God alone, Augustine says, can act directly on souls. We cannot, but that doesn’t mean we can’t act on other souls. In Augustine’s anthropology, this is done through the body, by “signals conveyed by the physical body.” Such physical signs might be gestures, facial expressions, or “conventional indications such as words.” We act through bodies on souls when “we give orders and apply persuasion, and carry out all other actions by which souls act concerning or with other souls.” All human interaction, perhaps all human action, is semiotic.