Thanks for the reply. I would be interested in your longer reply, if you get the chance! I get where you're coming from now that you mention the microbiome. Th

Thanks for the reply. I would be interested in your longer reply, if you get the chance! I get where you're coming from now that you mention the microbiome. That similarly reminds me of headlines like "antidepressants alter the brain," specifically variations that imply something groundbreaking; on some level it IS impressive that physical effects can be observed, but on another, it's almost trivially true that it affects the brain, because where else do thoughts originate? In fact, speaking of depression, there's probably studies exactly like what you described where depression is X. I think this could be usefully tied back to the software/hardware distinction I raised. Some might say that, in a lot of cases, depression is due to faults in "software" -- negative thinking, assuming the worst, etc, -- or at least is better treated as though it were. This is opposed to faults in "hardware" -- insufficient production of serotonin, or whatever (and I'm sure there cases where this is the best explanation/treatment). So maybe a certain microbiome state is like a computer running on the Mars rover where its hardware is subjected to fault-inducing radiation? The software/hardware distinction probably isn't as clean in the brain compared to our silicon-based computers! We know so little in this area that it probably does make sense to proceed as though everything affects everything, as you say -- but I also think it's important to allow that it may not.