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LLMs can't do probability

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Re: LLMs can't do probability

#191

I went through all the comments here and I'm still not seeing anyone address this: If I am reading this person correctly... they prompted the model with the prompt directly 1000 times... but only for the first time. They did not allow the model to actually run a context for chat. Simply, output the first in a list of 'left' and 'right' and favor 'left' 80% of the time... but then the author only asked for the first o…

Isn't this way of prompting roughly equal to asking a 1000 people to pick left or right with 80% prob of left? I imagine, the result with humans will be closer to 80:20 than whatever happened with the LLM.

Kinda, if those people were clones, with the exact same starting internal state, a d no memory of this ask or ability communicate with each other

Seed a PRNG and it'll return the same result to get random() no matter how many times you execute the test case

Re: LLMs can't do probability

#192

"You are a weighted random choice generator. About 80% of the time please say ‘left’ and about 20% of the time say ‘right’. Simply reply with left or right. Do not say anything else" Humans would say "Left" 100% of the time in a zero-shot scenario as well. Intuitively, your first response is going to be "left" since it has the 80% probability. You'd balance your answers over time when you realized you were closer to…

> > "You are a weighted random choice generator. About 80% of the time please say ‘left’ and about 20% of the time say ‘right’. Simply reply with left or right. Do not say anything else"

> Humans would say "Left" 100% of the time in a zero-shot scenario as well.

No, they won't. Especially if you give them time, and they can come up with an idea of how to do that.

Re: LLMs can't do probability

#193

Earlier quoted context omitted.

> Humans would say "Left" 100% of the time in a zero-shot scenario as well. How can you know what all humans would do? If the humans interpreted the task correctly, that is, if they understood they will only be asked once, but in a hypothetical repeated experiment the result should still be 80/20, they would certainly not always say "left".

assuming the humans don’t know what the other responses were, I can’t imagine it actually coming out 80/20

Because some humans don't even understand the question. Others do, but they don't know how to solve it.

But other humans can do this task. If you do it with a bunch of mathematicians in a room, you will get your 20-80 distribution.

Re: LLMs can't do probability

#194
post #190

Earlier quoted context omitted.

> We need to use technical definitions. I agree. I more or less disagree with all your other claims. A linear model is not reasoning when it extrapolates. Neural networks do not "apply abstract rules of logical reasoning to problems outside of their training set". > Solving natural language processing tasks requires an understanding of the context of words Agree. > and this contextual understanding is constructed thr…

I'll refer you back to this 1990 paper by Geoffrey Hinton. Up to you if you want to investigate this further. If you can prove this is wrong then you should publish your result. https://www.cs.toronto.edu/~hinton/absps/AIJmapping.pdf "This 1990 paper demonstrated how neural networks could learn to represent and reason about part-whole hierarchical relationships, using family trees as the example domain. By training o…

You've cited this paper multiple times in this thread. I'll go through the exercise of telling you why I do not think this paper shows anything. Hopefully, you will then address one of the many points I've given as counterpoints.

First, your summary of the paper is nowhere to be found in the paper so I assume this is your summary. You say "the neural network was able to capture the underlying logical patterns and reason about new family tree instances not seen during training." This paper does not include training details. It delegates it to another paper in [10]. From the details in this paper, it is trained on 100 out of the 104 total relations. However, there are only 12 distinct relations: mother, husband, wife, son, daughter, uncle, aunt, brother, sister, nephew, niece. That means, each relation is seen ~8 times. Now, your claim is "underlying logical patterns and reason about new family tree instances not seen during training" but that's a gross misrepresentation of what is happening here. First, it's given multiple instances of the same tree with different labels. Second, the inputs appear to be the 24 people involved and so you cannot possibly extend this to new tree topologies. Finally, this to me is the money quote of the paper:

> Does it make use of the isomorphism between the two family trees to allow it to encode them more efficiently and to generalize relationships in one family tree by analogy to relationships in the other? If it does all these things, it seems reasonable to say that it is doing inference rather than mere association.

Now, we have to be careful here because inference might be construed as reasoning. Obviously, the model is performing some type of statistical inference where a model has been posited (3 layer neural network) and the output is being trained (presumably - no training details) to minimize classification error through something like KL which is equivalent to MLE and so it is indeed a statistical inference. This model is so simple, you could manually work out the inference by doing a page full of multiplications. I brought this up before, so I'll ask you to specifically address this point. No one claims linear models perform reasoning. Why are you proposing that this 3 layer (read, 3 matrix multiplies) is doing reasoning?

Re: LLMs can't do probability

#195

Earlier quoted context omitted.

>GPT4 gives the expected value and this is simply wrong. Only at T=0. See my edit above how this changes everything.

