how the soul experiences itself active

Reply to Objection 4. Someone might answer by referring to Augustine's statement (De Trin. xiv, 6), that "the mind ever remembers itself, ever understands itself, ever loves itself"; which some take to mean that the soul ever actually understands, and loves itself. But he excludes this interpretation by adding that "it does not always think of itself as actually distinct from other things." Thus it is clear that the soul always understands and loves itself, not actually but habitually; though we might say that by perceiving its own act, it understands itself whenever it understands anything. But since it is not always actually understanding, as in the case of sleep, we must say that these acts, although not always actually existing, yet ever exist in their principles, the habits and powers. Wherefore, Augustine says (De Trin. xiv, 4): "If the rational soul is made to the image of God in the sense that it can make use of reason and intellect to understand and consider God, then the image of God was in the soul from the beginning of its existence."
(Whole context in philosophy notes)