> By total coincidence, some hallucinations happen to reflect the truth, but only because the training data happened to generally be truthful sentences.
It's not a "total coincidence". It's the default. Thus, the model's responses aren't "divorced from any concept of truth or reality" - the whole distribution from which those responses are pulled is strongly aligned with reality.
(Which is why people started using the term "hallucinations" to describe the failure mode, instead of "fishing a coherent and true sentence out of line noise" to describe the success mode - because success mode dominates.)
Humans didn't invent language for no reason. They don't communicate to entertain themselves with meaningless noises. Most of communication - whether spoken or written - is deeply connected to reality. Language itself is deeply connected to reality. Even the most blatant lies, even all of fiction writing, they're all incorrect or fabricated only at the surface level - the whole thing, accounting for the utterance, what it is about, the meanings, the words, the grammar - is strongly correlated with truth and reality.
So there's absolutely no coincidence that LLMs get things right more often than not. Truth is thoroughly baked into the training data, simply because it's a data set of real human communication, instead of randomly generated sentences.