Before a computer is assembled, it's a pile of useless wires and hardware. Put it all together and the whole is much greater than its parts, in that it can do things like beat the best chess player in the world. Conversely with the human brain, severe enough head injuries can cause profound changes in personality. Doesn't this "whole much greater than the sum of parts" not prove that dualism fails Occam's razor? I mean, if there was a soul independent of brain matter, where does it go after severe head injuries? By all accounts, people are not who they used to be after such unfortunate losses.