The idea is, however we define P, how can we be that sure that there isn’t some kind of uncomputable physics that would allow someone to build a device that can find the lexicographically least object x such that P(x) < 1/3^^^3 and present it us?
Maybe we should just work off of the assumption that there’s no relevant uncomputable physics, because if there were, we should probably give up our endeavors anyways, unless we knew how to model an uncomputable reality within a computable AGI-program. As Schmidhuber ever so aptly wrote on his homepage:
The distribution should at least be computable in the limit. That is, there should exist a program that takes as an input any beginning of the universe history as well as a next possible event, and produces an output converging on the conditional probability of the event. If there were no such program we could not even formally specify our universe, leave alone writing reasonable scientific papers about it.
unless we knew how to model an uncomputable reality within a computable AGI-program
You could start out by trying to understand how an AI might invent the concept of uncomputability, and how it might then proceed to the possibility of uncomputable physics. And one way to get started here is by thinking as a cognitive historian, and asking how humans came up with the concept of uncomputability.
That gives you a probability inversely proportional to the integral of e^-(the description length) of each number from 0 to infinity. Complexity grows like log(n)-ish. It’s an improper prior.
So I agree with Adele that this may be a modus tollens / modus ponens moment.
If there’s some uncomputable physics that would allow someone to build such a device, we ought to redefine what we mean by computable to include whatever the device outputs. After all, said device falsifies the Church-Turing thesis, which forms the basis for our definition of “computable”.
The idea is, however we define P, how can we be that sure that there isn’t some kind of uncomputable physics that would allow someone to build a device that can find the lexicographically least object x such that P(x) < 1/3^^^3 and present it us?
Maybe we should just work off of the assumption that there’s no relevant uncomputable physics, because if there were, we should probably give up our endeavors anyways, unless we knew how to model an uncomputable reality within a computable AGI-program. As Schmidhuber ever so aptly wrote on his homepage:
You could start out by trying to understand how an AI might invent the concept of uncomputability, and how it might then proceed to the possibility of uncomputable physics. And one way to get started here is by thinking as a cognitive historian, and asking how humans came up with the concept of uncomputability.
“Give up” is neither a well-defined strategy, nor one that was shown to be preferable to its alternatives.
That gives you a probability inversely proportional to the integral of e^-(the description length) of each number from 0 to infinity. Complexity grows like log(n)-ish. It’s an improper prior.
So I agree with Adele that this may be a modus tollens / modus ponens moment.
If there’s some uncomputable physics that would allow someone to build such a device, we ought to redefine what we mean by computable to include whatever the device outputs. After all, said device falsifies the Church-Turing thesis, which forms the basis for our definition of “computable”.