Front Page Titles (by Subject) CHAPTER VII: Concerning the Subject-Matter of War for What Cause and in What Circumstances Is War Justly Waged? - Commentary on the Law of Prize and Booty
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CHAPTER VII: Concerning the Subject-Matter of War for What Cause and in What Circumstances Is War Justly Waged? - Hugo Grotius, Commentary on the Law of Prize and Booty 
Commentary on the Law of Prize and Booty, ed. and with an Introduction by Martine Julia van Ittersum (Indianapolis: Liberty Fund, 2006).
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Concerning the Subject-Matter of War for What Cause and in What Circumstances Is War Justly Waged?
Article I. What constitutes just subject-matter of war, in a causal sense, for voluntary efficient agents?
Article II. What constitutes just subject-matter of war, from the standpoint of attendant circumstances, for voluntary efficient agents?
Article III. What constitutes just subject-matter of war, in a causal sense, for subjects?
Article IV. What constitutes just subject-matter of war, from the standpoint of attendant circumstances, for subjects?[29′]
Corollary to Question VI. Can there be a war that is just for both parties?
Article I. With respect to voluntary agents?
Article II. With respect to subjects?
Let us consider next the following question: For what cause, and against whom, are wars waged? And let us devote the first part of our inquiry to what is properly termed the “cause of war,” although Aristotlea refers to the same concept as the “origin of war” and others, more specifically, as its πρόφασις [pretext or occasion].a
In this connexion, however, it should be noted that, although two types of belligerents have been mentioned above—the one type, voluntary, and the other (to which we applied the term “subjects”), instrumental, so to speak—the concept of “right” is not to be interpreted in the same way for the two cases. For subjects as such enjoy a right not absolutely, but in a relative sense, as the Scholastics have maintained. Indeed, in the strict sense of the term, a right pertains only to those who act voluntarily.d Furthermore, in order that a right may exist, it is necessary for volition to spring from an intellectual act of understanding, and that understanding must in turn be derived from truth itself. For the ancients were not unjustified in defining law as “right reason.” Those persons, moreover, who give the command for war, are properly admonished not to employ this last weapon of necessity unless such a course of action is based upon just cause.e Cicerof has said: “Those wars are unjust which have been undertaken without cause.”
Now, every right that we possess may be referred to one of four laws: the First, the Second, the Fifth, and the Sixth. For the Third and Fourth Laws, when interpreted from the standpoint of personal welfare, differ not at all from the First and Second, save only in the fact that the terms are reversed; while the Seventh, and all of the laws following thereafter, may be traced back to the Sixth (with the support, that is to say, of the Third Rule). Therefore, every [just] war must have its origin in one of four causes.
The first of these is self-defence, which is based upon the First Law. For, as Ciceroa observes, “. . . the act [of homicide] is not only just but even necessary, when it represents the repulsion of violence by means of violence.” Many statements to the same effect are to be found in the works of various authors.
A second cause is defence of one’s property, based upon the Second Law,b which makes it permissible not only to offer resistance but also to dispossess others. Moreover, the term “property” is to be understood not exclusively in a material sense, but as referring to every right, including that right to a good name which is justly the possession of virtuous persons and of which they ought by no means to be deprived.
A third cause—one that a great many authorities neglect to mention—turns upon debts arising from a contract or from some similar source. To be sure, I presume that this third group of causes has been passed over in silence by some persons for the reason that what is owed us is also said to be our property.c Nevertheless, it has seemed more satisfactory to mention this group specifically, as the only means of interpreting that well-known formula of fetial law:d “And these things, which ought to have been given, done or paid, they have not given, paid or done.” Plato, too, in the Alcibiades,e has said that wars are waged not only when one suffers oppression by violence, or despoliation, but also when one has been deceived. Yet again, the statement made by Senecaf may be cited: “Even cities bring charges against cities on the basis of services rendered.” Moreover, Baldusg expresses a similar view regarding pecuniary debt.
