We find ourselves in a paradigmatic transition which we may designate as a postmodern transition, and to account for its emancipatory potential adequately we need an appropriate postmodern theory that I call theory of oppositional postmodernism. According to this theory, it is possible and necessary to think of social regulation and emancipation beyond the limits imposed by the paradigm of modernity. To accomplish it, an oppositional postmodern theory of science and an oppositional postmodern theory of law are called for. This stance takes the promises of modernity very seriously, be they liberty, equality and fraternity. It submits them to a radical critique that allows us to understand the perversities concerning the fulfillment of some of the promises and the impossibility of fulfilling others and it allows us to identify the emancipatory potential that the promises keep intact but that can only be realized within postmodern social, cultural, political, epistemological, and theoretical boundaries. The promises of modernity have become problems for which there seems to be no solution at all. In the meantime, the conditions that brought about the crisis of modernity have not yet become the conditions to overcome the crisis beyond modernity. Hence the complexity of our transitional period: we are facing modern problems for which there are no modern solutions. The search for a postmodern solution is what I call oppositional postmodernism.