There is a sense in which the humanist reform of education was always Erasmus's central concern. When, a little later on, Folly refers to speech as the least deceptive mirror of the mind, the reference is to a central tenet in the humanist philosophy of education, as well as to one of Erasmus's own Apothegmata. Eloquence, or style, not only mirrors intellectual qualities, but can become the means of inculcating and developing them. From this central tenet, clearly implied by Erasmus in an important series of letters to Colet, derives the importance of the Renaissance debate about the relationship between eloquence and philosophy (or between dialectic and rhetoric).