Memories: Brain vs Soul

Question from Marie-Denise:
If memories and thoughts completely come from one’s brain and not from a person’s soul, then why do we keep our memories even though we know every cell in one’s brain is regenerated every few years? Thanks.

Answer by SmartLX:
Quite simply, they’re passed on.

Memories are stored in the brain as electrical patterns, which don’t reside in individual cells but travel around certain areas of the brain as needed, for instance when you’re figuring out where you left your keys. If a brain cell dies while hosting part of a memory, that part can often be recreated by the rest of the brain, or else there’s another copy in there somewhere, so the impact on your overall memory is minimal. (Daniel Dennett is fond of saying, “Every time you read it or say it, you make another copy in your brain.” He then repeats this twice.)

Actually, brain cells aren’t replaced like the other cells in the body. Glial cells are, but the all-important neurons hardly regenerate at all. Therefore maintenance of memory is not really a matter of tagteaming from old cells to new cells, but rather a process of shuffling between existing cells. The brain is only too happy to do this, because it’s by transferring memories and other thoughts from cell to cell that we “think” about them.

The idea that the soul is the source of certain thoughts carries its own conundrums, chiefly the fact that every known mental process can be permanently impaired or completely disabled by sufficient brain damage. If an ethereal soul is solely responsible for any observable function, that function should be impervious to physical injury, and this has never been observed. If instead the brain functions as a conduit for every “action” of the soul, there is no evidence for the existence of an independent soul. Don’t feel put-upon though – believers in an incorporeal “mind” independent of the brain have the same kinds of problems when justifying their view, so this is not purely a matter of theology.