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The truth conditions for the sentence "The composer Johann Sebastian Bach died in 1750" are not directly accessible to me. Can I mean that, if I say it? The tr
by gjm11 2y ago
The truth conditions for the sentence "The composer Johann Sebastian Bach died in 1750" are not directly accessible to me. Can I mean that, if I say it?
The truth conditions for "The god of the evangelical Christians exists" and "The god of the evangelical Christians does not exist" have, arguably, never been directly accessible to any ordinary human being. (Though some of their consequences could be accessible.) Can people mean such things, when they say them?
The truth conditions for "There are infinitely many prime numbers" are ... unclear, really, but maybe they're vacuous (there is no possible world in which there aren't infinitely many prime numbers) or they involve only abstracta (such as those numbers). How do you feel about the possibility of an AI saying that and meaning it, and why?
The first of these examples is the most directly relevant one. I have no direct access to the truth conditions of that sentence, but I think I can still mean it, have good reason to think it true, etc. The processes by which I got into that state involve ... learning things by reading about them, which is exactly what I think you're saying cannot in principle ever give genuine knowledge.
Anticipating a possible response: Of course many of the other things I know, some of which are relevant to the way I understand those words, I learned more directly. For instance, part of what "died" means is the cessation of various natural processes like breathing and having one's heart beat, and I have direct experience of breathing and having a beating heart. One could argue that real knowledge and understanding needs to be somehow traceable back to direct experience, and therefore LLM-type systems cannot have them. But that would be a different argument from the one you've made, and I think it's less compelling (though more likely to be right!) than the simpler "knowledge isn't real unless it's based on direct access to the relevant truth conditions".
- mjburgess 2y agoThe mechanism of access varies depending on the claim made. "the sun is engaged in nuclear fusion" could not have been meant in 100 BC. But "I have a pen in my hand" could have. Julius Caeser could have made those sounds but he could never have meant the meaning of those words. ... to mean "I have" requires an "I" to "have", and so on. So what parts of non-linguistic reality language refers to matter for evaluating whether the user means what they say. An actor is likewise pretending to mean, and a child may say something without knowing what it means (as in, eg., a claim about nuclear fusion). If two children were immitating sounds to each other, such that one "said", "the sun is nuclear fusion" and so on -- then neither in this conversation are communicating, neither know what these words mean. No child involved could ever come up with these words in this worder, and mean their meaning, they can only have this conversation via immitation. This is the case with an LLM -- it's an imitation game wherein the game is to either fool the adult overheading the child, or to generate some userful material (depending whether you're the CEO or CTO). The problem with a "predict the next word" training goal is that any patterns which emerge will only be coincidentally related to the non-linguistic reality words refer to -- because the machine isn't trained on reference: it is not participating in reality and associating words with it. The kind of participation necessary for an agent to acquire the meaning of words has no universal answer, but it always "some". An LLM has none. For a claim about a composer, an agent who means to make this claim (rather than a child who imitates the sounds of words) -- must be aware of what a composer is, and so on. They cannot mean this claim if they don't have access to the non-linguistic reality to which these words refer (or are unable, via imgiation, to simulate similar ways the world might be, such that it has composers, given their prior knowledge -- eg., they at least have to have some prior direct access to music, leading-groups-of-people, and the like). We can slightly weaken all this but it'll make no difference for an LLM -- however weak we require access, to access the meaning of words requires accessing a non-lingusitic reality. Words mean non-ligustic things -- that is their point.
- gjm11 2y agoI agree that it's possible for someone to say words that in other context would have meaning, without their having that meaning when they say it. Most of what you say merely asserts that when an LLM says something it can't truly mean it. (Incidentally, that's not quite responsive to the original claim, which is that LLMs learn meanings, not that they mean things when they say them. I think there are situations that could be described by saying that they learn the meanings of things but none the less don't mean those things when they say them. I would need to think more before trying to pass judgement on whether that's actually happening with today's LLMs, but it seems well within the range of somewhat-plausible possibilities.) The key argument you make for claiming that LLMs can't really mean things -- which I remark is not the argument you were making a couple of comments upthread -- is this bit: > The problem with a "predict the next word" training goal is that any patterns which emerge will only be coincidentally related to the non-linguistic reality words refer to -- because the machine isn't trained on reference: it is not participating in reality and associating words with it. [] The kind of participation necessary for an agent to acquire the meaning of words has no universal answer, but [...] an LLM has none. I think "coincidentally" is way too strong here. When you ask an LLM "When did J S Bach die?" and it says 1750, it isn't by coincidence that it gives a correct answer. (Considering how much they get right, despite their confabulations and whatnot, it would have to be one hell of a coincidence.) So that's a pattern in what they say that is not-coincidentally related to the non-linguistic reality. It's only indirectly related, for sure. The LLM says that Bach died in 1750 because it has read things that say that Bach died in 1750. But, again, that's also why I say that Bach died in 1750. And it seems to me that what matters, when determining whether and to what extent an utterance actually means something, is not the directness of the utterer's connection to the underlying reality, but something more like its robustness and richness. Robustness: To what extent, if the reality were different, would that tend to make the person say something different? Richness: Consider all the other bits of reality closely connected to the one in question; does our speaker's behaviour correlate with those too? If someone perpetrates an elaborate deception that makes me believe in a certain person's existence and various facts about them, when in fact everything I think I know about them is mediated by the deception, and by pure coincidence there actually is a person with those properties, unknown to my deceiver, then ... well, maybe I do "mean" what I say about them, but I don't really know what I think I know. This is a failure of robustness; changes in the underlying reality have scarcely any tendency to change my behaviour. If I learn a list of things to say about stars ("they operate by nuclear fusion", "they are mostly billions of years old", etc.) but I'm just parroting them, then robustness might not fail: maybe I learned these things by asking an astrophysicist to give me a big list of facts about stars, and if the facts were different they'd have given me a different list. But richness fails: if you ask me "would stars behave the same way if the weak nuclear force had very different parameters?" or "were there stars before there were trees on earth?" or "if we brought five more stars like the sun about as close to the sun as the earth is, what would happen to the earth and its inhabitants?", I wouldn't be able to answer unless I got lucky and one of the answers was in my list. But if both those properties do apply, then -- while of course anyone who isn't me is welcome to disagree -- I am happy to say that they "mean" what they say, or at least that what they say has meaning, and conveys actual understanding, and so on. At any rate, what they say behaves like what someone with actual understanding says: it's responsive to the facts, and it permits not only recitation of a few specific facts but something more general. Those properties of robustness and richness can be present even when learning takes place only textually. How far they're present in today's LLMs is debatable (though e.g. I think no reasonable person can deny that they are present to an extent that phrases like "stochastic parrot" would lead one not to expect) but if they aren't there it isn't just because the LLMs learn about things only via text.