He usually explains the details right after stating it. For example, you can follow along in his lecture notes: https://www.scottaaronson.com/democritus/lec9.ht

He usually explains the details right after stating it. For example, you can follow along in his lecture notes: https://www.scottaaronson.com/democritus/lec9.html https://www.scottaaronson.com/democritus/lec9.html . "Statistics but with the 2 norm" is really just a succinct way of stating the postulates of quantum mechanics, and obviously all effects of quantum mechanics are determined by the postulates. So you shouldn't really see this as a statement that's controversial at all.