September 2014 Print

War and Peace


by Fr. Jean-Baptist Guyon

The history of mankind is an endless alternation of peace and war. But ultimately, what is war? And what is the essence of peace? What are the conditions for just war or lasting peace? Without clear answers to these questions no one can seriously begin to reflect upon such serious topics.

Common sense rightly opposes the two terms war and peace. War is the contrary of peace, and vice versa. Now, quite logically,1 in order to come to an understanding of one thing it often helps to study its opposite, which amounts to saying that a deeper understanding of the notion of war can be of great help to understanding better what peace is. And so, in the first part we shall define the notion of war so as to bring into relief the idea of peace in all its plenitude. Then we shall show that war, though not always evil in and of itself and sometimes a legitimate means, always ushers in countless evils, such that peace, the remedy to these evils, must be sought, the theme of the third part.


Before defining war, it behooves us to turn toward the cradle of wisdom, the ancient Greek world, for, as Jacques Maritain observed, Greece is the only place in Antiquity where the wisdom of man found its way and human reason attained force and maturity.2 In ancient Greek thought, the term for war, polemos, whence derives the word polemic, occupies a fundamental place. Heraclitus of Ephesus, a philosopher from the end of the sixth century B.C., did not hesitate to coin this still-quoted aphorism: “War is the father and king of all.”3 Beyond the notion of armed conflict, which is but one, albeit the most visible, expression of war, the Greeks conceived the notion of polemos more broadly, seeing in it the logic of strife and conflict that exists in all things, particularly in the affairs of men and in human relations.

Far from limiting polemos to bellicosity, the Greek world observed in all simplicity and disingenuous wisdom that “getting along”—be it in a family or in a city—is the result of an apprenticeship in which people strive to live with others through the contrarieties, strife, and conflicts that come along and that must be gradually overcome. Isn’t it commonly observed that an adolescent “forges” his personality through the opposition he meets with at home and at school.

Here, then, is the first sense, quite broad, of the polemos of the Greeks which we translate by war. This way of seeing things already suggests a reflection: If war in the broad sense, such as Heraclitus describes it, is, in the actual state of human nature, an unavoidable given, then the establishment of universal peace here below takes on an illusory character, even if more peace is desirable. Hence, the Greek concept of polemos in and of itself eliminates the two extremes constituted by exaggerated bellicosity on the one hand and complacent pacifism on the other.

A Pesto, Fame, et Bello...

Leaving the Greek world, the cradle of ancient wisdom, we turn to the Christian West in order to advance our quest to define war. In the Catholic conception, war is considered as one of the great scourges of humanity: “A peste, fame, et bello, libera nos, Domine—from plague, famine, and war, deliver us, O Lord.” This supplication addressed to God in the Litany of Saints is very meaningful: war is associated with the worst disorders that can afflict our poor human race. Quite early, Vincent of Beauvais, in his Speculum Doctrinale, taught that the name for war, bellum in Latin, is derived from bellua, wild beast, because, he writes, “quite often those who wage war imitate the cruelty of wild beasts.”4

Abstracting from its grim reality, in the West war is considered from the aspect of law: it is the contention undertaken by the legitimately constituted authority of civil society against external enemies, which distinguishes it from all other kinds of conflict. Whence the traditional definition given by St. Thomas Aquinas: “war is, properly speaking, carried on against external foes, being as it were between one people and another, whereas strife is between one individual and another, or between few people on one side and few on the other side, while sedition, in its proper sense, is between mutually dissentient parts of one people, as when one part of the state rises in tumult against another part.”5 War is, then, by definition a state of strife and not a simple quarrel between constituted societies who confront each other in the name of the common good.

This first look at the notion of war will enable us to better elucidate the signification of peace.


The Greek word for peace is eiréné (whence the name Irene) , and designates the state of a nation which does not find itself at war with another. It has been said that in the Greek world peace was but a short, or rather negotiated, interruption of war, bringing us back to the inevitability of war seen above. According to Plutarch, peace is “harmonization.”6 Peace treaties among the Greeks quite often associate peace and friendship, as Plato observed7: peace is not only a suspension of the state of war, but a preparation for the future, for it guaranties tranquility (esuchia), abundance, the cessation of pillaging, and finally a hope of prosperity.

