"It is not the physical world in general. As far as we can tell it occurs in most brains."

Part of the embodied cognition idea is that a brain is not necessary. Even bacteria maintain an inside and an outside, move towards or away from things outside, and behave. Descarte and others would call this machine-like, drawing a hard line between life and non-life, but what if consciousness is a graded variable and not a binary one?

Three books on this idea:
Kriti Sharma, Interdependence: Biology and Beyond (dense but short)
Evan Thompson, Mind and Life (dense and long)
Douglas Hofstadter, I Am a Strange Loop (popular science)