Just as the light of the sun irradiates the organ of vision and things visible, enabling the former to see and the latter to be seen, so too the irradiation of a spiritual light brings the mind into relation with that which is intelligible.

Commentary on Aristotle's Posterior Analytics, i.17 as quoted by Francis Seymour Stevenson, Robert Grosseteste: Bishop of Lincoln, p. 52 (footnote 2)