He got the idea from someone else. I had the impression he doesn't attach too strongly to the idea, but he offers it as an example of how you could have a something non-deterministic happening in human cognition. That may well be understating his commitment to the idea.

It seems weak to me, but I really don't understand the details of the idea.

Too many very smart scientists have gone the same direction. Was sad to see Carl Jung go down this route.

Brilliant scientists tend to be insane weirdos. Newton was into alchemy. The kind of personality that's willing to break one orthodoxy won't stop at the next; all great new ideas are plucked from the midst of mad ramblings.