Philosophical dualism has been with us for a long time. It’s one of the key components of Western thought: good and evil, masculine and feminine, subject and object, and the big one for this week’s program—mind and body. Nancey Murphy is a Christian philosopher who doesn’t believe in the soul. She’s a physicalist, which means she believes that 'the soul' is really just a by-product of neurobiology. But if all our rational decisions come down to brain impulses, where does that leave moral responsibility? And what kind of Christian doesn’t believe in the soul anyway?