I found a lot of interesting, if speculative, thoughts in the article, but...

> Superhuman means unverifiable

is not true for at least large classes of problems. The recent solution of the "unit distance" problem comes to mind, or any future AI-solved math problem that was beyond the capabilities of humans. You can tell it's superhuman (it's doing things humans can't) and you can easily verify its results are correct.

For other classes of problems (eg, policy suggestions for large scale systems like the economy), the point is fair.