Taboo, Coordination, and the Game of Reasons

The other night I was talking to my roommates about family, communes, thick normative concepts, and the nature of not-further-questionable reasons for action. Among our topics: Can “Because she's your sister” be sufficient reason for doing something? Why “Why should I care that she's my sister,” is both a necessary and unacceptable question.
This bit of Pinker's excellent discussion of the Summers controversy reminded me of our conversation, which had absolutely nothing to do with women and math:

What are we to make of the breakdown of standards of intellectual discourse in this affair–the statistical innumeracy, the confusion of fairness with sameness, the refusal to glance at the scientific literature? It is not a disease of tenured radicals; comparable lapses can be found among the political right (just look at its treatment of evolution). Instead, we may be seeing the operation of a fascinating bit of human psychology.

The psychologist Philip Tetlock has argued that the mentality of taboo–the belief that certain ideas are so dangerous that it is sinful even to think them–is not a quirk of Polynesian culture or religious superstition but is ingrained into our moral sense. In 2000, he reported asking university students their opinions of unpopular but defensible proposals, such as allowing people to buy and sell organs or auctioning adoption licenses to the highest-bidding parents. He found that most of his respondents did not even try to refute the proposals but expressed shock and outrage at having been asked to entertain them. They refused to consider positive arguments for the proposals and sought to cleanse themselves by volunteering for campaigns to oppose them. Sound familiar?

The psychology of taboo is not completely irrational. In maintaining our most precious relationships, it is not enough to say and do the right thing. We have to show that our heart is in the right place and that we don't weigh the costs and benefits of selling out those who trust us. If someone offers to buy your child or your spouse or your vote, the appropriate response is not to think it over or to ask how much. The appropriate response is to refuse even to consider the possibility. Anything less emphatic would betray the awful truth that you don't understand what it means to be a genuine parent or spouse or citizen. (The logic of taboo underlies the horrific fascination of plots whose protagonists are agonized by unthinkable thoughts, such as Indecent Proposal and Sophie's Choice.) Sacred and tabooed beliefs also work as membership badges in coalitions. To believe something with a perfect faith, to be incapable of apostasy, is a sign of fidelity to the group and loyalty to the cause. Unfortunately, the psychology of taboo is incompatible with the ideal of scholarship, which is that any idea is worth thinking about, if only to determine whether it is wrong.

At some point in the history of the modern women's movement, the belief that men and women are psychologically indistinguishable became sacred. The reasons are understandable: Women really had been held back by bogus claims of essential differences. Now anyone who so much as raises the question of innate sex differences is seen as “not getting it” when it comes to equality between the sexes. The tragedy is that this mentality of taboo needlessly puts a laudable cause on a collision course with the findings of science and the spirit of free inquiry.

Pinker points toward the coordinative functions of taboo. Adherence to taboos signals unconditional cooperation or an unconditional disposition to punish (usually the latter), providing a clear structure for coordination. Because family solidarity is, in most cultural contexts, so important, defecting on a family member has the character of a taboo. The taboo authorizes extreme reprisals and often requires altruistic punishment that is “irrational” in the technical sense, but which creates a payoff structure that is not a prisoner’s dilemma, i.e., in which it is not rational to defect.
So if I say, “Because she’s your sister.” And you say, “Why should that matter?” it is not that you’re asking an essentially illegitimate question, but that you have signaled non-commitment to the taboo-laden game structure, and thus identified yourself as a potential defector who must be given some additional reason not to defect. There may be some additional reason that is readily available. But insofar as speech acts are moves in the game, the correct response may not be to provide the additional reason, but to begin altruistic punishment immediately in an attempt to reinstate the more reliably cooperative game structure. So, it would not be unexpected, nor necessarily strategically irrational for “Why should I care that she’s my sister?” to be answered with a hard slap to the face.
But a slap in the face is, as Pinker puts it, “incompatible with the ideal of scholarship,” or rational inquiry. If the game is inquiry, then we have to question the taboos. One might worry that the entire family solidarity taboo structure is unjustified, especially given the cultural evolution of family structure. Fair enough. But then it is crucial to make it abundantly plain what game is being played. And if you attempt to play the inquiry game with your family, they might fairly suspect that your motivation to introduce the inquiry game is really to change the structure of the family game, which they will likely resist. So you end up in a third game, where the inquiry game is resisted in order to prevent the introduction of uncertainty into the family game by the rational undermining of stable norms.
(Now that I think of it in these terms, I realize that I played this third kind of game constantly with my mother in Sunday school. I would ask what I took to be a penetrating theological question, and she would resist answering on the terms of the game I had introduced, lest she undermine the norms of faith to which she was attempting to commit her son.)