As is well-known, Hegel follows Aristotle in identifying thinking as the characteristic activity of both the human and the divine being. The relation between rational animality and divinity, however, has always been ill-understood. Readers of Aristotle have puzzled over his account of the active intellect in De Anima 3.5 for millennia, just as interpreters of Hegel, since his death in 1831, have struggled to give a satisfactory account of his central concept of spirit, reaching widely diverse and often contradictory conclusions. The main difficulty is in reconciling these thinkers' hylomorphism and naturalism with their seemingly theological characterizations of mind—with the mind's separateness or absoluteness, immortality or eternality. The usual solution to this difficulty is either (1) to drop one set of terms (or at least to emphasize one at the expense of the other), so that mind is conceived as either simply natural or simply divine, or (2) to keep both terms in some sort of dualistic relation (e.g., God's mind is infinite and immortal while ours is finite and mortal). To understand Aristotle and Hegel, however, we must understand the mind's immortality or eternality without abandoning the hylomorphic and naturalistic conception of the mind as a function of the living body. To that end, this dissertation undertakes a fresh examination of Aristotle's and Hegel's accounts of soul and mind, attempting a reconciliation by paying particularly close attention to their metaphors or physical associations, i.e., Aristotle's "natural light" and Hegel's "spiritual time."