 Though other Latin philosophers, especially Seneca, had made use of the concept of will (voluntas) before Augustine, it has a much wider application in his ethics and moral psychology than in any predecessor and covers a broader range of phenomena than either Aristotelian boulesis (roughly, rational choice) or Stoic prohairesis (roughly, the fundamental decision to lead a good life). Augustine comes closer than any earlier philosopher to positing will as a faculty of choice that is reducible neither to reason nor to non-rational desire. It has therefore been claimed that Augustine “discovered” the will (Dihle 1982: ch. 6; Kahn 1988; contrast Frede 2011: 153–174 who, mainly on the basis of De libero arbitrio, emphasizes Augustine’s indebtedness to Stoicism). Augustine admits both first-order and second-order volitions, the latter being acts of the liberum voluntatis arbitrium, the ability to choose between conflicting first-order volitions (Stump 2001; Horn 1996; den Bok 1994). Like desires, first-order volitions are intentional or object-directed and operate on all levels of the soul. Like memory and thought, will is a constitutive element of the mind (see  6.2 The Human Mind as an Image of God).  It is closely related to love and, accordingly, the locus of moral evaluation. We act well or badly if and only if our actions spring from a good or evil will, which is equivalent to saying that they are motivated by right (i.e., God-directed) or perverse (i.e., self-directed) love (De civitate dei 14.7).  With this basic idea in view, Augustine defends the passions or emotions against their Stoic condemnation as malfunctions of rational judgment by redefining them more neutrally as volitions (voluntates) that may be good or bad depending on their intentional objects (De civitate dei 9.4–5; 14.9; Wetzel 1992: 98–111; Byers 2012b). The mechanics of the will in Augustine’s moral psychology is strongly indebted to the Stoic theory of assent, which it however modifies in at least one respect. As in Stoicism, the will to act is triggered by an impression generated by an external object (visum). To this the mind responds with an appetitive motion that urges us to pursue or to avoid the object (e.g., delight or fear). But only when we give our inner consent to this impulse or withhold it, does a will emerge that, circumstances permitting, results in a corresponding action. The will is the proper locus of our moral responsibility because it is neither in our power whether an object presents itself to our senses or intellect nor whether we take delight in it (De libero arbitrio 3.74; Ad Simplicianum 1.2.21), and our attempts to act externally may succeed or fail for reasons beyond our control. The only element that is in our power is our will or inner consent, for which we are therefore fully responsible. Thus, a person who has consented to adultery is guilty even if his attempt actually to commit it is unsuccessful, and a victim of rape who does not consent to the deed keeps her will free of sin even if she feels physical pleasure (De civitate dei 1.16–28). Augustine therefore defines sin as “the will to keep or pursue something unjustly” (De duabus animabus 15). The second stage in the above structure, the involuntary appetitive motion of the soul, is reminiscent of the Stoic “first motions”, but it also corresponds to the “impulse”, which in Stoicism does not precede consent but follows it and immediately results in action. Temptations of this kind are, in Augustine, not personal sins but due to original sin, and they haunt even the saints. Our will must be freed by divine grace to resist them (Contra Iulianum 6.70; see, on this theory and its Stoic and Platonic background, Byers 2013: 100–150; J. Müller 2009: 157–161; Sorabji 2000: 372–384; Rist 1994: 176–177).