Mutualism and Egoism

Mutualism entails the voluntary participation in equitable exchange, and, hence, that fairness is freely pursued.  However, Prouhon does not supply a principle that would ground such behavior, so it can only be an object of speculation.  Now, there can be little doubt that the principle is neither Psychological nor Ethical Egoism, each of which excludes Fairness as an immediate conative aim.  An alternative possibilty, one consistent with optimistic concepts of Human Nature, is the thesis of an instinct for Justice, though proof of the existence of such an instinct would seem difficult to establish, since that would require study of behavior under conditions that are completely abstracted from historical vicissitudes.  Instead, a more accessible possibility is Dewey's thesis that human behavior is essentually plastic, from which it follows that Mutualist conduct is the product of education.  In any case, at minimum, Mutualism is antithetical to any of the prominent traditional varieties of Egoism.