The corresponding section in the beginning of Scott Aaronson’s “Quantum computing since Democritus” (the online version works[1]; see also the related blog post[2]). It’s short and to the point (unlike GEB) and enough to understand why something in this vein must be true. It’s not detailed enough, though, to understand each of the technical conditions in the standard statement individually (no explanation of ω-consistency and the like).
[1] https://www.scottaaronson.com/democritus/lec3.html
[2] https://scottaaronson.blog/?p=710