Comment by Xcelerate

I’m guessing your downvotes were for tone? You’re correct though regarding Solomonoff induction, as the choice of reference universal partial recursive function gives drastically different results for predictions based on finite data (even with access to a halting oracle). Asymptotically, any choice eventually converges to the same predictions, but that’s no help when there are infinitely many choices for U and no obvious natural prior over universal functions. And I don’t find the argument that our natural environment “implements some choice of U” particularly convincing. There’s definitely an open mystery there.