Last common ancestor was 600m years ago [0], “nearly twice as long as the step … to find the common ancestor of birds and mammals.”

0. https://www.amazon.com/Other-Minds-Octopus-Origins-Conscious...

My recollection of octopus eye development comes from "Other Minds" by Peter Godfrey-Smith, which you might like. Essentially the octopus brain like organs are another evolutionary convergence.

https://www.amazon.com/Other-Minds-Octopus-Origins-Conscious...

This week's EconTalk covers a theory of self consciousness coming about only after humans had words to describe it. I wonder if likewise the brain as a physical substrate for a mind can only come about from a set of sense organs like eyes.

Jaynes' idea was that if you went back and you looked at very early historical texts--particularly for him, the Iliad--the way that characters talk about their own minds and their own drives is extremely unusual, or you might say not at all modern. . . . But, what's actually going on, given what we know about the specialization between the hemispheres of the brain, is that essentially one side of the brain, one hemisphere of the brain is really communicating to the other. And, full human consciousness had not really been established at that time.

https://www.econtalk.org/erik-hoel-on-consciousness-free-wil...

I highly recommend the book "Other Minds", a fascinating and very accessible book about the octupus and cuttlefish. They are amazing creatures.

https://www.amazon.com/Other-Minds-Octopus-Origins-Conscious...

I read the book "Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness" last year. Very interesting book about octopi. https://www.amazon.com/Other-Minds-Octopus-Origins-Conscious...

Nice rip off of https://www.amazon.com/Other-Minds-Octopus-Origins-Conscious...