But if you really think that there is NO reason at all that you might have accurate beliefs on a given topic, it seems to me that you do not have beliefs about that topic at all.
This doesn’t seem true to me.
First, you need to assign probabilities in order to coherently make decisions under uncertainty, even if the probabilities are totally made up. It’s not because the probabilities are informative, it’s because if your decisions can’t be justified by any probability distribution, then you’re leaving money on the table somewhere with respect to your own preferences.
Second, recursive justification must hit bottom somewhere. At some point you have to assume something if you’re going to prove anything. So, there has to be a base of beliefs which you can’t provide justification for without relying on those beliefs themselves.
Perhaps you didn’t mean to exclude circular justification, so the recursive-justification-hits-bottom thing doesn’t contradict what you were saying. However, I think the first point stands; you sometimes want beliefs (any beliefs at all!) as opposed to no beliefs, even when there is no reason to expect their accuracy.
I certainly didn’t mean to exclude circular justification: we know that evolution is true because of the empirical and theoretical evidence, which relies on us being able to trust our senses and reasoning, and the reason we can mostly trust our senses and reasoning is because evolution puts some pressure on organisms to have good senses and reasoning.
Maybe what you are saying is useful for an AI but for humans I think the concept of “I don’t have a belief about that” is more useful than making up a number with absolutely no justification just so that you won’t get Dutch booked. I think evolution deals with Dutch books in other ways (like making us reluctant to gamble) and so it’s not necessary to deal with that issue explicitly most of the time.
I agree. The concept of “belief” comes apart into different notions in such cases; like, we might explicitly say “I don’t have a belief about that” and we might internally be unable to summon any arguments one way or another, but we might find ourselves making decisions nonetheless.
I do think this is somewhat relevant for humans rather than only AI, though. If we find ourselves paralyzed and unable to act because we are unable to form a belief, we will end up doing nothing, which in many cases will be worse that things we would have done had we assigned any probability at all. Needing to make decisions is a more powerful justification for needing probabilities than Dutch books are.