I just mean: “universality” in the sense of a UTM isn’t a sufficient property when defining the speed prior, the analogous property of the UTM is something more like: “You can run an arbitrary Turing machine without too much slowdown.” Of course that’s not possible, but it seems like you still want to be as close to that as possible (for the same reasons that you wanted universality at all).
I agree that it would be fine to sacrifice this property if it was helpful for safety.
I just mean: “universality” in the sense of a UTM isn’t a sufficient property when defining the speed prior, the analogous property of the UTM is something more like: “You can run an arbitrary Turing machine without too much slowdown.” Of course that’s not possible, but it seems like you still want to be as close to that as possible (for the same reasons that you wanted universality at all).
I agree that it would be fine to sacrifice this property if it was helpful for safety.