If we believe that the mind is generated from the brain, then we should be able to explain the mind at least in the causal respect through brain activities. However, the difficulty of clearly expressing experiences, Davidson's argument and the problem of free will show that this kind of causal reduction cannot be done. Based on this irreducibility, I also argue that conceptual frameworks of the mental and the physical are both mistaken because (1) they are not coherent, and (2) present physical conceptual framework cannot explain free will, thus this conceptual framework cannot be applied to unify the mind and the brain, and (3) the conceptual framework of the mental is hard to causally explain the physical which is mainly structured through necessary and sufficient conditions.
