....whenever incest occurs it creates an informational externality that makes it more rational for relatives to misinterpret non-sexual affection for amorous advances. Incest between consenting adults therefore harms society and consequently is not just a private affair.
Whereas:
Homosexuality can also create informational externalities, but these externalities are unavoidable and so do not provide a justification for criminalizing gay sex.
Also, "Criminalizing gay sex... would not reduce the number of homosexuals and would thus not decrease the probability of someone thinking any given heterosexual man was gay," he says.
It's not his purpose I question, but his argument. I don't know anything about game theory, but I don't think that's why I had a hard time following his logic.
People interpret or misinterpret gestures of affection all the time based on their experience, not social codes. In fact, while Miller says that "In a world in which incest is taboo and rare most people won't interpret a hug from a relative as a sign of sexual interest," I'm guessing that it's the rarity rather than the taboo that causes Niece Becky to interpret Uncle Joe's big, warm hug as avuncular rather than lecherous. And there are nieces who would take their uncle's hug as lecherous. Some uncles are, indeed, leching, and some nieces are damaged by prior experiences that would make them shudder at even an innocent, familial touch.
There are potent taboos, as well as laws, against the sexual abuse of children, and given the negative attention given to cases of such abuse in recent years, we can assume these taboos are stronger, not weaker, than before. But that didn't help the Ameraults and Kelly Michaels, whose insane prosecutions on bogus molestation charges were famously debunked by Dorothy Rabinowitz. These colossal "misinterpretations" were not the result of any weakening of the taboos. In fact, you could argue that they were caused by an obsession with them.
Again, Miller's heart is in the right place, but I don't think the slide-rule approach strengthens his case. In a way, I think his approach makes the argument against sodomy laws more abstruse and difficult.
A lot of the Santorum-centric discussion I've been reading has been about the harm to society, or lack thereof, of gay sex. I take that point as irrelevant, because to a large extent societies police themselves on that score.
It's certainly that way here. Few would dispute that American society is more comfortable now with gay people than it was twenty years ago. (That's why this discussion is hot -- maybe why it's taking place at all.) You couldn't say this development was caused by laws or taboos -- unless you were strongly against tolerance of gay people. Then you might argue that the sexual revolution, Roe v. Wade, Will & Grace, etc., were among those "informational externalities" that have weakened the nation's moral fiber and sent us hurtling down the road to Gomorrah. And you might, within that argument, call for strengthening those taboos by retaining laws against sodomy.
In other words, Miller and Sullivan are playing on the Right's turf. They're accepting the premise that morality is, and should be, as enforcible by law as utility, but raising a wan demurrer: that the externality represented by the homosexual state is "unavoidable," and thereby protected from the terms of that premise. Next, of course, someone will argue with "unavoidable," and we're off to the races again.
Like I said, I don't know about game theory, but I do perceive that sodomy laws do not protect as many real people as they harm, and I'm against them. And I'm frankly more respectful of the counter-argument that these laws give prosecutors extra leverage in convicting rapists than I am of most arguments based on anyone's theory. Because at least that argument's happening on planet Earth.