Should Taboos Be Taboo?

MIT psychologist Steven Pinker recently delivered an interesting speech to the Foundation for Individual Rights in Education where he argued that we should be extremely skeptical about taboos on the expression of various views [HT: Michael Rappaport]:

Today, I think it is the scientific study of the mind that people tend to blend with deep moral issues. I’ll give you just a few examples of questions that have been raised by people in the field of psychology that have gotten them into trouble because even though they, in theory, are purely intellectual questions, people believe that they shake the foundations of morality. Do most victims of sexual abuse suffer no lifelong damage? Do women, on average, have a different average aptitude in mathematical reasoning than men? Are Ashkenazi Jews on average smarter than Gentiles because their ancestors had been selected for the shrewdness needed in money lending? Is morality just a gadget that evolution installed in our brains with no inherent reality? Are religious beliefs like parasites, which colonize the minds of believers? Is the average intelligence of Western nations falling because duller people are having more children than smarter people?

Do men have an innate tendency to rape? Do women who give birth under difficult circumstances have an innate tendency to abandon or even kill their newborns?…

Why did the hairs on the back of our neck stand up when we entertain purely intellectual research questions such as these?
It brings up a phenomenon called the Psychology of Taboo, the sensation that certain ideas are evil to think. Quite apart from the fact, of course, that certain actions are evil to commit, but can it be sinful even to think a thought?

Pinker argues that such taboos arise and perpetuate themselves because respecting the taboo is a signal of group loyalty:

It’s one thing if your friend or your spouse has been good to you so far, but are they always eyeing a possible better deal? Would they stab you in the back or sell you up the river as soon as the circumstances made it profitable for them? We don’t want to have to constantly ask those questions, and so we seek life partners, coalition partners, friends who are committed through and through, who would not even consider betraying us because it runs against every fiber of their makeup. That is why there is such a thing as the Psychology of Taboo, and all of those questions, which theoretically should be innocent, in fact are corrosive because they require people to think exactly the kind of thoughts that they should not think if they are committed friends, allies, family members.

He goes on to suggest that these kinds of taboos are often pernicious because they tend to stymie research and debate over legitimate issues. And, obviously, the issue identified by Pinker extends far beyond the field of psychology.

By and large, I think Pinker makes a good point. But he misses an important alternative justification for taboos: the sense that some ideas are so dangerous and so manifestly wrong that we must try hard to keep them from spreading lest they do great harm. That sense may be especially strong in cases where we believe the evidence against the idea is overwhelmingly strong, such that further research and discussion is unlikely to add much of intellectual value. Consider, for example, cases such as racism or Holocaust denial. I would put communism on that list as well, given its horrendous record.

The danger, of course, is that our belief that an idea is both extremely dangerous and clearly disproven might be wrong or at least exaggerated. Nonetheless, I am not willing to conclude that there are no ideas that we should treat as beyond the pale.

Obviously, viewing an idea as taboo or beyond the pale is not the same thing as concluding that government should suppress its advocacy. One can believe, as I do, that Nazism and communism should be considered beyond the pale of legitimate discourse, while also believing that Nazi and communist speech should not be suppressed by force.

The question, however, remains: If we are not opposed to treating at least some ideas as taboo, how do we decide which ones?

Pinker himself stops short of giving a clear answer:

I don’t know the answer to that question in every case, but I do know that left to its own devices, human nature will be more outraged, more likely to censor, more likely to be victim to the Psychology of Taboo than would be optimal for the progress of human understanding.

UPDATE: This article by senior Conspirator Eugene Volokh has a lot of good analysis relevant to this question, though it too stops short of providing a complete answer.