The fourth cause arises from wrongdoing, and from every injury—whether of word or deed—inflicted with unjust intent. Augustineh wrote: “Just wars, indeed, are wont to be defined as those which avenge injuries. Accordingly, that people or state should be attacked, which has neglected to punish evil conduct on the part of its citizens, or to restore what was unjustly taken away.”30 a]
Now, I wish to have it understood that these four causes listed as suitable subject-matter for war, are of the same character whether the war be private or public. In the case of public wars, however, the rights as well as the examples involved are more clear-cut; and private wars furthermore differ from public wars with respect to their efficient agents and their form. Nevertheless, they are not different in their subject-matter. The examples afforded by all living creatures show that force privately exercised for the defence and safeguarding of one’s own body is justly employed.a Furthermore, such force is also just when the purpose is defence or recovery of one’s property;b nor is it less so when employed for the collection of a debt.c Even private exaction of a penalty for crime is sometimes permitted: for example, when the penalty is imposed upon adulterers (in certain cases), robbers, rebels, or deserters.d It was for this reason that Tertulliane said: “Every man is a soldier against persons guilty of high treason, and against public enemies.” Nor is it by mere chance that the very lawsf expressly apply the term ultio [meaning primarily “vengeance”] to an “indulgence” that has been granted.[30 a′]
On the other hand, even as certain private wars are just by virtue of their cause, so public wars are unjust in the absence of due cause.g Thus Senecah complained: “We put a check on homicide and isolated cases of murder. But what of wars and the boasted crime of slaughter inflicted upon whole nations? Neither avarice nor cruelty recognize any bounds. [. . .] savage acts are committed in accordance with decrees of the Senate and the popular assembly, and the performance of deeds forbidden to private individuals is commanded by public authority.” Cypriana follows Seneca, saying: “When single individuals indulge in homicide, that is a crime. When homicide is committed by public authority, it is termed a virtuous act.” Herein lies the origin of the saying, “And law was given for [the service of] crime.” Accordingly, King Alexander was rightly included by the pirate among the latter’s partners in crime, if that ruler had no just cause for war against Asia; and in this same sense Lucanb called Alexander the “plunderer” of the world, while Senecac described him as a “robber.” A similar view may be taken of Crassus’ war against the Parthians.
New explanationTherefore, in both kinds of warfare, [public and private,] one must consider the causes involved. Of these there are four kinds, as we have pointed out: for the authorities who hold that there are three just causes of ward (defence, recovery, and punishment, according to their classification), fail to mention the not uncommon cause that arises whenever obligations are not duly discharged. Indeed, in so far as we are concerned with subject-matter, which is the same in warfare and in judicial trials,e we may say that there should be precisely as many kinds of execution as there are kinds of legal action. To be sure, legal judgements are rarely rendered in consequence of causes of the first class, since the necessity for defending oneself does not admit of such delay; but interdicts against attack properly fall under this head. The actions relating to property which we call civil claims, arise from the second kind of cause, as do also injunctions obtained in behalf of possession. The third and fourth classes give rise to personal actions, namely, claims to restitution, founded upon contract or upon injury.
Even as in the case of a lawsuit, however, so also in war, those causes which would justify the action taken by the plaintiff if they were genuine, serve instead to place the accused, or defendant, in the right if they do not have that just character which is claimed for them. For example, if a claim is presented against us for property that is our own, or if we are pressed to do something that we are under no obligation to do, or if it is demanded that we be given up for punishment when we are innocent, then, since the action against us is unjust, the defence must necessarily be just, in accordance with the First Law.
Furthermore, in these disputes involving war just as in the courts of law, not every rightful claim comes into existence before the process of execution. For the execution of one’s right in itself constitutes a right, a point already touched upon in our discussion of prize and booty.a
Accordingly, it is apparent from the foregoing comments that arms are not justly taken up for the sake of undue dominion or liberty,b whereas, for the purpose of rightfully retaining dominion and liberty already acquired, not even war should be shunned. Nevertheless, we should see to it (although this is a matter not so much of right as of discretion) that we do not rashly allow ourselves to be aroused by comparatively trifling injuries; for it is frequently less of a hardship to tolerate these, than it would be to endure the conditions that inevitably accompany war. We must steer clear of Charybdis without falling upon[30′] Scylla. Of a similar character is the forensic principle that it is not necessarily expedient to enter into litigation on every occasion when it is just to do so.
