I think you’re asking too much of evolutionary theory here. Human bodies do lots of things that aren’t longterm adaptive—for example, if you stab them hard enough, all the blood falls out and they die. One could interpret the subsequent shock, anemia, etc. as having some fitness-enhancing purpose, but really the whole thing is a hard-to-fix bug in body design: if there were mutant humans whose blood more reliably stayed inside them, their mutation would quickly reach fixation in the early ancestral environment.
We understand blood and wound healing well enough to know that no such mutation can exist: there aren’t any small, incrementally-beneficial changes which can produce that result. In the same way, it shouldn’t be confusing that depression is maladaptive; you should only be confused if it’s both maladaptive and easy to improve on. Intuitively it feels like it should be—just pick different policies—but that intuition isn’t rooted in fine-grained understanding of the brain and you shouldn’t let it affect your beliefs.
I think you’re asking too much of evolutionary theory here. Human bodies do lots of things that aren’t longterm adaptive—for example, if you stab them hard enough, all the blood falls out and they die. One could interpret the subsequent shock, anemia, etc. as having some fitness-enhancing purpose, but really the whole thing is a hard-to-fix bug in body design: if there were mutant humans whose blood more reliably stayed inside them, their mutation would quickly reach fixation in the early ancestral environment.
We understand blood and wound healing well enough to know that no such mutation can exist: there aren’t any small, incrementally-beneficial changes which can produce that result. In the same way, it shouldn’t be confusing that depression is maladaptive; you should only be confused if it’s both maladaptive and easy to improve on. Intuitively it feels like it should be—just pick different policies—but that intuition isn’t rooted in fine-grained understanding of the brain and you shouldn’t let it affect your beliefs.