How I Spent My Summer Vacation

by on August 29, 2008 · 6 comments

Read Recently: The Marriage of Elizabeth Barrett Browning and Robert Browning. A remarkable and very non-technological story.

Also: Most of John Dupre’s book Human Nature and the Limits of Science. This turns out to be a critique of two models of human nature, one derived from evolutionary biology and evolutionary psychology, and the other derived from economics. Dupre favors a view of human nature more closely linked to culture, acknowledging the value of diversity. This is a topic well worth writing about; unfortunately, this particular book would have benefited from a vigorous pre-publication critique. Reading it is a lot like having a very frustrating dinner conversation with Dupre, in which interesting arguments are stumbled over, explained only partly, and then abandoned.

The first question that occurred to me is to wonder why and whether a critique of these two theories of human nature–one based (however loosely) on evolutionary theory, the other based on economics–belong in the same book. Well, thinking about it, there is an explanation of sort: Both theories enjoy a fairly significant academic following; both appeal to “science;” and for Dupre, arguably, both theories have political or policy implications. In his mind, these policy implications are conservative; and one suspects ultimately that is what lead him to lump the theories together in one book–he dislikes what he sees as the policy implications of both.

But at least at the beginning, the theories he targets are dissimilar enough that he critiques them separately. Evolutionary psychology first. This theory is a sort of psychological companion to evolutionary biology. It postulates many aspects of human nature that continue to affect our lives today evolved in the Stone Age.

Dupre starts with a critique of reductionism. This is familiar ground to those who have read much philosophy of Mind or Science: Paul and Patty Churchland; mind/body dualism; set theory and its limits. Is what the word “donkey” really means just the set of all actual donkeys? How does one know what gets into the set? Must the word “unicorn” then refer to the set of all actual unicorns? And intensional states (belief, thinking, and so on). Dupre doesn’t go over all of this ground, though; he only needs to make the point that there are more options than reductionism and mind/body dualism. Fine.

Except that unless evolutionary psychology is a reductionist argument–that is, that its proponents want it to be a complete theory of human behavior at the individual level–the case for or against reductionism seems to me to be beside the point. And evolutionary psychology as I am familiar with it is *not* trying to be all that complete. Dupre needed to come up with a few examples of the more ambitious evolutionary psychologists to give what he does any weight.

His next argument against evolutionary psychology is that it is largely an empty suit. The response of the evolutionary psychologist to any observed behavior is to propose an evolutionary explanation that affects our mental capabilities to this day. Men and women court one another for evolutionary reasons; so some evolutionary psychologists have also proposed an evolutionary explanation for rape. Less controversially, parents tend to favor their own offspring; men tend to be more violent than women, and so on. But this theory doesn’t really explain actual individual instances of the behavior in the present or deviations from it; nor does it have any predictive power. When it gets down to it, one needs to know a good bit more about cultural factors; institutions, the immediate environment, and so on. He also notes that the theory leaves much unexplained–homosexuality being his choice of example (though how he knows that there is no evolutionary explanation for homosexuality a priori, I cannot imagine; there may very well be one, especially as it is common to many species).

While I agree with aspects of this critique, I don’t think that it is as devastating as he hopes. His point that theory can be an empty suit unless there is a way to test and prove or disprove its hypotheses is well taken. But my expectations of a general theory of human behavior don’t lead me to expect that it will have much predictive power in individual cases or complete predictive power; we are too complex. I expect that most evolutionary psychologists would readily concede that. And it doesn’t seem to me that the cultural explanations have more predictive power as a general matter, either. Each theory has its own sphere in which it has more or less. An evolutionary psychologist would note that most violence against children is perpretrated by stepfathers against stepchildren. The trend is likely to continue into the future. In the United States, spaghetti is usually eaten with a fork. This trend is also likely to continue in the future. Evolutionary factors contribute perhaps more to the former than to the latter; cultural factors more to the latter than to the former. Neither one has much to say about individual cases or deviations from the pattern. Of course not… these are general theories. The general theory of epidemiology has much to say about how quickly a certain flu might spread through the population, but much less power to predict the outcome of individual instances of exposure.

Ultimately, Dupre’s concern is that evolutionary psychology could be used as a pseudo-scientific basis for policy. Unfortunately, he doesn’t have an actual example of anyone doing this. Furthermore how it could have that tendency given that he thinks it is an empty suit is a little difficult to see. And the example he constructs as a hypothetical, that people who think of rape as an evolutionary strategy are likely to respond to it as if it were more justifiable, strikes me as unlikely. Acknowledging that our sinuses evolved with the drains located where they ought to be if we were an animal that walked on all fours doesn’t mean that one is more likely to view sinusitis as a good thing.

He next proposes explanations for human behavior more based on culture–and points out that culture evolves much more quickly than genetic material. Again, though, I don’t suppose there is much more in what he says that an evolutionary psychologist would disagree with. (Furthermore I am 80% without looking it up that he is getting the science wrong. The reason he gives for evolutionary theorists’ focus on the Stone Age is that genes evolve very slowly… but as I understand it the Stone Age comes into focus because it was the last period of time in which the population was low enough for significant genetic evolution to take place; in very large populations, mutations for good or ill just get swamped. It doesn’t have much to do with genes evolving slowly or quickly.)

Last but not least throughout he seems to want to distinguish evolutionary psychology (as a bad theory) from evolutionary biology (a good theory); but I am not so sure that is all that easily done, even for non-reductionists. Some stuff (organs) pretty clearly belong to biology; but what about pain? mating behavior? etc. The bottom line is that he does not touch the underlying draw of evolutionary psychology–that sense that there is something about human beings that remains as a defining factor over time–despite outlying examples and cultural veneers and remarkable diversity. But he is quite right that the theory lacks anything remotely resembling rigor.

And then he comes to economic theories of human nature. 1) He’s gotten hold of theories of perfect competition, and thinks that that is all very well and good, but as soon as one gets to the real economy, then of course it all goes to hell. He seems concludes from this that if markets are not perfect, they are no good at all and it is back to square one on policy… which does not in fact follow. First mistake. 2) Then he notes that the premise that people act rationally in their self-interest won’t do as a theory of human nature; if one takes this to mean that a person is likely to do what seems to him to be the best option at the time he does it, the theory is largely empty. So he assumes that postulating rationally self-interested behavior must go along with some kind of theory about the things that people are likely to want to do and value. Mistake number two. In fact, the theory of rational self-interest does not incorporate any such additional input about values or preferences. It is perfectly happy being empty… each individual’s well-being is then defined by his own set of preferences chosen by him, not by someone else. It isn’t a theory of human nature at all. It isn’t supposed to be. It is an uncontroversial premise used to learn other things about human behavior.

He has one nice observation in there. He notes that economists are likely to spin out long mathemetical proofs of things based on assumptions about people that are hopelessly simplistic–that all firms sell exactly the same product, that all people have the same information, that there are only two firms in the market, etc. etc. and then propose policy based on these unreal models. This is indeed a fair point. One might add that this nonsense occurs just as often in support of left-liberal projects as conservative ones.

Bottom line: we have another critique of the supposed foundations of “conservatism” by someone well qualified to undertake it, but not overly familiar with it; and evidently not on reasonably good terms with a single exponent of the theories that he critiques, such that he could do a reality check of his loose impressions of the theories. I wonder if there is an evolutionary explanation, or a cultural one?

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