Rene Descartes wrote "A Discourse on Method" where he advocated doubt as a means to knowledge and in which he replaced rhetorical means of knowing the world with a mechanistic and analytical method using doubt to distinguish facts from mere opinions.
"My third maxim was to try always to conquer myself, . . . . . avoid precipitancy and prejudice. . . ."
(Discourse on Method, p. 41-47.)