Aristotle, Cicero, Augustine, and Thomas Aquinas' Theories of Just War

            I have been reading a book by Craig M. White called IRAQ The Moral Reckoning. The book applies the ancient just war theory to the 2003 decision to go to war with Iraq. Although the book has a large focus on modern applications of the just war theory it also gives a very good overview of the different just war theories that originated in antiquity.

            There are two main branches of the just war theory: jus ad bellum and jus in bello. The former is concerned with the justice in going to war and the latter the justice in the conduct of war. White’s book only focuses on the justice in going to war as I will in this post.

            According to White, just war theory does have its roots in ancient Greece and Rome, however he believes that it has changed a great deal in the modern world. The first reason for this is that ancients had a very different set of beliefs about what was right and wrong. The second reason is that even when ancient writers addressed a series of moral issues they never unified these issues into a single coherent whole.

            Aristotle’s ideas of morality are much different than ours today for example. Aristotle says that some just causes for war for people of his time are: repelling or avenging aggression; fighting on behalf of kinsman or allies; the need to increase the glory, strength or resources of our home state. In Aristotle’s politics he says that wars “of acquisition” are like hunting, and says that wars that subjugate men who “ought to be governed” by others is “naturally just”. This idea from Aristotle relates to the ancient’s belief in slavery as moral and just. Today it would be very rare for a political leader to say that we ought to go to war to subjugate others that ought to be governed.

“Neither should men study war with the view to the enslavement of those who do not deserve to be enslaved”

            Aristotle believes that the dominion over one’s neighbors is a perfectly acceptable justification of war if it is done in moderation. Aristotle still rejects that war is good in of itself and says that peace is what we should strive for in general. Like Cicero’s idea of a just war from my last post, Aristotle also believes that “We make war in order that we may live at peace”. Cicero takes it a step further by concluding that when there is a dispute the first course of action should be discussion and then one should only result to physical force if discussion does not resolve the problem. Aristotle and Cicero both agree that war is not honorable itself and one should always strive to avoid it.

            At the end of one of Cicero’s books in the Commonwealth he says that “honor” and “safety” are the only two reasons that one can make a just war. In Cicero’s Commonwealth Book III he outlines exactly the criteria for a just war: a proper motive, a due announcement and proclamation, and a prior demand of restitution.

            Augustine who lived through the sack of Rome in 410 AD was the first Christian writer to address the subject of when a war may be just. Previously the teachings of Jesus suggest that self-defense was not permissible, hence the phrase “turn the other cheek”. Augustine bases much of his theory on Aristotle and Cicero. Augustine argues that the proper role of the government is to maintain peace, and this requires the ability to wage war when necessary. He says that “lawful authority” must authorize going to war. On the other hand, Jesus states in the gospel, “All they that take the sword shall perish with the sword”. This suggests that early Christian teachings taught pacifism instead of just war. Augustine takes that quote to mean that to mean that one cannot take up arms against another unless authority was given to do so. I found it very interesting that he made this assumption based on the passage from the Bible.

            Thomas Aquinas was a medieval philosopher and theologian who essentially gathered and synthesized Augustine’s theories. Aquinas’ title from the section in Summa Theologica was “Whether it is always sinful to wage war?” In this he denies that it is “altogether” sinful to wage war. Aquinas then lays out three conditions for waging war: sovereign authority, just cause, and right intention. He then goes further than Cicero by offering a wide range in the meanings of these terms.

Aristotle

Cicero

Augustine

St. Thomas Aquinas