that I know that if I don’t lie now, I’ll lie twice later, or if I don’t have premarital sex now, I’ll have it twice later. If lying and having premarital sex are bad for me, wouldn’t this be in my interest? It means things that are bad for me happen less? As best I could tell, Brian Besong’s response to this in his debate with Dustin was to say that you’re still misusing a faculty, but he didn’t give an explanation of why it’s wrong to misuse a faculty for the sake of greater overall use of the faculty.

Weirdly, NLT implies that there are cases where you can kill someone but you can’t lie to them. Imagine a person in a state of temporary insanity barges into your door. In his temporarily insane state, he believes that everyone who has eaten a bagel for breakfast is an alien cyborg trying to kill him. You ate a bagel for breakfast.

“Have you eaten a bagel for breakfast?” he asks you. If you tell the truth, then you’ll have to kill him in self defense. NLT implies that you should kill him rather than telling him a harmless lie. This is absurd. And their explanation of this verdict is that lying would make you unhappy. Seems you should be unhappy rather than kill someone innocent.

4 Lying, gay sex, plastic straws

The natural law theorist says it’s wrong to have gay sex, masturbate, or use contraception because doing so misuses your sexual faculty. That faculty, supposedly, is oriented towards procreation.

But why isn’t chewing gum wrong? You’re misusing your digestive faculty, which is oriented towards nutrition. Or eating food that isn’t nutritious, like little bits of plastic. Or licking stamps? Or wearing noise cancelling headphones, which subvert the hearing function of your ears?

Brian Besong suggests—in his second debate with Amos Wollen, after having a long time to think over the difficult challenge of how his theory secures the result that you can chew a plastic straw to prevent a baby from being tortured—that the chewing faculty is a “coordinative power.” Its purpose is to work with other faculties for your happiness, a bit like the faculty of locomotion. But why not say the same thing about the sexual faculty? Why not say that that’s the purpose of the sexual faculty?

Now, it seems Brian wants to say that there’s a distinction between:

1. Using the digestive faculty for eating, which is properly oriented towards nutrition.

2. Using the digestive faculty in other ways, not oriented towards nutrition.

These are supposed to engage different faculties. But why not say the same thing about sex? There are two faculties:

1. The procreation faculty which is used when one has procreative sex.

2. The non-procreative sexual faculty, which is, like chewing, oriented towards one’s happiness in other ways.

In addition, as Amos Wollen says:

One might argue when one chews sugarless gum without nutritive intent, one is not exercising the nutritive power, and thus are not perverting it; but then it is very hard to see why, say, certain oddly specified acts of prohbited sex can’t appeal use this Get Out of Jail Free card. For instance, Joe Schmid told me on his podcast about a group of “extremely straight” frat guys who temporarily fellated one another—not for sexual pleasure, but because they wanted to know what it felt like from their girlfriends’ POV. Plausibly, they were exercising the power of touch! It’s not clear how the PFA can excuse gum-chewing without also excusing recherché behaviour like this.

[Edit: Joe tells me this is not a real case].

Brian Besong replies to this by suggesting:

Call me old fashioned, but when a guy starts telling other guys he wants to fellate them to “know what it’s like from my girlfriend’s POV,” he’s torched his “extremely straight” card and declared war on the factory that printed it. Equally so for anyone who acts like that’s a legitimate reason to let a man pleasure him. If any these perverts indeed had girlfriends before participating in this debauch, and if these girlfriends had a single degree of self-respect, they would never speak to these degenerates again. Indeed, they would act for all the world like they didn’t know they exist.

Setting aside the weirdness of this passage, whether the case actually occurred is irrelevant. The point is, it’s at least conceivable that someone is this way. So NLT won’t secure the absolute wrongness of gay sex, contra what its advocates say.

Whereas there are a few ways to understand the powers involved in chewing, there is utterly no (plausible) parallel to sodomy. These are quintessentially sexual acts, which is why they involve penile erection and ejaculation if continued.

But you can say an analogous thing about chewing gum. “These are quintessentially digestive acts, which is why they involve salivation and chewing.” Chewing gum is like eating, but it doesn’t involve digestion or swallowing. Gay sex is like straight sex except it doesn’t involve procreation. In both cases, it’s a broadly similar act but it doesn’t achieve the end that the act is supposed to have. So it’s not clear where the asymmetry lies.

5 What’s supposed to be good about natural law theory?

Brian’s core motivation for natural law theory seems to be that it supposedly gets the right verdicts about certain absolutely prohibited sex acts: incest, bestiality, necrophilia, pedophilia, etc. These are supposed to be non-procreative and thus wrong.

I don’t think it gets the right result here. In each of these cases, the acts would still seem wrong even if the kind of sex act generally produced children. Having sex with children would be worse if it tended to cause pregnancy, not better. Similarly, if there was a class of animals that humans could reproduce with, it would still be wrong to have sex with them.

I also don’t think that NLT has any advantage in the sex domain. It has a disadvantage. It implies the wrongness of lots of sex acts that seem permissible (extramarital sex, contraceptive sex, gay sex, masturbation) and it implies you shouldn’t do them to prevent extinction of humanity. Seems false!

It certainly doesn’t seem to help with incest or explaining the wrongness of extramarital sex. After all, incestuous relationships can beget children. Brian responds to this by suggesting that incest tends to beget less healthy children. But:

1. This doesn’t seem like the whole explanation of the wrongness of incest.

2. So do lots of other sex acts. For example, if you have sex with someone who is middle-aged, this has about the same rate of birth defects as if you have sex with your cousin. If the person is sufficiently old, then the rate is similar to if they are your sister. Nonetheless, presumably these classes of acts are not equally wrong. Having sex with someone who is infertile has a lower probability of begetting a healthy child than having sex with your sibling! Thus, it isn’t clear why, given NLT, incest is worse than having sex with someone who is infertile.

Given that NLT needs to add a bunch of weird epicycles to explain the wrongness of these sex acts, I don’t think it has any advantage relative to other theories. For example, here is one theory that seems better: it’s only okay to have sex when every involved party is suitably rational and doing so wouldn’t pervert any relationship that ought to be non-sexual (say, a family relationship). That better captures our intuitions, needs fewer epicycles, and doesn’t have as many crazy implications.

I also don’t really mind biting the bullet on these various sex acts and thinking they’re not intrinsically wrong. Incest, say, usually is a very bad idea. However, if we imagine a case where it leads to no negative consequences, no relationships being damaged, produces no genetically malformed offspring, etc, then it wouldn’t be wrong. Brian seems to treat the most ironclad Moorean judgments as being about the absolute wrongness of certain sex acts that he finds gross; obviously I don’t agree.