Our remarks on the subject of rights are applicable no less to allies than to the principal authors of a war,c since allies, too, should take care lest they involve themselves in a war that is not just. For they are not compelled to do so, inasmuch as unconditional contracts of alliance for war are invalid even from the legal standpoint.a It is for this reason that Abrahamb instructs his allies in regard to the justice of his cause; and Achilles, too, when he is about to aid the Greeks, is represented by the Latin poet Statiusc as first inquiring into the causes of the war, in these words:
Conclusion VI, Article ITherefore, in so far as concerns the persons who wage war voluntarily, that war has a just cause, wherein the said persons defend their lives or their property, or seek to recover the latter, or attempt to exact either payment of that which is due or punishment for wrongdoing.
Having settled this point, we shall have no difficulty in solving the second problem. For whatever is subject to a given action or suffers the effects thereof, is also customarily regarded as subject-matter of that action. An example of such subject-matter, pertinent to the discussion of war, is to be found in the party against whom war is waged, or in other words, the enemy, although the latter term has an active as well as a passive connotation. For, in the natural order, when the agent acts with calorific force, it follows that the passive recipient of the act is [relatively] cold;d and in precisely the same way, when it is evident that the belligerent waging a just war is acting with rightful force, it follows that the enemy against whom the just war is waged must necessarily be disposed in the opposite fashion. But we have already showne that the opposite of a right is a wrong. Therefore, in short, that party rightly becomes the passive subject of the said war, who is in his turn the perpetrator of a wrong.a Augustineb maintains that, “The injustice of the opposing party brings just wars upon him”; and the following pronouncement of the Emperor Leoc is in accord with the statement formulated by Augustine: ὁ γὰρ τοι̑ς ἀδικήσασιν ἀνταμυνόμενος οὑ̑τος δίκαιος ἐστίν; “For he is just who inflicts vengeance upon those who have done an injury.”1 The theologians,d too, expressing themselves in their own manner, declare that, “A party properly disposed to be the passive subject of war, is a party unwilling to give satisfaction.”
New explanationIn order to expound this portion of our argument more accurately, however, we must explain the concept of “wrongs.”
The expression “a wrong,” when opposed to “a right,” has three meanings, differentiated among the Greeks by the use of three separate terms, as we learn not only from the philosopherse but also from Ulpianf and Theophilus.g Again, the same distinction is clearly revealed in The mistius’ speech to Valens and in the words of Gylippus as quoted by Diodorus.h The Greek terms in question are, first, τὸ ἄδικον [wrong in the generic sense, that which is unrighteous or unjust]; secondly, ἀδίκημα [intentional wrongdoing] which manifests itself in either of two aspects, ὕβρις καὶ ζημία [wanton violence, and damage], and thirdly, ἀδικία [habitual and characteristic wrongdoing, injustice]. Hieraxi the philosopher, in his book on Justice, draws a neat distinction in regard to these three terms, observing that the first represents ἀποτἑλεσμα [completion or result], the second πρα̑ξις [action], and the third ἕξις [a habit or state of mind]; or in other words, an accomplished act or result,2 the performance of an act and the disposition to act, concepts which differ from one another just as a completed picture, the act of painting and the art of painting differ. On the basis of the first concept, the term ἄδικόν τι πράσσοντες [persons through whom wrong is effected], is applied; on the basis of the second, ἀδικου̑ντες [intentional wrongdoers], and on the basis of the third ἄδικοι [unrighteous persons]. Now every instance of ἀδικία [or habitual and characteristic wrongdoing] carries with it an element of ἀδίκημα [intentional wrongdoing], and the latter always involves τὸ ἄδικον [generic wrong]; but the reverse need not be true. For although these concepts differ not at all in so far as concerns the person upon whom the injury is inflicted, nevertheless they do differ with respect to the person who is committing the injury. Thus ἀδικία [habitual and characteristic wrongdoing] cannot occur otherwise than ἐκ προαιρἑσεως, “by premeditated choice,” whereas ἀδίκημα [intentional wrongdoing] sometimes occurs apart from premeditation, though always with antecedent knowledge and volition, or ἑκοντί [voluntarily], that is to say, in circumstances indicating that the agent understands against whom, in what way, and for what reason he is acting, so that his own volition is indeed involved in the act. On the other hand, τὸ ἄδικον [generic wrong]—which the Scholasticsa call “material injustice,” as opposed to formal injustice, while Baldusb describes it as “a factual fault,” distinguishing it thus from a conscious fault—can exist even in cases where the performance is not voluntary. “Mischances and mistakes” (ἀτυχήματα καὶ ἁμαρτήματα) both fall under this one head. To be sure, the latter type of wrong occurs when an act has its origin in the mind of the agent, though in such a way that he is somehow deceived; whereas mischances have some other origin, such as the fact that a weapon has slipped from one’s hand in crowded surroundings.
