Interpretation in Piers Plowman treats the poem as the work of a fourteenth-century intellectual--that is, as the work of a litteratus, one obsessed with written texts, who interprets all human experience on the model of textual interpretation. But instead of providing a theory of interpretation, Langland shows what happens when incommensurable interpretive systems collide. The dreamer in the poem learns that the intellectual's lust for self-justification on the model of textual argument is futile and self-destructive, and yet that the intellectual must approach God, if at all, through texts. Literacy turns out for the intellectual to be itself instrumental like sin: an understanding of the wrongness of wanting to master texts in order to justify oneself provides the stimulus for a necessary refocusing of one's life.