Simplicity Priors are Tautological
Any non-uniform prior inherently encodes a bias toward simplicity. This isn’t an additional assumption we need to make—it falls directly out of the mathematics.
For any hypothesis h, the information content is $I(h) = -\log(P(h))$, which means probability and complexity have an exponential relationship: $P(h) = e^{-I(h)}$
This demonstrates that simpler hypotheses (those with lower information content) are automatically assigned higher probabilities. The exponential relationship creates a strong bias toward simplicity without requiring any special mechanisms.
The “simplicity prior” is essentially tautological—more probable things are simple by definition.
I first heard this idea from Joscha Bach, and it is my favorite explanation of free will. I have not heard it called as a ‘predictive-generative gap’ before though, which is very well formulated imo