Arguing about taboo topics

Uwe Reihnardt has a great post at Economix about the absurdity of various requirements that the health care reform is expected (by probably the most of public debate participants) to meet. Before going on to write about healthcare itself, I'd want to use one of Reinhardt's observations to illustrate a more general point. He writes:

Cost-effectiveness analysis should never be the basis of any coverage decision by public or private third-party payers in healthcare, for to do so would put a price on human life - which, in America, unlike everywhere else, is priceless.

When you look at what people do as opposed to what they say, it seems though that no one actually thinks their life is priceless. For example, pretty much all of us have at some point made a choice tantamount to accepting a small (but non-zero) risk of dying in exchange for some benefit in terms of the quality of life. Like, for example, flying or driving. If we truly thought the monetary value of preserving our life is infinite, we should never choose to drive or ride a car, unless the car is an ambulance and we're in the middle of a massive heart attack. The fact that we do not think the value of our life is infinite can also be inferred from the amounts we're willing to pay to avoid certain risks. This research shows, for example, that most of us will pay $5 to avoid a one in a million chance of dying, but will not pay $20 for the same opportunity.

So our actions reveal that we do not really think that life, even our own, is priceless. What we acknowledge in our words, however, is a totally different matter. "Life is priceless" is a rhetorical taboo and, contrary to Reinhardt, not just in America. If you ever try to argue that the value of human life is finite, sooner or later you will hear as a counter-argument that you must therefore believe the value of human life is zero. This is a curious argument, and as commenters in this thread point out, it's more general than just this particular case. There are more rhetorical taboos that follow the same pattern. Say you have a continuum of policy choices in some interval with policies A and B at the opposing ends of it. You then try to argue in favor of some policy mix (1-x)A+xB where x is neither zero nor one. If A and/or B are taboo policies, then pretty soon you'll have B-supporters telling you that if you think x can be anything less then one it must mean you think it's zero, and so you really don't care about B at all, and/or A-supporters accusing you of thinking that x should be equal to one and so you don't care about A either. If there actually is a continuum, those accusations are patently absurd; but, apparently, hard-core supporters of the extremes view the choice space as a dichotomy, not a continuum. To them, the choice is between all A and all B; nothing in between is possible.

Game theory has a lot to say about the rationality of taboo. However, what it does say is mostly about taboo actions; but what could be the worth of taboo rhetoric, especially in cases where speakers' actions belie their own words? I think the purpose of such professed beliefs is to signal two things at once: group membership and loyalty. By saying "Anything less than all A is in fact all B" you identify yourself as an A-supporter, but also as someone who, once she establishes a relationship with her allies, is unwilling to reconsider that relationship upon hearing arguments against her preferred policy choice. In other words, someone loyal. The signaling is done via showing your fellow A-team members that you consider anyone who argues that maybe there's too much A and not enough B in the world to belong to the camp that wants to rid the world of all traces of A altogether. That is because anyone who tries to argue to an A-supporter in favor of something "in between A and B" is most likely to be one of two kinds of people. Either he's a B-supporter trying to hide his true colors, or he's someone who actually tries to figure out what mix of A and B is best for whom. The latter kind of people can be dangerous too, because they tend to be "overly rational" and therefore disloyal. They might convince you to become their ally and join forces in doing something together; but they always doubt whether the alliance they're currently in is really the one that's best for their interests. And if they decide otherwise, they will break the relationship they talked you into with no qualms and move on to look for a better one.

Now from a logical point of view, of course, things like that shouldn't be considered at all. Logically, the only thing that matters for evaluating an argument is its substance; it doesn't matter at all who's talking, only what they're saying. But if the true point of a debate is not to try and find out the truth behind various possible policy choices, but rather to signal things like team membership and strength of loyalties, we shouldn't expect substance to be very important. Yes, arguing ad hominem is logically incorrect; but if the criteria for winning the debate are something other than logical correctness, it could still be an effective rhetorical strategy. Conversely, the fact that arguments ad hominem actually are very effective in political debates is, I think, strong evidence telling us that the purpose of those debates is not to find the highest quality arguments with which to persuade those who disagree with you, but something else altogether.