WitchitaBoy,

Wonderfully put and illustrated. I would add that the self interest hypothesis easily becomes circular once it is accepted, because self interest is then defined by behaviour, and the problem becomes trying to show that it *is* self interest. Put differently, the hypothesis is only useful if there is a list of things that can be considered as in ones self interest, *independent* of perception. Once perception enters the picture, self interest becomes a moving target and loses its explanatory power. It explains everything and nothing at the same time.