“In fact it seems that there may be not one but two basic dichotomies : on the one hand similitude and difference, on the other hands solidarity and opposition. The "indifference" is ultimately a form of opposition.

At the pre-oedipien state, when there is acquired the distinction of the self and the other, similitude is a sign of belonging to a single class, an extension of the self, and difference is a sign of exteriority, of separation.
With the oedipien state the homology is reversed: difference of sex signifies complementarity and desire, whereas identity of sex entails identity of object of desire, rivalry, conflict”