If your question is featured here, we will send you a free copy of the new book from Bethany House Publishers, The Death of Truth . Let's first clarify what we're talking about with presuppositions and paradigms. It's something that seems so obviously true to us and so important to our other beliefs that we accept it as self-evident. An example of a presupposition is belief in God. Of course, belief in God also provides a basis for many other beliefs, like in areas of morality, life's purpose and so on.
Presuppositions are the basis for our world view.
That does not imply, of course, that presuppositions are beyond rational scrutiny. It's a model of what reality is. According to postmodernists, all we can do is construct models or paradigms of reality because reality is not objectively knowable. Paradigms include world views, or a set of presuppositions defined within a given culture. The paradigm sets its own rules for what's true and rational.