You and me think we are but we can't be sure, and many before us have raised a doubt.
As for the prompt(s), to use such a limiting term, they could as well come from a self-reinforcing loop that starts when we're born and is influenced by external stimuli.
LLMs as part of a bigger system that keeps prompting itself, perhaps like our internal conscious thought processes, sounds a lot more like something that might be headed towards AGI. But LLMs on their own aren't it.
As for the prompt(s), to use such a limiting term, they could as well come from a self-reinforcing loop that starts when we're born and is influenced by external stimuli.