Kaj_Sotala comments on MIRI's Approach - Less Wrong
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Comments (59)
Thanks for the reply, Jacob! You make some good points.
I endorse eli_sennesh's response to this part :-)
I am not under the impression that there are "exact solutions" available, here. For example, in the case of "building world-models," you can't even get "exact" solutions using AIXI (which does Bayesian inference using a simplicity prior in order to guess what the environment looks like; and can never figure it out exactly). And this is in the simplified setting where AIXI is large enough to contain all possible environments! We, by contrast, need to understand algorithms which allow you to build a world model of the world that you're inside of; exact solutions are clearly off the table (and, as eli_sennesh notes, huge amounts of statistical modeling are on it instead).
I would readily accept a statistical-modeling-heavy answer to the question of "but how do you build multi-level world-models from percepts, in principle?"; and indeed, I'd be astonished if you avoided it.
Perhaps you read "we need to know how to do X in principle before we do it in practice" as "we need a perfect algorithm that gives you bit-exact solutions to X"? That's an understandable reading; my apologies. Let me assure you again that we're not under the illusion you can get bit-exact solutions to most of the problems we're working on.
Hmm. If you have lots and lots of computing power, you can always just... not use it. It's not clear to me how additional computing power can make the problem harder -- at worst, it can make the problem no easier. I agree, though, that algorithms for modeling the world from the inside can't just extrapolate arbitrarily, on pain of exponential complexity; so whatever it takes to build and use multi-level world-models, it can't be that.
Perhaps the point where we disagree is that you think these hurdles suggest that figuring out how to do things we can't yet do in principle is hopeless, whereas I'm under the impression that these shortcomings highlight places where we're still confused?
Additional computing power might not make the problem literally harder, but the assumption of limitless computing power might direct your attention towards wrong parts of the search space.
For example, I suspect that the whole question about multilevel world-models might be something that arises from conceptualizing intelligence as something like AIXI, which implicitly assumes that there's only one true model of the world. It can do this because it has infinite computing power and can just replace its high-level representation of the world with one where all high-level predictions are derived from the basic atom-level interactions, something that would be intractable for any real-world system to do. Instead real-world systems will need to flexibly switch between different kinds of models depending on the needs of the situation, and use lower-level models in situations where the extra precision is worth the expense of extra computing time. Furthermore, those lower-level models will have been defined in terms of what furthers the system's goals, as defined on the higher-levels: it will pay preferential attention to those features of the lower-level model that allow it to further its higher-level goals.
In the AIXI framing, the question of multilevel world-models is "what happens when the AI realizes that the true world model doesn't contain carbon atoms as an ontological primitive". In the resource-limited framing, that whole question isn't even coherent, because the system has no such thing as a single true world-model. Instead the resource-limited version of how to get multilevel world-models to work is something like "how to reliably ensure that the AI will create a set of world models in which the appropriate configuration of subatomic objects in the subatomic model gets mapped to the concept of carbon atoms in the higher-level model, while the AI's utility function continues to evaluate outcomes in terms of this concept regardless of whether it's using the lower- or higher-level representation of it".
As an aside, this reframed version seems like the kind of question that you would need to solve in order to have any kind of AGI in the first place, and one which experimental machine learning work would seem the best suited for, so I'd assume it to get naturally solved by AGI researchers even if they weren't directly concerned with AI risk.
+1