Abstract. We view a human being as a mental and spiritual entity and also as having a physical nature. The essence of a person is revealed in our thinking about personal identity, quality of life, and personal responsibility. These conceptions do not fare well in a Cartesian or dualist picture of the person as there are deep problems with the idea that the mind is an inner realm. I argue that it is only as we see the thoughts, actions, and interactions of persons as necessarily involving physical entities in the world whose nature is not completely captured in scientific descriptions that we can understand our existence as mental and spiritual beings.