I don't think randomness exists. The post that I'm currently writing is definitely not a random post, but even if I were to make a post divorced from all causal connection from what was discussed on this forum, there would still be a kind of internal logic to me that governed what it was that I was planning to say. It's just not something any of you would have privileged access to, in the same way I do.
I think people can have degrees of belief in something, deployed in the presence of partial information problems. I also think it's true that our current best physical theories are approached from the epistemic, information-first perspective, and that as a result the closest way we have of predicting what is going to happen is statistical, rather than deterministic.
But to say that there's a kind of fundamental randomness, as opposed to simply cases of potentially unavoidable lack of knowledge, I'm not entirely clear as to how to interpret that. Any such randomness, it seems to me, would only be needed as a theoretical postulate in a level of analysis beyond that used in active scientific or mathematical investigation.