Maybe modulating temperature can help here: have the LLM come up with ideas at high temperature, and then critique them at low.

This is also tied to halucinations: it is something that humans do (for writing fiction, and for "jumps") - but what LLMs currently lack is intellectual honesty. Coming up with bullshit is fine (and in this context valuable) - the important bit is putting those ideas through some form of rigor, or just immediately turn around and admit to talking shit.

So I'd arge that hallucinations are what prevent LLMs from doing this in a useful way.