You don't have to believe in "mysticism" or "idealism" to know that consciousness exists.
I never said, nor implied, that consciousness doesn't exist. Your comment seems to be based on this mistaken idea. I also want to point out that I used Idealism in the philosophical sense in which it is the opposite of Materialism, not in the sense of being starry-eyed.
Cartesian dualism might produce unhelpful consequences , but you can't handwave it away simply by saying there's no such thing as mind or consciousness.
The problem with dualism is that mind and body need to be able to interact in some manner. In order for that to happen we have to posit a mechanism for that phenomenon. Until such a mechanism is discovered, or in some other way found to be necessary, then Occam's razor says to ignore it. (Note, that doesn't strictly mean that it doesn't exist, just that you don't posit something you don't need.) Additionally, I never said that there is no consciousness. I said that the question of "Does consciousness cause the brain" is not an interesting question.
If consciousness can't be explained by pure materialism, then pure materialism is an incomplete theory.
This is question begging.
As for the rest of your comment: Positing a spirit/consciousness that exists separate from (and prior to) the material body is magical thinking in exactly the same way as talking about gods and souls and we can write that off as imaginary. The experience that we have of consciousness is not separate from nor prior to the material body. In fact, my experience of consciousness began some years after my experience of body; which is to say that in my earliest memories (experiences of consciousness) I know that I already had a body.