Can Cartesian Dualism successfully account for the existence of consciousness?
Answer by Danny Krämer
I think, Cartesian Dualism makes consciousness even more mysterious than materialism. As you know, Descartes postulates two different substances. The res extensa is the substance of all extended bodies. The res cogitans is the substance of the thinking beings. This substance is not in space because it is not extended. The biggest problems are: First, how is it that a special (bit of) res cogitans (me) is bound to a specific piece of res extensa (my body)? You can only explain this by some supernatural story. Second, how can these two substances interact? When I think that I want to raise my arm (something the res cogitans that is me does) then I can ‘command’ my body to raise the arm. But how is that even possible if the res cogitans has no spacial extension? The res extensa is a closed system, as we know from physics. You can not get any energy in that was not there before. Descartes said, the soul steers the direction of the pineal gland and so the direction of the spirits. But that is also impossible as Leibniz pointed out. Not only the energy of a physical system is constant but also the impulse. There is in principle no way to understand how to make dualism a working hypothesis.
On the other hand it is very plausible that materialism in some form could be true. We see that our brain has a deep connection to our consciousness. We can do experiments to get a better understanding of the connection between brain and mind. Something that is just impossible in a cartesian picture. Even so we do not understand the complexities yet, it is at least imaginable that a materialist view of the mind could be well established some day.