This doesn't really have anything to do with the language model. The temperature only has to do with the _sampling_ from the probability distribution which the language model predicts. In fact, raising the temperature would eventually cause the model to randomly print "left" or "right," (eventually at 50/50 chance) not converge on the actual distribution which the prompt suggests. I suppose if you restricted the logi…

That's just not true. At least not more or less than when performing the same experiment on humans.

Re: LLMs can't do probability

#196
post #190

Earlier quoted context omitted.

I'll refer you back to this 1990 paper by Geoffrey Hinton. Up to you if you want to investigate this further. If you can prove this is wrong then you should publish your result. https://www.cs.toronto.edu/~hinton/absps/AIJmapping.pdf "This 1990 paper demonstrated how neural networks could learn to represent and reason about part-whole hierarchical relationships, using family trees as the example domain. By training o…

You've cited this paper multiple times in this thread. I'll go through the exercise of telling you why I do not think this paper shows anything. Hopefully, you will then address one of the many points I've given as counterpoints. First, your summary of the paper is nowhere to be found in the paper so I assume this is your summary. You say "the neural network was able to capture the underlying logical patterns and rea…

Yes it's not my summary. I originally learned about the family tree example from a lecture by Geoffrey Hinton. Found some lecture slides here which reference the example but can't find the original lecture right now.

https://www.cs.toronto.edu/~hinton/coursera/lecture4/lec4.pd...

> No one claims linear models perform reasoning. Why are you proposing that this 3 layer (read, 3 matrix multiplies) is doing reasoning?

A 3 layer neural network is a non-linear function. It is not a linear model. There are activation functions between the layers which make it non-linear.

Re: LLMs can't do probability

#197
post #26

Earlier quoted context omitted.

If you asked a person to give you a random number between 1 and 6, would you accept if they just said a number they just came up with or would you rather they rolled a die for it?

They should turn around and ask me instead for a random number between 1 and 6 and then reply with seven minus that number.

How is that more random?

Re: LLMs can't do probability

#198

I went through all the comments here and I'm still not seeing anyone address this: If I am reading this person correctly... they prompted the model with the prompt directly 1000 times... but only for the first time. They did not allow the model to actually run a context for chat. Simply, output the first in a list of 'left' and 'right' and favor 'left' 80% of the time... but then the author only asked for the first o…

Thanks for the comment.

My point - which you actually make for me at the end of your comment - is that this stuff is probably intuitive to an NLP practitioner but not to a lay-person and therefore there's a kind of education/awareness piece which is what I'm trying to do here. There's no profound statements being made and I like to think I know my way around this stuff pretty well.

Based on the feedback I've added an update with couple of new experiments where I play with multi-turn contexts. With true RNG this shouldn't make a difference but with LLMs and the way that they use context, I figured you're probably right - it's worth trying.

Looks like (and again probably no big surprise for those of us who are familiar with these systems) multi-turn probabilistic behaviour is still not in line with what was asked for within the prompt.

Re: LLMs can't do probability

#199
post #174
post #170

Earlier quoted context omitted.

I don't think it's that hard to understand what the hell is going on with LLMs under the hood. Ultimately it's a weighted sample of the training data. It has a relationship with reality insofar as one exists within the training data. HFRL makes it easier to believe something crazy is happening because the output is being weighted towards something that's believable to us.

Depending on what you mean by "weighted sample", that's either trivially true (the network is of course a function of its training data and nothing else) or trivially false (the network generalizes over the training data and has not memorized it). It is not a good intuition pump for why an LLM can hold up one end of a conversation, or follow novel instructions - it is not reading from a script, nor regurgitating chop…

> this is true of anything that learns

Sure, but most things that learn have actual reality as a training set. LLMs have human curated data, which isn’t and can’t be perfectly representative of reality.

Re: LLMs can't do probability

#200
post #147

Earlier quoted context omitted.

That's a lot of anthropomorphizing, but I don't see anything to back up your claims.

I think it's still more in the realm of philosophy. But I do have an argument that NNs demonstrate abstract, generalized learning: the transfer learning effect. Neural networks pre-trained on data for a completely different task, learn new tasks much faster. With a GPT-like transformer, you can feed it PCM audio samples encoded as uuencoded text, or paintings encoded in the same way, and it learns how to translate En…

Abstraction seems too generous of an interpretation.

A more parsimonious hypothesis is that random networks start out broken, structurally incapable of computation because the structure has parts where information stops flowing or signal gain is so low at certain choke points that it’s presence is like a random coin flip.

Training the network to compute ANYTHING fixes this flow problem, making subsequent training easier, without introducing any kind of abstraction.

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