He wrote astronomers and particle physicists as well don't produce much more useful results, but are excellent at selling their work as important, while humanists lack any good PR for their subject.
Except for the economists - arguably not so human at all, but easily the most successful of the humanities.
PR is usually seen as 'public education' - it's not usually acknowledged that it has a direct influence on research funding and future research directions.
More specifically, they claim they understand their subject well enough, at a quantitive level, to do detailed prediction and policy prescription, something the humanities in general are very reluctant about.