The good teacher is a man or woman of exceptionally wide and lively intellectual interests. It is useless to think of teaching as a business, like banking or insurance: to learn the necessary quota of rules and facts, to apply them day by day as the bank-manager applies his, to go home in the evening and sink into a routine of local gossip and middle-brow relaxation (radio, TV, the newspaper, and the detective-story), to pride oneself on being an average citizen, indistinguishable from the dentist and the superintendent of the gas-works — and then to hope to stimulate young and active minds. Teachers in schools and colleges must see more, think more, and understand more than the average man and woman of the society in which they live. This does not only mean that have a better command of language and know special subjects, such as Spanish literature and marine biology, which are closed to others. It means they must know more about the world, have wider interests, keep a more active enthusiasm for the problems of the mind and the inexhaustible pleasures of art, have a keener taste even for some of the superficial enjoyments of life — yes, and spend the whole of their career widening the horizons of their spirit. Most people, as we see, stop growing between thirty and forty. They “settle down” — a phrase which implies stagnation — or at the utmost they “coast along,” using their acquired momentum, applying no more energy, and gradually slowing down to a stop. No teacher should dream of doing this. His job is understanding a large and important area of the world’s activity and achievement and making it viable for the young. He should expect to understand more and more of its as his years go by.
Gilbert Highet, The Art of Teaching, pp. 48-49