Evolutionary Explanations 3

I have been thinking more about the concept of play in animals.  I wrote this in a recent post:

The rabbits in my backyard sometimes leap at each other and seem to dance.  This may have some adaptive function, but it looks like simple fun.  A cat toying with a mouse is another example.  Good training for hunting, most likely; but a lot more fun for the one than the other.

Modern biology follows Aristotle’s lead in carefully distinguishing the explanations we offer in response to why questions.  If I am interpreting the behavior of the rabbits correctly, it is easy to answer the question “why do they behave this way?”  Because it’s fun.  In the case of the cat playing with a mouse, this seems almost certain.  Letting the mouse go and catching it again, over and over, isn’t something the predator does because it’s hungry.  Letting it go would risk losing a food resource, something the cat can afford because it is well fed.  It is playing for the sheer joy of it. 

Evolutionary explanations need be deployed when we ask a very different why question.  Why are these activities fun?  Here again the cat example seems unambiguous.  The animal is in training.  In the case of rabbits, I can only guess.  It didn’t look like mating behavior and I have no idea what the sex of the players was.  It probably has some social function, but I don’t know anything about social behavior among hares.  Almost certainly it has some evolutionary roots because I assume that what animals like always have such roots.  Why do we like vibrant colors?  The coevolution of herbivores and oranges explains that.  Why do we like the smell of cooking meats? 

The distinction between the evolutionary origins of our likes and dislikes and the motives for our actions is a very powerful one and it helps avoid one of the most frequent confusions when thinking about Darwinian explanations.  To say that my love for my wife and my children is an expression of adaptive dispositions is often interpreted to mean that my motives aren’t genuine.  What I really want is to get my genes into the next generation.  Even Ernst Mayr, one of the geniuses of the philosophy of biology, was guilty of this.  When a bird pretends to be injured in order to lead a predator away from her offspring, this is ultimately selfish.  She is promoting her own reproductive success. 

This is nonsense.  Were I not descended from a very long line of sexually reproducing animals, I would be very unlikely to be capable of any kind of love.  Because I am so descended, I am capable of such motives.  The latter serve their evolutionary purpose so effectively precisely because they are genuine.  Whatever I was thinking about when I invited a young lady to a James Taylor concert, several decades ago, it wasn’t genetics.  When I tenderly cradled my infant son and daughter in my arms for the first time, I was acting entirely out of love. 

Evolutionary biology is not reductionist.  It is expansionist.  It interprets human and non-human behaviors by reference to a number of robust dimensions, none of which can be reduced to the others.  Those dimension include psychology and physiology, neurons and neurosis.  Some of those dimensions extend backward into the deep past.  Rabbits breed like rabbits and that is why there are so many of them.  This afternoon in my back yard they were just having a rocking good time.