EDIT: This post applies if deterministic computing is assumed, but not if nondeterministic computing is assumed. Solomonoff induction itself is agnostic in that regard. It doesn’t prescribe any particular paradigm of computation.
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According to Solomonoff induction, the probability that solipsism is not true is zero.
When applying Solomonoff induction, the entirety of the probability mass is distributed between world models which are one-dimensional sequences of states where every state has precisely one successor, the only possible exception being the last episode of the sequence, if the sequence ever ends (a condition which incidentally always makes the sequence more complex, making some kind of solipsistic afterlife quite probable).
Does this mean that we should modify Solomonoff induction, or could it perhaps - just perhaps - mean that there is no we after all?
Solomonoff indiction doesn’t say anything about larger world models that contain the one-dimensional sequences that form the Solomonoff distribution. You appear to be saying that although the predicted sequence is always solipsistic from the point of view of the inductor, there can be a larger reality that contains that sequence, but that is an extra add-on that doesn’t appear anywhere in the original Solomonoff induction.