Friday, October 02, 2009
On various kinds of purpose
There are I think four different ideas that we might be implying when we talk about the purpose for something. One of them is an intended purpose. The purpose of X is Y because the one who made X intended it to do Y. If we believe in God, we probably believe in this kind of a purpose for ourselves. The second is natural purpose, so that the nature of something drives it toward a certain goal. We are sometimes told that the purpose of sex is reproduction, because that is its natural consequence. Thirdly, there is a chosen purpose. I choose to pursue the goal of becoming and airline pilot of a concert pianist because that is what I want to become. Finally, there is Darwinian purpose. If you believe in evolution, you believe that creatures have certain characteristics because those characteristcs helped them survive and pass on their genes. So a thoroughgoing Darwinian will say that the purpose of your eyes is to see, not because someone planned them so you could see, but because creatures who developed eyes had better awareness of the environment than the creatures they were competing with, and this resulted in those creatures surviving.