Polygamy, the naturalistic fallacy, & gay marriage:

The naturalistic fallacy, looking to nature for what “is” and then attempting to derive a social norm from it (even though the norm clearly is not the way things "ought to be"), is so common that practically no culture throughout human history has been able to avoid engaging in it. Tying this into the gay marriage debate, if we understand how polygamy ultimately was justified under the naturalistic fallacy, this helps us to understand why legalizing gay marriage ought not logically lead to polygamy.

Polygamy certainly is “natural and normal” in that it not only exists in nature but has been the norm of the overwhelming majority of cultures (that is, polygamous marriages did not exist in the “state of nature,” because “marriage” didn’t exist there, but one male having many more than one female partner did indeed exist in the state of nature. In fact it was the norm. In short, one male—usually the Alpha male—dominates many or the entire available crop of fertile females). In all human cultures and societies throughout recorded human history, 83% have been polygamous. And there is a universal within polygamy: It is always one man with more than one wife, (virtually) never the reverse.

A little bit of background as to why this type of polygamy was/is so universal throughout human history and what it has to do with human nature. Men are, by nature, promiscuous seed spreaders. Men are not monogamous by nature, but rather have a natural tendency to gratify themselves with as many women as possible—moreover, men have also tended to monopolize the women whom they have sex with (if they could, if they had the strength, the power & the opportunity to do so). That is, males have tended not to have the attitude “I’ll stick with one in the long term, fool around with many, and only concern my self that my wife stays faithful to me, my concubines can be concubines for whomever else….” No, the Alpha males want to monopolize THE ENTIRE CROP of fertile women. That is, if Solomon has 100 wives, he wants ALL OF THEM TO BE HIS and HANDS OFF to all of the other males.

But there is an obvious problem with this: If men & women are each roughly 50% of the population, and if some men have many wives, then that invariably leads to a shortage marriageable wives for many men. Indeed, Richard Posner, in Sex & Reason, estimates that in the state of nature only 50% of males actually got to spread their seed. Why? The 50% of the “stronger” males—the “Alphas”—monopolized the ENTIRE crop of fertile women. This is universal male behavior. And this is the naturalistic origin, the “is” if you will, of why this type of polygamy has been so universal throughout human history. But we now know better. We know that this is not the way “things ought to be.”

And it’s primarily because of the inherent inegalitarianism of polygamy (yes nature can be very inegalitarian, the state of nature sure was) that it is unfair to both the women involved in these relations, and especially to the non-Alpha males who were deprived of mates.

But so many cultures, including that of the Old Testament—a book written by men much closer to the “state of nature” than we are now—and currently, many notables such as Islam, have vetted polygamy. Why? The naturalistic fallacy. This is simply the way things are, were, have always been, and the way nature inclines males, the physically stronger of the two sexes and hence the ones who will be dominant in the “state of nature,” to behave. But this is one of those “natural phenomena” that needs societal correction. And that correction is the institution of monogamy, the requirement that one man only gets one woman (or at least one consenting woman at a time) for his life. Thus, the policy behind prohibiting polygamy has nothing to do with, (is wholly distinguishable from) gay marriage. (Hat tip to Jonathan Rauch, who makes a similar argument in his excellent new book, Gay Marriage: Why it’s Good for Gays, Good for Straights, and Good for America.)