Theories cannot claim to be indestructible. They are only the plough which the ploughman uses to draw his furrow and which he has every right to discard for another one, of improved design, after the harvest.
Nobel Lectures, Chemistry 1901-1921 - Nobel lecture for award received in 1912, The Method of Direct Hydrogenation by Catalysis (pp. 230-231) - Elsevier Publishing Company. Amsterdam, Netherlands. 1966