While the question is phrased in the form of a choice, the essence of the inquiry implies an opposition to one or the other’s point of view. For example, Rene Descartes, who championed Reason as the singular reliable epistemology (way of knowing) would be interesting for a pragmatist to meet, because they could agree on the basis of their mutual philosophies. But more interesting would be a discussion between Descartes and a Spiritualist, or a Transcendentalist. Such a conversation would elicit inquiries into the existence of things that did not submit to Reason, or physics, or scientific proof—mother love, fear, hope, a belief in an afterlife, etc. The first thing I would say to him is “I think I think; therefore I think I am.” This little statement punches a hole in his logic, and it would be interesting to hear his response. Another line of inquiry might be, “I am--OK, but why am I?” This might be called the existential rejoinder. Descartes may have opened an interesting line of inquiry, but later philosopher have gone beyond his thought. It would be fun to bring him up to date on Phenomenology, Speech Theory a la Wittgenstein, and Existentialism.