If evolution is driven by the survival of the individual, then it’s pretty hard to explain why anyone would sacrifice for anyone else, since any impulse to do so should have been bred out of us long ago. Theorists of “kin selection” propose a solution to the puzzle. Does it work?
According to this theory, the unit of natural selection isn’t the individual, but the gene. My close relatives share a lot of my genes, so in some cases the survival of the genes we share – in this case, the very genes for sacrificing for relatives -- is better promoted by my sacrificing for them than by my clinging to life at their expense.
Such explanations do have value. Kin selection explains some animal behaviors quite well. In the case of the social insects, it has been a spectacular success. But if kin selection is all there is to it, then why would I ever sacrifice for neighbors who aren’t close relatives, persons with whom the value of my coefficient of genetic relatedness is very small?
Evolutionary psychologists have an answer to this one too. I am able to sacrifice for non-relatives by viewing them as though they were my relatives. After all, don’t we say that all men are brothers? And don’t we call that saintly woman Mother Teresa?
Hold on a moment: The explanation doesn’t work. If the kin selection hypothesis is true, then although sacrifice for close kin is adaptive, sacrifice for unrelated people whom we merely think of as though they were close kin is maladaptive. On balance, it makes the survival of my genes less likely, not more. So by this hypothesis, even though we should be strongly motivated to sacrifice for real kin, we should be strongly averse to sacrificing for merely figurative ones.
We may concede that the impulse to sacrifice for non-kin is rather weak and unreliable. But it exists. Moreover, we applaud it and believe that we ought to cultivate it. On the kin selection hypothesis, not only should the impulse to sacrifice for non-kin not exist – not only should we have the opposite impulse – but we shouldn’t even think we ought to cultivate such a motive, for the inclination to think so would be maladaptive too. We should have evolved to think that we shouldn’t view all men as brothers.
So there are two possibilities.
1. Natural selection is the whole story, but we don’t yet have all of the pieces.
2. Natural selection isn’t the whole story.
The materialist will back hypothesis 1. He will do so on grounds of faith – and yes, it is a faith – that material nature is all there is, so that even if we don’t see how it could be, one day we will. I find a faith that is open to the possibility of additional, non-materialistic explanations much more persuasive and interesting. Follow the evidence where it leads.