The ancient authorities on Roman lawa placed every instance of τὸ ἄδικον [generic wrong] under the general head of noxa [harm, injury, offence], and to those particular cases which were free of τὸ ἀδίκημα [intentional wrongdoing], they applied the term pauperies [loss or damage inflicted without volition]. An animal, in that it lacks the rational faculty, does not act with wrongful intent.3 In other words, neither ἀδίκημα [intentional wrongdoing] nor ἀδικία [habitual and characteristic wrongdoing] can be ascribed to animals; for animals are not endowed with volition, and far less do they possess the power of premeditated choice. Nevertheless, they can bring about a wrong. For “wrong” is a general term, applicable even in cases where the agent has not willed to do harm, as is indicated by the Aquilian Law.b
Perhaps, then, we shall not err if we say that the Greek phrases τὸν ἄδικόν τι πράττοντα, τὸν ἀδικου̑ντα, τὸν ἄδικον, refer respectively to the man who brings about a wrong, the man who acts with wrongful intent (facere iniuria) and the man who acts as an unrighteous person. In direct contrast with these phrases, we have the following expressions: δίκαιόν τι πράττειν, δικαιοπραγει̑ν καὶ δικαίως πράττειν, “to bring about[31′] what is right,” “to act with righteous intent” (facere iure), and “to act as a righteous person.” The above-mentioned concepts can also be adapted to conform with the phraseology of Marcianusc in his discussion of public prosecutions, so that the expression ἄδικόν τι πράττειν may be applied to one who brings about a wrong by chance, ἀδικει̑ν to one who does a wrong upon a sudden impulse, and ἀδικω̑ς πράττειν to one who acts habitually as a wrongdoer.
Accordingly I maintain that in treating of wrongs, or injuries,4 per-petrated by the enemy, we include under this head even injuries that are not voluntarily inflicted. This point may be clarified as follows.
Just as right has been shown to consist in that which accords with the First and Second Laws and also in that which accords with the Fifth and Sixth Laws, even so it may be shown that a wrong, or injury, is that which conflicts with the Second [Third]5 or Fourth Law, or with the Fifth or Sixth. For the laws of the first and second orders [Laws I and II, and Laws III and IV, respectively] are of an unmixed character, whereas those of the third order [Laws V and VI] have a mixed character and are therefore taken into consideration from two points of view [i.e. in connexion with both rights and injuries]. Thus, if any person threatens me with danger while he is dreaming (a supposition based upon actual occurrences, according to certain learned authoritiesa ) or, for that matter, while he is insane (as may happen at any time), there is no doubt but that I may rightly repel force with force, even to the point of slaying that person if no other way of ensuring my own safety is left open.b Yet such an assailant is not “acting with wrongful intent,” since at the time in question he is non compos mentis. It suffices that his act is in conflict with the Third Law. For, on the basis of the First Law, which charges me to have a care for myself even in preference to others, I have the right to ward off an act of that kind by any means whatsoever. As Senecac says, “Necessity, the great defence of human weakness, breaks down every law.” Indeed, as we observed at the outset,d necessity is the first law of nature. Similarly, a claim may be made upon property that is being held in good faith; that is to say, although the possessor is not voluntarily transgressing the Fourth Law, nevertheless the Second Law may properly be applied against him. Furthermore, it is possible that, owing to any one of several causes, the possessor of certain property may owe me a debt of which he himself is unaware. This situation may arise, for example, if he is an heir. In such circumstances, he is violating the Sixth Law by failing to pay the debt, and despite the fact that the violation is not voluntary, the benefit of that law should not be denied to me. For what could be more unjust than the loss of one person’s right because of another person’s error? Moreover, the foregoing observations are applicable in warfare just as they are in legal disputes.
