Sunday, April 29, 2007 A Fallacy in Brain Science

Recently, while reiterating in a new context the classical discussion concerning the nature of altruism, that is, whether we humans actually do things for other people or whether our motives are always selfish, someone submitted a comment which I believe contains a common fallacy among contemporary students of human nature.

The framework for the classical discussion is usually this: On the one hand, it is patently obvious that people do things for other people all the time. This is taken to the extreme – but extremes are allowable in discussions of this sort – when one is willing to die for someone else, which, on the surface anyway, offers little or no benefit to one's self. On the other hand, one always has an internal motive for acting for another, either to improve one's reputation, or to gain favors, or, because it just plain makes the person feels good to act for another. Even this good feeling is thought of as a selfish thing on this view. Furthermore, in a case where one is willing to die for another, it is, on this view, a result of the person calculating selfishly that death is preferable to living with guilt or shame or without another person etc. There are powerful and interesting arguments on both sides which may make interesting material for a future blogging.

Well, this time around, one of the discussants offered this argument from neuroscience/biopsychology. Altruism has been discovered in the brain, he claimed. There is a region in the brain that fires during altruistic acts, or that is better developed in altruistic people than in more selfish people, etc. This was submitted as evidence that true altruism does exist, since it has been physically discovered in the brain.

The fallacy is that the discovery of brain phenomena is no evidence one way or another for the existence of psychological or behavioral phenomena. Imagine that I get to observe a person for a week, with the limitation that I can only see that person's brain. I see section X of the brain fire in pattern Y. I would have absolutely no idea what the person is doing/thinking/feeling unless I have already linked that firing pattern with that non-neural activity (and probably even in such a case, but lets ignore that). Imagine then that I have only observed brains and never made those connections with non-neural states. It is clear that I would have no idea of the connection between the brain phenomena and "human" phenomena without also having observed the human activity. So in order to find altruism, or anything else of the sort, in the brain, I must already have in mind a certain class of human activity, must already have judged those things as altruistic, and only then can I make the link to brain activity. Once I have made these judgments, even before I find it in the brain, I already know the phenomenon exists, and the view from the brain merely offers me another perspective, indeed an informative one, on it. Conversely, if we judge that this activity is not altruistic, then the associated firing pattern in the brain must be judged not to be linked with altruism.

It is a common error in a common contemporary worldview to think that phenomena of human nature only exist if they can be found in the brain. If we start with the brain, as we have seen, we don't know what any of its phenomena mean unless we observe the associated body/mind phenomena. And if we start with the body/mind phenomena, then we don't need the brain phenomena to confirm their existence. Even if we have them, they prove nothing vis-à-vis the mind/body phenomena in question.