I think by "critical thinking" he means the ability to criticize, or point out flaws in someone's work/theory. And I took a good number of classes in the human

I think by "critical thinking" he means the ability to criticize, or point out flaws in someone's work/theory. And I took a good number of classes in the humanities where this is basically what we were expected to do: "Critically analyze Spinoza's theory of X" usually meant "Discuss what you think is stupid about Spinoza's theory of X." You could do otherwise, but you weren't expected to. Apparently coming up with your own theory, and "critically analyzing" THAT, is something special reserved for a senior thesis. But while all science majors did research projects or programming projects, only the really motivated humanities students did a thesis. Many spent four years just smugly putting down the half-formed ideas of long-dead scholars, and probably poorly.