Desire for knowledge is the mark of the beast: Aristotle says "All men reach out to know" (Metaph.A. 1.980a21). As you perceive the edge of yourself at the moment of desire, as you perceive the edges of words from moment to moment in reading (or writing), you are stirred to reach beyond perceptible edges—toward something else, something not yet grasped. The unplucked apple, the beloved just out of touch, the meaning not quite attained, are desirable objects of knowledge. It is the enterprise of eros to keep them so. The unknown must remain unknown or the novel ends. As all paradoxes are, in some way, paradoxes about paradox, so all eros is, to some degree, desire for desire.
Anne Carson