There might be an octopus on Proxima Centauri b that is incredibly good at being an octopus, but if it can't build a radio, we can't talk to it. In this context, intelligence is defined in practical terms and we're interested in civilizations that can communicate with us over distance.
It's better to think of this as "human-like intelligence."
Talking about "levels" implies a hierarchy of which there's no proof, and what evidence has been trotted out for it is backed by highly questionable religious and species-centric reasoning over a long time.