It isn't slippery to grasp--it just seems so straightforwardly wrong that one thinks you must have meant something else.

"The map is not the territory" comes to mind as a six-word refutation.

"Liquidity" describes a state where the temporal evolution of a substance has certain regularities, but those regularities are there whether or not we have noticed them and put labels on them. When talking about the emergence of liquidity, we are talking about the regularities themselves, not our mental representation of them. The emergence of liquidity is a matter of ontology. Knowing what is liquid, and what liquidity is, is a matter of epistemology.

Furthermore, the existence of a circular argument doesn't make the conclusion wrong, it just leaves one in doubt whether the whole edifice is correct or incorrect. So it is ultimately unsatisfying, but in some cases one may be able to do no better (c.f. coherentism). "Once upon a time logical fallacy, therefore strong emergence, the end!" is not a very compelling argument.

I don't see anything slippery except that maybe you slipped up in conceptualizing the task.