That's part of his arguments, that some corners of quantum physics that still elude us (quantum gravity and all that) may be undecidable. He then goes on to exp

That's part of his arguments, that some corners of quantum physics that still elude us (quantum gravity and all that) may be undecidable. He then goes on to explain how he thinks these phenomena could have an influence on cognition. I don't really buy this theory, but the book is basically 80% "here's what we know" and 20% "here's what I conjecture" so it's still a worthwhile read IMO. It's worth noting that it's a book from the late 80's however, so it's a bit outdated in some parts (he didn't know that the universe's expansion was accelerating in particular, which renders his discussion of the curvature of the universe a bit obsolete).