[wnoise]

I'm not patching up the definition -- I'm refusing to give a definition. As a consolation prize, I'm giving examples and discussing the degree to which they fit the central concept.

My stance is that "AI or not" is not an inherent way of dividing up systems in the universe. The best attempt to answer will provide a degree, rather than a binary yes/no. Further, the degree is based on utility to humans to think about the system that way. Thus no bright line, and a multitude of context-dependent factors that weigh towards or against it. If you must force a cut-off somewhere, then that threshold is context-dependent too.