Culture means … the cultivation of the mind, the taking care and improving of the native faculties of the mind in accordance with the nature of the mind. Just as the soil needs cultivators of the soil, the mind needs teachers. But teachers are not as easy to come by as farmers. The teachers themselves are pupils and must be pupils. But there cannot be an infinite regress: ultimately there must be teachers who are not in turn pupils. Those teachers who are not in turn pupils are the great minds.

What is liberal education, p. 3 - Liberalism Ancient and Modern (1968)