and, Pete: "....if we are accidents of chemical processes, that would include your brain. why should we trust anything anyone says?"

Because, Pete, those chemical processes have similar, if not identical, foundations; and we can, with a little effort, learn what passes for rational human discourse. That is, we have ways to 'trust' a person's language and its meaning, whether we agree with them or not.

Is that what you were asking about, or did I miss the import? (It was a bit of a oblique question.)