Volition is taken into account only in connexion with the Fifth Law. Thus offences against this precept are not punished unless they were voluntarily committed. The reason for the exception lies in the fact that evil is repaid to the guilty person in proportion to the good seized by him in an unrighteous manner,a that is to say, through another’s ill; but no person can be judged to have enriched himself by means of another’s loss unless he was voluntarily the author of that loss; and therefore, not every instance of ἄδικον [generic wrong], but only ἀδίκημα or ἀδικία [intentional or habitual wrongdoing], can appropriately be viewed in this light. Later on, we shall see how these different forms of injury give rise to different modes of execution.b
For the present, it is clear that those persons who bring about injury in any way whatsoever are liable to prosecution in war, if they are liable to legal prosecution. For the law, according to Demosthenes,c is ἐπανόρθωμα τω̑ν ἑκουσίων καὶ ἀκουσίων ἁμαρτημάτων; that is to say, law corrects not only voluntary but also involuntary sins. Hence it follows that not merely persons who act with free-will, namely, principals and allies, but instruments, too, or in other words, subjects, are included under the head of “enemies.” For the subject, in the course of obeying commands, even if he does not “act with wrongful intent” (ἀδικει̑), at least “brings about a wrong” (ποιει̑ τὰ ἄδικα).d It is to [enemy] subjects that the following ritualistic phrases of the Romansa refer: (in the declaration of war) “I declare and make war upon the nations of the ancient Latins, and the men of the ancient Latins”; (in the inquiryb addressed to the people) “Whether they wished and ordered that war be declared upon King Philip and upon the Macedonians under his rule”; (and in the actual decreec mentioned by Cincius in his discussion of military affairs) “The Roman people have declared war against the Hermandulan nation and against the men of that nation.” Allies, too, are included in the formula,d “Let the enemy be that one, and whatsoever persons are within his garrisons.”
Another point that should be brought out, is this: the same principle that we laid down in connexion with rights holds good in regard to injuries, by a reverse process of reasoning; that is to say, a certain form of injury may be suffered during the very execution of a right. For he who resists a just execution, whether knowingly or ignorantly, causes an injury, since he either keeps back that which belongs to another or fails to do that which he is under an obligation to do, and since, moreover, he is also offending one whom he ought not to offend. Therefore, it is proper to proceed against a state in war, not only when that state itself commits the original injury, or when its magistrates do so on its behalf and by its authoritye (for we commit those acts, too, which we perform through another), but also when the said state protects citizens who have committed an injury; and it is proper to proceed in like manner against the citizens, in their turn, when they fight in defence of a state or magistrate that is the author of an injury.f In other words, inferior laws such as the Seventh and Eleventh (being derived, as they are, from the Third and Fourth Rules), when preferred to any of the first six[32′] laws, which are precepts of nature and of the law of nations (precepts based, that is to say, on the First and Second Rules), result not in the execution of rights but rather in the perpetration of injuries.a
Conclusion VI, Article IIIn the light of the facts above established, war is just for those who wage it voluntarily against individuals, or against a state, by whom, or by which, or by whose magistrate, an injury has been brought about;band it is also just when waged against a state that protects a citizen who is the author of an injury, or against the allies and subjects, in their capacity as such, of any opponent who brings about an injury.
Strictly speaking, as was noted above, the question of right does not arise where the actions of subjects are concerned; at least, it does not arise in so far as the source of these actions lies outside of the subjects themselves. For we have already intimated that the fundamental factor involved in this question is that of volition, which is directed by rational understanding, a point confirmed by the theologians; and instruments act in accordance with another’s volition. On the other hand, account must be taken of the fact that subjects, although they are instruments, are nevertheless human beings; but human beings—save of course for certain actions imposed by nature—do not act otherwise than of their own volition. How, then, shall we reconcile these statements?
