Specific matter theory of the mind
Specific matter theory of the mind's premise is that the exact same matter needs to be used to produce the same consciousness or mind; to produce the same you. We know through science that the matter that makes up your body now is not the same matter that your body was made up years ago. So your consciousness is not dependent on a specific group of matter. The theory will have to specify a specific grouping of matter at a specific time in your life. It also has to explain scientifically why such and such a grouping of matter at each specific time and not another grouping of matter. This means that specific atoms must have some property beyond their physical properties, that have not been found, to let this happen. Consequently, the specific matter theory of the mind is not scientific and can not be rationally used to prove that life after death is not possible.
An example of this argument is presented in the book "Immortality" by Paul Edwards, starting on page 292. It is interesting that he allows some form of dualism. If he did not, his argument would fall apart without even the using the problems with the premise of the specific matter theory of the mind.