Peace, because it designates the state of society that is not caught up in the maelstrom of war and its train of devastation, also designates a certain organization of relations between citizens, a sort of social peace, one might say, opposed to discord and strife. Thus, in the Greek city were to be found “guardians of the peace” with the mission of assuring that nothing disrupt the orderly functioning of public services.

Lastly, in a broader sense, eiréné designates the state of someone whose exterior tranquility is untroubled. Notably, what the Christian calls “interior peace” is not envisaged as such in Greek thought. It is in the Old Testament that the spiritualized notion of peace clearly appears: eiréné is the word that the translators of the Septuagint used to translate shalom, a term expressing “the state of one who lacks nothing and is undisturbed in his tranquility.”8 Whence it appears that it is in the religious domain that the notion of peace acquires its full scope. And so it is fitting to cite the Theologian so that he may tell us how he conceives of peace.

Saint Augustine, in a lapidary phrase, defines peace as the “tranquility of order.”9 In other words, peace designates the state of repose resulting when everything is in its place, be it in man when the passions are subject to the will fortified by grace, or in civil society when everyone’s will is oriented and ordered to the common good. St. Thomas Aquinas, with his accustomed precision, goes further, making of peace an act of the highest virtue: charity.10

External Peace, Internal Peace

The thought of St. Thomas incorporates and surpasses the Greeks’ analysis: peace is not only the absence of external strife; it is not even a simple accord between disparate wills; it necessitates as a condition the absolute concord of all the “affective motions” that can exist between men or even within one and the same individual.11 Peace of this kind requires that all sensible, affective movements of the soul be under the control of the will, and that the will in turn be docile to the movements of grace, of the Holy Spirit; in other words, that the will be animated by a love of God so as to order all its human acts. Such is the order that results in interior peace.

As for civic peace, it may be reasonably inferred that a perfect, lasting peace is not possible here on earth. At most the establishment of order among the wills of men may be the object of unrelenting efforts. Indeed, the duty of legitimately constituted authority is to assure this order within a society. However, when matters involve several fully constituted societies (namely, States), which by definition have no superior authority, then in the flux of circumstances, the established order that secures peace may be compromised: then it is the turn of conflict, of war, to enter in.

A Necessary Evil?

If the unbridled passions of men may occasion much strife and conflict within a society, how much more so when the conflict involves divers peoples and nations; assuredly, these conflicts will have far greater repercussions. It is these that are properly called war.

St. Thomas was one of the first to systematize the notion of just war: “In order for a war to be just,” he writes, “a just cause is required, namely that those who are attacked, should be attacked because they deserve it on account of some fault [against justice].”12 War thus envisaged is not contrary to the natural law. In other words, it is not intrinsically evil. Sometimes, in effect, it is the only way a State can guarantee its own security and assure its existence against the unjust aggression of a neighboring State, or maintain respect for important rights which cannot be relinquished without grave prejudice to the common good.13

Now, just as it is lawful for an individual to repel, even by violence, an unjust aggressor threatening one’s life (or that of one’s relatives or friends), or honor, or goods, all the more so is it lawful for a society.14 The authority in such a society has the right, and sometimes the duty, to employ the means of war so as to safeguard the common weal of this society. Note that this right extends not only to defensive war, but also offensive war, made necessary by the actions of a neighboring State whose ambitious machinations would constitute a genuine danger.15 This theory of just war is not contrary to the law of charity: supernatural love of God and neighbor can legitimize a conflict the goal of which is to re-establish the rights of one or the other.

War, then, is closely connected with the virtues of justice and charity, so much so that the Fathers of the Western Church did not hesitate to consider war a school of virtue and merit: thus, St. Ambrose, Bishop of Milan—a former military man it is true—places martial bravery among the virtues.16 The gentle St. Bernard writes that the soldier fighting in a just war merits heaven.17 The austere Tertullian, in his Apology, affirms for his part that the military state is in nowise incompatible with virtue and Christian holiness.18 If it is true that in certain texts, several of the Fathers of the early centuries of the Christian era condemn Christians who earn their living by war-craft, it is more because of the danger to faith that might be occasioned by fighting in close quarters with pagans, and obeying the emperor’s orders even when he was persecuting Christians.

