How else can you impartially wield Occam's Razor than with a formal model, and what convincing formalization is there other than Kolmogorov Complexity (and assorted variants), which SI in a way extends?
Setting aside the theoretical objections to Solomonoff induction (a priori assumption of computability of the hypotheses, disregard of logical depth, dependance on the details of the computational model, normalization issues), even if you accept it as a proper formalization of Occam's Razor, in order to apply it in a formal argument, you would have to perform an uncomputable calculation.
Since you can't do that, what's left of it?
r/HPMOR readers on heroic responsibility - not the OP, the comments. Holy snorkels this is good.