The meanings we assign to words like “understanding”, “sentience”, “consciousness” imply really a very high degree of shared context and cultural baggage. If we expand those terms to include systems radically unlike us, then they could be literally anything and everything, from weather systems to laws of physics—but we don’t think of those words in this way; if we can’t reason about sentience or understanding from our vantage point, then for all intents and purposes there is no sentience or understanding. This catch-22 brings together the fallacies of believing in aliens and believing in AGI: we yearn for sentient non-humans, but we only recognize human-like sentience.
One human mind is a lot like another human mind, markedly less like one of an octopus or a dog (still enough similarity that the concept of, e.g., “hurt” kind of makes sense), but really unlike an LLM (and I’m not going to get into an argument as to why an LLM is fundamentally different from a human mind and why we are not even close and possibly can never be to achieving that, the only way of producing new systems like us remaining childbirth; if you don’t agree on that part then it’d be useless to discuss the matter further). We have an uncanny situation where a system radically unlike us can produce output that is mostly similar to what another human mind might produce, but unless we accept that everything around can be conscious (and believe in gods and spirits again) it’s not even a question as to whether the system can understand any of the symbols it produces or have consciousness in the commonly accepted meaning of those terms: it’s only a tool.
Note that I’m not against widening our concept of sentience, just saying it needs to happen if we want to grant an LLM sentience; and if this widening does happen, a sentient language model would be small beans compared to a philosophical revolution we’d have on our hands then.