This community already hopefully accepts that one can learn from knowing other people's opinions without knowing their arguments; Aumann's agreement theorem, and so forth.
I don't think Aumann's agreement theorem has anything to do with taking people's opinions as evidence. Aumann's agreement theorem is about agents turning out to have been agreeing all along, given certain conditions, not about how to come to an agreement, or worse how to enforce agreement by responding to others' beliefs.
More generally (as in, not about this particular comment), the mentions of this theorem on LW seem to have degenerated into applause lights for "boo disagreement", having nothing to do with the theorem itself. It's easier to use the associated label, even if such usage would be incorrect, but one should resist the temptation.
People sometimes use "Aumann's agreement theorem" to mean "the idea that you should update on other people's opinions", and I agree this is inaccurate and it's not what I meant to say, but surely the theorem is a salient example that implicitly involves such updating. Should I have said Geanakoplos and Polemarchakis?
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