  Above and beyond these “created” causes, knowledge also requires an “eternal” cause. In the mental acts of abstracting universals and arguing inductively, the human mind generalizes well beyond the data of our experience. It is one thing to be able to generalize so, quite another to be sure one has succeeded. Intuition into the essence of a creature involves truths that are not only universal, but also necessary and certain. God is acquainted with the full extension of any universal, since the divine idea of any truth consists in knowledge of that truth in absolutely all its actual and possible instantiations. The infinite extension of God’s knowledge is what makes divine understanding certain, and this certainty in the divine mind is on loan, so to speak, to the human mind. “If full knowledge requires recourse to a truth which is fully immutable and stable, and to a light which is completely infallible, it is necessary for this sort of knowledge to have recourse to the heavenly art as to light and truth: a light, I say, which gives infallibility to the [created] knower, and a truth which gives immutability to the [created] object of  knowledge.”[48]  Here Bonaventure makes more precise Augustine’s “light” and “truth.” They are the two sides of certitude, so it is the certainty, and only the certainty, found in human knowledge that requires divine illumination; all other features of human knowledge–abstraction, universality, correspondence–come from created causes.