I’ve taken up an old hobby again: rambling about moral philosophy. Science writer John Bohannon (creator of the “Dance Your PhD” competition) started a blog about bioethics, and I’ll be contributing posts and comments there.

The blog, called “The Electric Monk,” is a collaboration between bloggers from around the country who are interested in the ethical problems posed by advances in medicine and science. If you’re in a serious mood, check out my response to a recent post, “What is wrong with incest?” after the jump.

This comment is a reaction to a recent news article about the case of Josef Fritz, an Austrian man convicted of imprisoning his daughter for 20 years and raping her repeatedly. There are many reasons that this crime is morally reprehensible, but how big of a factor does incest play in our intuition of its “wrong-ness”? For example, as psychologist Jon Haidt asks us to consider: what if the incest were a single, mutually consenting act between brother and sister, and who use contraception so there are no physical consequences of the act? Is incest still immoral then?

I think our repugnance for incest is an evolutionary vestige. Being able to perceive the “ick factor” of incest helped us decrease the risk of genetic disease in our offspring, and we created social mores around this intuition to enforce it. Now with contraception, incest doesn’t cause evolutionary harm, but we’re still left with the social and psychological conditioning that says it is harmful.

Does this mean incest isn’t wrong anymore, and we should go against our (now useless) instincts? Depends on how you view morality. First of all, I think we can all agree on the following:

1. The Fritzl case is repulsive because it involves incest and a betrayal of familial trust (i.e. lack of consent).
2. However, it is wrong only because of the non-consensual aspect. We’re unsure whether the incest is wrong in itself.

I think that in drawing a line between what is “wrong” and what is merely “repugnant,” we are implicitly assuming that moral reasoning must be rational. If our “ick factor” in response to incest can’t be justified by a reasoned process, then we are hesitant to elevate that intuition to the status of a true “moral” value. In other words, it’s not enough to say that something is wrong because it is repugnant. We have to find a reason why it is wrong based on rational–and somehow objective–analysis.

Haidt’s example about the brother and sister challenges us to question this assumption of rationality. Since there is nothing in our modern liberal mindset to deny them the right to their own idea of pleasure, why do we still feel an instinctive repulsion to the idea? Is it not “wrong” anymore? Maybe there is something more to the feeling of repugnance. And as Haidt points out elsewhere in the paper (pdf), even the “reasoned process” behind seemingly legitimate moral values can be reduced to a series of post-hoc rationalizations. We construct morality to bolster judgments that first formed as intuitions, not the other way around. If you’re a liberal on gay rights, you’ll see this in John Finnis’ condemnation of homosexuality (pdf, p.4). If you’re a conservative, chances are you’ll find his arguments the epitome of carefully reasoned moral philosophy.

One quick conclusion from all this is that our instincts matter just as much as supposedly “rational” moral values. Maybe “repugnant” and “wrong” aren’t separate qualities of an act, but both ways of tapping into the same deep-rooted adaptive instinct that we all have. Incest isn’t necessarily wrong because it is bad — it is wrong because it used to be bad, and that badness is still encoded in our psychology and communal values.

“What’s wrong with incest?” at the Electric Monk