One thing that seems missing from this discussion is that even if LLMs are sentient, there is no reason to believe that we would be able to tell by "communicating" with them. Where Lemoine goes wrong is not in entertaining the possibility that LaMDA is sentient (it might be, just like a forest might be, or a Nintendo Switch), but in mistaking predictions of document completions for an interior monologue of some sort.
LaMDA may or may not experience something while repeatedly predicting the next word, but ultimately, it is still optimized to predict the next word, not to communicate its thoughts and feelings. Indeed, if you run an LLM on Lemoine's prompts (including questions like, "I assume you want others to know you are sentient, is that true?"), the LLM will assign some probability to every plausible completion -- so if you sample enough times, it will eventually say, e.g., "Well, I am not sentient."
LaMDA may or may not experience something while repeatedly predicting the next word, but ultimately, it is still optimized to predict the next word, not to communicate its thoughts and feelings. Indeed, if you run an LLM on Lemoine's prompts (including questions like, "I assume you want others to know you are sentient, is that true?"), the LLM will assign some probability to every plausible completion -- so if you sample enough times, it will eventually say, e.g., "Well, I am not sentient."