Now, by "natural" I don't mean that we're all consciously solving constrained optimization problems all the time, to maximize our welfare. I'm thinking along more of the Matt Ridley, Origins of Virtue-line; that people are particularly good at trading and reciprocating compared to other beings and that as a consequence of our having those abilities, we got modern market economies.
Which makes me suspect that it is no accident that God gave us a world in which, as Adam Smith noted, "It is not from the benevolence of the butcher, the brewer, or the baker, that we can expect our dinner, but from their regard to their own interest." (See EconLib).