Even though it may be just and elicit the noblest dedication in the service of Christian virtues, war nonetheless remains an evil the calamitous consequences of which often weigh heavily on men’s shoulders. The pagans themselves had no illusions about the nature of war: thus Horace astutely wrote that because of armed conflicts, “At all times, the multitude have been subjected to the stupidities of the great.”19

From Adam to Cain

For the theologian, in effect, war constitutes one of the most disastrous consequences of original sin. Before Adam’s fall, man lived in the profound peace resulting from the perfect harmony that existed among the faculties of a soul entirely subject to God—what St. Thomas Aquinas calls the state of original justice. In the perpetuation of the species, man’s vocation was to transmit this harmony to his posterity, which would have guaranteed peace among all. But original sin, contracted by every human being and the wounds of which still remain after baptism, erased in a certain way the Divine plan, leaving open the door to disorders and fights—in a word, to war.

Ferocious warfare has been present from the dawn of human history, and as the notion of the rights of others diminishes in the minds of men, the more they have recourse to violence to resolve disputes. In many cases, might unfortunately makes right. And when no moral principle is strong enough to resist the excesses of might, then the rights of the vanquished are trampled under by the victors: Vae victis, woe to the vanquished, as the ancient Romans coldly put it. Hence the urgency for societies to seek the establishment of true peace.

“Happiness Is Peace”

Because it results from good order among men within the same State or, at the international level, among different States, peace ought to be secured by those responsible for order within society. When it comes to the interior peace of a country, all those entities able to concur in reconciling the wills of men are mobilized to securing peace: the family first of all. Even though it is dependent on civil society, it is in the family that this basic tendency emerges, and where the minds and wills of children are educated in the true, the beautiful, and the good. Civil society in the natural order has the paramount duty to see to it that the social fabric, this ensemble of human interrelationships among men, should be regulated as well as possible: the civil authorities, but also the relevant intermediary institutions are in a position to see to a just distribution of goods, a source of social peace. Finally, the religious society, in the supernatural order, that is, the Church, is also a factor for peace, for she unceasingly sets before the eyes of civil society, by preaching and by daily example, the supernatural end to which everyone is actually called by God. At the international level, the difficulty of establishing a lasting peace comes about because of the absence on the natural level of a regulatory authority exercising adequate, uniform influence over all societies; recourse is made to various resolutions or international treaties for the purpose of guaranteeing or recovering peace. In this area, too, the role of the Church, the only international society in the supernatural order, is preponderant, and it is not by chance that the diplomacy of the Holy See is one of the most effective in the world.

Translated from “Guerre et paix,” Fideliter, Jan.-Feb. 2012, pp. 6-14.

1 The knowledge of one thing helps to understand its opposite, for it contains in itself the negation of the other. For example, the term cold rejects irreducibly anything related to the term heat; by striving to define cold the intellect invariably advances in the knowledge of heat, that is to say, what is not cold (St. Thomas Aquinas, Commentary on the Metaphysics, Bk. 3, lect. 4, no. 3.

2 Introduction, Elements of Philosophy (Téqui, n.d.), Vol. 1.

3 Fragments, No. 44, tr. G. W. T. Patrick (

4 Book XI, Ch. 26.

5 Summa Theologica, II-II, Q. 42, Art. 1.

6 De Alexandri magni fortuna, I, 6.

7 The Laws, I, 628 b.

8 A. Robert, Le Cantique des Cantiques (Paris, 1963), p. 145.

9 The City of God, Bk. 19, Ch. 13, § 1.

10 Summa Theologica, II-II, Q. 29, Art. 4.

11 R. P. Hugon, St. Thomas d’Aquin et la guerre (Téqui, 1916), Ch. 1.

12 Summa Theologica, II-II, Q. 40, Art. 1.

13 “...war is waged in order that peace may be obtained. Therefore, even in waging war, cherish the spirit of a peacemaker, that, by conquering those whom you attack, you may lead them back to the advantages of peace...” (St. Augustine, Letter 189 to Boniface, online at

14 Which constitutes what is called a moral or public person.

15 St. Robert Bellarmine, General Controversy: Of the members of the Church Militant in Opera Omnia (Naples, 1872), Vol. II, p. 327.

16 Migne, Patrologia Latina, Vol. 16, cols. 81-84.

17 Ibid., Vol. 182, col. 924.

18 Ibid., Vol. 1, cols. 295, 491.

19 Letters, Bk. 1, Letter 2.