This philosophy thesis is in the area of Metaphysics. It offers an account of the role of Imagination in human understanding. This account elaborates and clarifies Aristotle's theory of the "four causes". In that connection the author particularly favors J.M. Moravcsik's article "Aitia as generative factor in Aristotle's philosophy," appearing in the journal Dialogue (1975), 14: pp 622-638. A variety of other philosophers are cited, including Hume and Kant; and Ortega and Hegel (regarding the dialectical development of philosophy). Several artists and literary figures, such as William Blake and Marlowe's Dr. Faustus, are also quoted. A curious argument in the thesis asserts that there is nothing "in reality or in the dream" which is beyond the purview of the Imagination; hence the reach of the Imagination is co-extensive with the Absolute (reality as we can possibly conceive it). The argument goes like this "by definition, one cannot imagine the unimaginable, thus, no counterexamples can be found to counter the claim that the Imagination circumscribes the Absolute".