Descartes, Discourse on Method
And if I write in French, which is the language of my country, rather than in Latin, which is that of my teachers, it is because I hope that those who use only their pure natural reason will be better judges of my opinions than those who believe only in the books of the ancients; and, as for those who unite good sense with study, whom alone I wish to have for my judges, they will not, I feel sure, be so partial to Latin that they will refuse to hear my reasons because I express them in the vulgar tongue.
NOTE: Rene Descartes’ Discourse on Method, a philosophical work, was first published in French in 1637. The passage above is from the book’s penultimate paragraph, here in the English translation by F.E. Sutcliffe (Descartes, The Discourse on Method and The Meditations, London: Penguin, 1968).