On the observation that changes in brain matter affect changes in thought, particularly reductionist atheists often claim that thought is a mere by-product of matter, but I find it interesting that proceeding by pure thought alone, I can willfully move my arm right now.
Doesn't it follow, then, that thought — i.e. consciousness — also causes matter to move? Or is the decision to move one's arm merely an illusory but incredibly well-timed forethought that somehow preceded the act? Provided we're not too shameless to deny accept the latter absurdity, doesn't the former observation suggest that perhaps thought is more than the mere by-product of matter?
It so happens that a single claim forms the entire foundation upon which nearly all varieties of theism must inevitably be built: the claim that consciousness can exist outside of a material body. Although the claim is a necessary component of nearly all religions, we should note that it is not necessarily theist, as there are atheists who accept the existence of metaphysical entities.
As far as traditional monotheistic religions (Judaism, Christianity, Islam or any derivative thereof) are concerned, we can safely say that if no spirits exist and consciousness cannot exist outside of a body, then their key claims are either false or severely distorted (Ephesians 6:12, Luke 3:22 & John 4:24, as examples).
Most skeptics and rationalists are familiar with the difficulty (note: not impossibility) of proving a negative. While it’s certainly difficult to prove the materialist’s claim that there is not a ghost in the machine, what’s less difficult and also theoretically possible is proving or at least supporting the claim that consciousness can and does exist outside physical bodies. Let’s refer to this claim as the immaterial consciousness hypothesis, or ICH for short [NOTE: the TMC introduced here envelopes the ICH. In other words, the ICH represents a deprecated term that has since been modified. I explain the reason for the change here, and I apologize for any confusion].