## LESSWRONGLW

Sure, but what computation do you then do, to figure out what UDT recommends? You have to have, written down, a specific prior which you evaluate everything with. That's the problem. As discussed in Embedded World Models, a Bayesian prior is not a very good object for an embedded agent's beliefs, due to realizability/grain-of-truth concerns; that is, specifically because a Bayesian prior needs to list all possibilities explicitly (to a greater degree than, e.g., logical induction).