The vaccination theory of education

English is not History and History is not Science and Science is not Art and Art is not Music, and Art and Music are minor subjects and English, History and Science major subjects, and a subject is something you "take" and, when you have taken it, you have "had" it, and if you have "had" it, you are immune and need not take it again.

Postman, N. & Weingartner, C., Teaching as a subversive activity, New York, Delacorte Press, 1969, p.21.