Aristotle's concept of nous (intellectual intuition) — the faculty that grasps first principles directly, without discursive reasoning — is the philosophical ancestor of the poet's insight, the sudden perception of a truth that cannot be arrived at by argument; The Romantic concept of imagination (Coleridge's primary and secondary imagination, Keats's "negative capability") is a form of insight — the capacity to perceive the whole in the particular, to grasp intuitively what analysis cannot reach; A poet writing about a moment of sudden understanding — whether mathematical, ethical, or spiritual — might philosophically distinguish insight from discursive reasoning, using the poem to enact rather than merely describe the instantaneous quality of genuine insight; Husserl's phenomenological concept of eidetic intuition — the direct perception of essential structures — provides a philosophical account of how poetic insight might work, grasping the essential form of experience beneath its contingent surface; Heidegger's concept of Lichtung (clearing) — the opening in which beings show themselves — is a spatial-philosophical figure for the moment of insight, when what has been concealed is suddenly illuminated; William Blake's concept of "seeing through the eye, not with it" is a philosophical claim about poetic insight as a different mode of perception from ordinary sensory observation — a visionary capacity to perceive what sense alone cannot reach