"Perhaps the best way of seeing the reality, indeed the ubiquity in Nature, of reasons is to reflect on the different meanings of “why.”

The English word is equivocal, and the main ambiguity is marked by a familiar pair of substitute phrases: what for? and how come?”

“Why are you handing me your camera?” asks what are you doing this for?

“Why does ice float?” asks how come: what it is about the way ice forms that makes it lower density than liquid water?"

P48, From Bacteria to Bach, The Evolution of Minds by Dan Dennet