3 ms·
I'm going to go into my own perspective of it; it is not reflective of what it discusses. The linked multimedia article gives a narrative of intelligent system
by jhanschoo 1y ago
I'm going to go into my own perspective of it; it is not reflective of what it discusses.
The linked multimedia article gives a narrative of intelligent systems, but Hutter and AIXI give a (noncomputable) definition of an ideal intelligent agent. The book situates the definitions in a reinforcement learning setting, but the core idea is succinctly expressed in a supervised learning setting.
The idea is this: given a dataset with yes/no labels (and no repeats in the features), and a commonsense encoding of turing machines as a binary string, the ideal map from input to probability distribution model is defined by
1. taking all turing machines that decide the input space and agree with the labels of the training set, and
2. the inference algorithm is that on new input, the output is exactly the distribution by counting all such machines that assent vs. reject the input, with their mass being weighted by the reciprocal of 2 to the power of the length, then the weighted counts normalized. This is of course a noncomputable algorithm.
The intuition is that if a simply-patterned function from input to output exists in the training set, then there is a simply/shortly described turing machine that captures that function, and so that machine's opinion on the new input is given a lot of weight. But there exist plausible more complex patterns, and we also consider them.
What I like about this abstract definition is that it is not in reference to "human intelligence" or "animal intelligence" or some other anthropic or biological notion. Rather, you can use these ideas anytime you isolate a notion of agent from an environment/data, and want to evaluate how the agent interacts/predicts intelligently against novel input from the environment/data, under the limited input that it has. It is a precise formalization of inductive thinking / Occam's razor.
Another thing I like about this is that it gives theoretical justification for the double-descent phenomenon. It is a (noncomputable) algorithm to give the best predictor, but it is defined in reference to the largest hypothesis space (all turing machines that decide on the input space). It suggests that whereas prior ML methods got better results with architectures that are carefully designed to make bad predictors unrepresentable, it is also not idle, if you have a lot of computational resources, to have an architecture that defines an expressive hypothesis space, and instead softly prioritizing simpler hypotheses through the learning algorithms (e.g. an approximation of which is regularization). This allows your model to learn complex patterns defined by the data that you did not anticipate, if that evidence in the data justifies it, whereas a small, biased hypothesis space would not be able to represent such a pattern if not anticipated but significant.
Note that under this definition, you might want to talk about a situation where the observations are noisy but you want to learn the trend of it without the noise. You can adapt the definition to be over noisy input by for example accompanying each input with distinct sequence numbers or random salts, then consider the marginal distribution for numbers/salts not in the training set (there are some technical issues of convergence, but the general approach is feasible), and this models the noise distribution as well.
- causal 1y ago> I'm going to go into my own perspective of it; it is not reflective of what it discusses Why not answer the question? And looking at your paragraphs I'm still not sure I see a definition of intelligence. Unless you just mean that intelligence is something that can approximate this algorithm?
- jhanschoo 1y agoOne way you can define intelligence considered functionally is how an entity given patterned input can demonstrate that it learns and understands that pattern by responding with an extension of that pattern. This definition defines what an ideally intelligent entity is if we use this functional definition.
- mxkopy 1y agoAre ”noisy” inputs here at all related to ones where their Kolmogorov complexity is their encoding length? I don’t know how much I buy the idea that intelligence maximizes parsimony. Certainly true for inductive reasoning but I feel like there’s some tradeoff here. There are probably cases where a small TM explains a very large but finite set of observations, but if a few new ones are added the parsimonious explanation becomes much longer and looks much different from the previous one. I know this wouldn’t be under the same assumptions as the book though :p
- jhanschoo 1y agoIf we accept the functional framing (as being able to give a suitable suggestion conditioned on input), then it seems to me that parsimony is the only sensible general framing; every deviation from that is something that is specific to an application or another and can be modeled by a transformation of the input space/output space. > There are probably cases where a small TM explains a very large but finite set of observations, but if a few new ones are added the parsimonious explanation becomes much longer and looks much different from the previous one. Indeed, to use an analogy, if you have 99 points that can be described perfectly by a linear function except for one outlier, then clearly your input isn't as clear-cut as might have been originally assumed. On the other hand, you may be in a different setting where you have noisy sensor inputs and you expect some noise, and are looking for a regression that tolerates some noise. In such a situation, only when the stars align perfectly would your input data be perfectly described by a linear function, and we just have to accept that a broken watch is perfectly right twice a day whereas a working one is almost always only approximately right, but all the time.