Presumably the idea was that the distribution/content of the book promotes rational thinking, and that rational thinking primes you for EA. And then rather than

Presumably the idea was that the distribution/content of the book promotes rational thinking, and that rational thinking primes you for EA. And then rather than become a mathematics academic, you decide to become e.g. a quantitative trader and donate lots of money to effective causes, or take some other high-impact career decision.