Know-it-all agnostics

Speaking of Darwin, Marx, and Freud, G.K. Chesterton quipped:

It is yet another mark of this sort of agnostic that he is ready to assert his absolute knowledge of everything to the verge of a contradiction in terms.  Just as he will always try to write a history of prehistoric man, so he will always struggle to be conscious of his own unconsciousness . . . .

“The Game of Psychoanalysis”, Century Magazine, May 1923, quoted in Dale Ahlquist, Common Sense 101, p. 110.