Without defining consciousness, how can you ask where it comes from?
Here's a link to BoingBoing's take: https://boingboing.net/2019/03/18/where-does-consciousness-come.html
Another explainer video with clever graphics from Kurzegesagt is promising. It asks where consciousness comes from. Right away, the video acknowledges it has no definition of consciousness. Noting that the act of watching the video is a conscious behavior, it then breaks down core components of thought into GAIN (only focusing on hunger), DOMAIN (concept of self) and EVENT—using different terms to cover the same base perception. The video starts with the definition of "a living thing, or, self" as an axiomatic basis for consciousness. However, the integration—and in addition, the mechanism by which consciousness is known—aren't defined.
WAIT! Hive minds, collectives—none of those are living? A healthy sense of self may be vital for me and many animals like me, but not all! Sadly, the video gets off on the wrong track, even after missing the target with a title that is never answered. Yet, for all the missed opportunity, if you want to hear about primitive analogues to our sense of GAIN, DOMAIN, and EVENT in simple organisms, this video does match up with the research and results expounded here.
By breaking down the theory of mind into the most base elements, the video tries to explain that consciousness is the integrative act of those inner states of perception with the sense (I would say, inner map) of reality. But verbal consciousness, spatial consciousness, temporal consciousness, and—dare I say, emotional consciousness—may all be different ways of representing different structures of the mind, and not just one monolithic construct we lump into a single, ill-defined, term.
I'm looking forwards to more of these, to see if they continue in a more philosophical direction or ???