The Horatian formula holding that a poem should instruct and delight raises two obvious questions: what is ‘instruction’ and what is ‘delight’? These are difficult questions, since they seem too broad to be answerable and too central to be dismissed. They are difficult, also, because they refer to paired terms. Are we to see instruction and delight related in some kind of sequence? And what of the cases where only one term appears and the other not at all?

These are the basic questions generated by a consideration of the Horatian formula as it occurs in medieval and Renaissance critical texts and it is the purpose of this paper to show that the formula in these texts can be coherently interpreted through the use of the then dominant faculty psychology.

In his far-ranging study, Rabelais and His World, Mikhail Bakhtin describes Erasmus’ Praise of Folly as the most complete expression in the Renaissance of Medieval Latin humour and as ‘one of the greatest creations of carnival laughter in world literature.’ For all Erasmus's wit and comic irony, the Praise of Folly might seem an unlikely embodiment of the comic spirit central to Carnival and other popular festivals such as New Year's, May Day, Midsummer, and the Twelve Days of Christmas. In the light of Bakhtin's remarks, however, I will here explore the importance of popular traditions of Carnival and other holiday celebrations for understanding the spirit and structure of Erasmus’ work.