The idea of a difference, then, presupposes an order of things. A difference is only observed through rupture of an order. It is this question that underlies the social constructionist claim that differences are social constructs. This claim must be modified, however, in order to avoid tautology. Everything in society is socially constructed.
Differences are specific ruptures of a given spatio-temporal order.
That is to say, specific criteria of order must be first laid out in order to construct differences. For example, the categories women, Jews, homosexuals, and persons of color are constructed out of a perception that men, Gentiles, heterosexuals, and white people represent prototypical patterns. It is the observation of a deviation from these patterns that produces the others. The homosexual is someone who has different sexual preferences from a heterosexual. Black people are persons who differ from white people.