In other words, when I say “what’s the evidence for that?”, it’s not that I don’t trust your rationality (although of course I don’t trust your rationality either), but I just can’t deduce what evidence you must have observed from your probability declaration alone even if you were fully rational.
The argument can even be made more general than that: under many circumstances, it is cheaper for us to discuss the evidence we have than it is for us to try to deduce it from our respective probability estimates.
The argument can even be made more general than that: under many circumstances, it is cheaper for us to discuss the evidence we have than it is for us to try to deduce it from our respective probability estimates.