Ockham's razor here isn't a "philosophical principle", it's math. AIXI is doing a shortest-first search for predictors that match the observed environment, exc

Ockham's razor here isn't a "philosophical principle", it's math. AIXI is doing a shortest-first search for predictors that match the observed environment, except that it's searching them all simultaneously in infinite parallel (that's why it's not computable) and what gets moved around is probability weighting. Ockham's razor describes the starting state of the weightings when there hasn't yet been any evidence: shorter predictors are given more weight.