Such ideas were founded on [Jean Jacques] Rousseau’s conviction that women were innately passive and incapable of systematic thought. […] “Woman observes,” Rousseau wrote, “man reasons.”

The search for abstract and speculative truths, for principles and axioms in science, for all that tends to wide generalization, is beyond a woman’s grasp; their studies should be thoroughly practical…. For the works of genius are beyond her reach, and she has neither the accuracy nor the attention for success in the exact sciences. As for the physical sciences, to decide the relations between living creatures and the laws of nature is the task of that sex which is more active and enterprising, which sees more things, that sex which is possessed of greater strength and is more accustomed to the exercise of that strength.

With these words Rousseau—the champion of freedom—constructed an iron cage. In a world where “great men” would increasingly use elaborate systems of scientific categorization to underwrite the verifiable “truth” of human inequality, woman was defined as inherently unfit to render such judgements. With “works of genius… beyond her reach,” she must be excluded from the erudition that would be repeatedly employed to deny her any civil or intellectual standing in the world beyond the home. She could be the named, but she could never be the namer.

Ewen & Ewen, Typecasting: On the Arts and Sciences of Human Inequality, 366-67.