Modern philosophy, beginning with Descartes, raises issues of mind-body dualism, rationalism and empiricism, idealism and materialism. Yet most modern philosophers at least through Kant continued to believe in the basically Christian concept of an immortal, "pre-psychological" soul, presumeably subject to duties and divine judgment.
How did Descartes, for example, define the soul within his dualism of res extension and res cogitans? Is is a distinct "substance" or "property"? Is it continuous with the being of God and with other souls...or a discrete, isolated entity? How does the soul relate to mind and/or body? How does it transform physical or mental activities into a timeless moral account?
Did subsequent modern philosophers develop clear, systematic theories of the soul? Or did they tend to separate theological questions from their own work. Are there any aspects of such immaterial "pre-psychology" that retain a lasting interest?