[2.6.8] St Augustine’s Just War Theory

St Agustine (354-430 AD) in the City of God (De Civitate Dei) and other works proposes a theory of how to initiate and conduct a just war. He thinks that:

  • Because of the pride, vanity, and fallen nature of man, wars between political states (see [2.6.7]), sects, religions are present in the world.
  • Wars have a coercive role in God’s plan for humanity.
  • Killing in wars is permissible even for Christian soldiers – as agents of the law, if the killing avoids a greater evil.
  • Christians involved in wars should decide and conduct wars in a just way.

In the UML Activity Diagram below, I propose a representation of the “business” process of decision-making and conducting a just war. The actions marked with yellow and cyan are St Augustine’s criteria.

Augustine’s just war theory
DECISION ABOUT JUST WAR Check if there is a just cause for war: “such as to defend the state from external invasion; to defend the safety or honor of the state, with the realization that their simultaneous defense might be impossible; to avenge injuries; to punish a nation for failure to take corrective action for wrongs (legal or moral) committed by its citizens; to come to the defense of allies; to gain the return of something that was wrongfully taken; or to obey a divine command to go to war (which, in practice, issues from the political head of state acting as God’s lieutenant on earth); and in any case, the just cause must be at least more just than the cause of one’s enemies”.

Check if there is a rightly intended will for war: “which has the restoration of peace as its prime objective, takes no delight in the wickedness of potential adversaries, views waging war as a stern necessity, tolerates no action calculated to provoke a war, and does not seek to conquer others merely for conquest’s sake or for territorial expansion”.

Check if the war is declared by a competnet authority

Check if the war is the last resort in order to achieve the objective of the just cause.
Declare war Declare war by a competent authority
CONDUCT JUST WAR Plan military action

Check if the military action is proportional to “the wrong to be avenged, with violence being constrained within the limits of military necessity”

Check if the military action discriminates between objects of violence (that is, combatants) and noncombatants, such as women, children, the elderly, the clergy”

Check if the military action observes good faith in its interactions with the enemy, by scrupulously observing treaties and not prosecuting the war in a treacherous manner.”

Conduct military action

Check if war’s objective is reached


First published: 30/1/2020

[2.6.6] St Augustine on Will and Predestination

St Agustine (354-430 AD) writes extensively about the importance of the will and free will a series of books (De civitate deiDe ordineDe beata vitaConfessionesDe trinitate), here are some highlights of his thoughts (see also [2.5.1]):

  • Love directs will towards an object (God, neighbor, self, etc.).
  • Will appears if assent (in the stoic sense) is given to the impulse (see [2.2.1])
  • First-order volitions within the human soul aimed to concrete objects can conflict, second-order volitions can solve this conflict.
  • Divine grace is necessary for restoring the freedom of the will for the fallen humankind.
  • God provides grace to the elected ones, who will be able to achieve salvation, and avoid damnation (theory of double predestination).

The OntoUML diagram below presents the main components of Augustine’s theory of the Will:

St Augustine on will
Love“In a more general way, love means the overall direction of our will (positively) toward [an object:] God or (negatively) toward ourselves or corporeal creature (De civitate dei 14.7; […]).” directs Will; in relation with Object
Will“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. ..
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).”
FirstOrderVolition“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.”is subkind of Will; mediates between Love and Object
SecondOrderVolitionSecond-order volition “acts of the liberum voluntatis arbitrium, the ability to choose between conflicting first-order volitions”. is subkind of Will; chooses between conflicting FirstOrderVolitions
AssentToImpulse“The mechanics of the will in Augustine’s moral psychology is strongly indebted to the Stoic theory of assent [to impulse], 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 [to impulse], 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)”characterizes Will
GodChristian God provide grace to the choosen ones (predestination).provides Grace
Grace“Divine grace is necessarry for restoring the freedom of the will for the fallen human: “By c. 400 CE, Augustine had come to the conclusion that our ability to make choices was seriously impaired by the fallen condition of humankind and that it made little sense to talk about free will without reference to grace. The optimistic-sounding claim in the first book of De libero arbitrio (1.25–26; 29) that it is in our power to be good as soon as we choose to be good because ‘nothing is as completely in our will as will itself’ was probably never the whole story; already in book 3 of the same work Augustine says that the cognitive and motivational deficiencies caused by Adam’s sin […] seriously compromise our natural ability to choose the good […], he radicalizes this to the idea that original sin makes us unable to completely subdue our sinful volitions as long as we live, so that we live in a permanent state of “akrasia” or weakness of will (De natura et gratia 61–67; De civitate dei 19.4; De nuptiis et concupiscentia 1.35). But he never questions the principle that we have been created with the natural ability to freely and voluntarily choose the good, nor does he ever deny the applicability of the cogito argument to the will (cf. De civitate dei 5.10) or doubt that our volitions are imputable to us. What grace does is to restore our natural freedom; it does not compel us to act against our will.”is necessary for freedom of the Will
ObjectThe Object of Love


  • All citations from: Mendelson, Michael, “Saint Augustine“, The Stanford Encyclopedia of Philosophy (Winter 2018 Edition), Edward N. Zalta (ed.)

First published: 16/01/2020
Updated: Added God and predestination 01/05/2020