All teaching and all intellectual learning come about from already existing knowledge. - Aristotle, Posterior Analytics (71a 1), tr. by Jonathan Barnes (1984/95) Other translations of this quote: All doctrine, and all intellectual discipline, arise from pre-existent knowledge, O.F. Owen (1853) All communications of knowledge from teacher to pupil by way of reasoning pre-suppose some pre-existing knowledge., E.S. Bouchier (1901) All instruction given or received by way of argument proceeds from pre-existent knowledge, G.R.G. Mure (1928) http://en.wikiquote.org/wiki/Knowledge