This study began with the consideration of aspects of love, knowledge, and sight in the metaphysical tradition that informs late medieval thought, and showed how those three terms form a complex system of parasitisme. It is in the metaphysical tradition that the relationship and tensions between love and knowledge are most evident and the development of which are easiest to trace; the motif of sight gives metaphysical writers perhaps their greatest access to these terms. Metaphysics informs later medieval natural philosophy and epistemology. The discourse of light and sight in these other disciplines ensures the viability of an extended consideration of the relationship between love and knowledge. This parasitisme is extensive and enters love literature at several points. It does so where literary convention accentuates the role of the eyes and draws upon natural philosophy and psychology to emphasize the nature and extent of their power; it does so also where love and knowledge represent a conventional bipolar opposition. The system of parasitisme, however, both confirms and confounds the anticipated hostility between love and knowledge. This situation is recognized, explored, and exploited by Chaucer and other medieval love poets with wide-ranging intellectual interests, among which are questions of the poet's position and what is involved in artistic expression. The functioning of love, knowledge, and sight stimulates Chaucer's discursive intellect; it proffers him both an opportunity and a model to explore his role as poet.