New explanationWe may do so by arguing as follows: the will of subjects is ruled by the will of those who are in command, as is proper wherever instruments are concerned, but with the proviso that reason must not rebel, a proviso which in itself constitutes a phase of justice. Let us illustrate this argument by considering the character of slaves, a subject discussed at length by Aristotle.c Although some persons maintain that the slave is completely devoid of any capacity for virtue or even for justice, while others concede to him the same capacity for virtue as that which resides in a free man, the above-mentioned philosopher draws an admirable distinction, explaining that the virtue desirable in a slave is not the perfect form required of one who commands but rather the form necessary for servile purposes, and that this virtue is, moreover, very limited in extent. Inasmuch as slaves partake of the rational faculty, they may not be deprived of all claim to virtue; yet they cannot be placed on a level with free men, since they do not possess τὸ βουλευτικόν, “the deliberative faculty.” Accordingly, the point I set out to make is this: the slave does exercise reason in a partial degree, and in part he does not. The well-known verses of Homera are remarkably appropriate in this connexion:
Similarly, the slave is in a partial sense capable of virtue, and partially incapable thereof.
Furthermore, this same principle that is applicable to slaves, may be applied to other subject persons. For, as the author first cited [Aristotle]b asserts, the virtue of a child, οὐκ αὐτου̑ πρὸς αὐτόν ἐστιν, ἀλλὰ πρὸς τὸν τἑλειον καὶ ἔγούμενον; “is not personal and relative to the child himself, but relative rather to the individual who is set in authority over him as a more fully developed being.” The distinction in question also has a universal application, namely, between του̑ ἄρχοντος καὶ ἀρχομἑνον,a “the one who commands and the one who obeys”; and in this latter class, citizens, even when they are considered as individuals, are included. For citizens, according to Cicero,b are servants of the law. Furthermore, as Aristotlec explains, all that commands is a cause of virtue to that which obeys.d Tacituse has in mind the same distinction when he says: “The gods have assigned to the prince the supreme power of judgement; to the subjects, the glory of obedience has been left.” Thus, with respect to subjects, that contention is true which Carneades and the Academic philosophers have mistakenly applied to all persons, namely, that justice is a matter of opinion, οὐ φύσει ἀλλὰ νόμῳ, “based not upon nature but upon law,” inasmuch as it consists in compliance with the established institutions of the various nations. By the33 a] Peripatetics, this justice [characteristic of subjects] is described sometimes as “legal” and sometimes as “general,” because it can be ascribed to the same underlying principle as all the virtues, in so far as these are in conformity with some precept. The Scholastics add that, even as the phase of justice which relates to exchange takes its course between different parts of the whole, while distributive justice proceeds from the whole to the parts, so the phase to which we now refer consists in a process flowing from the parts to the whole.
Thus my original assertion—namely, that a war is not just even for subjects if it is repugnant to their reasonf —is equivalent to the opinion proclaimed by the theologiansg in the following terms: “Whatever does not have its origin in good faith, is sinful.” For, as the Scholasticsh observe, that act of volition is evil which is at variance with reason, even though reason be in error; and reason is indeed rebellious whenever it declares that the command of some state or magistrate, and consequently, the laws of the inferior orders, are in conflict with the laws of the superior orders and therefore unjust according to the Thirteenth Law. This point is convincingly confirmed by the rules from which the various laws are respectively derived. We are familiar with the saying, “It is better to obey God than to obey men,”a a maxim which Ambroseb adapts to our argument by offering this concrete example: “The Emperor Julian, although he was an apostate, nevertheless had Christian soldiers under him. When he said to those soldiers, ‘Advance your battle line for the defence of the state,’ they would obey him; but when he addressed them thus, ‘Advance your arms against the Christians,’ then they would recognize [only] the divine Commander.” For that matter, all of the jurists,c too, declare that one ought not to obey a prince who is manifestly issuing an unjust command. Furthermore, they maintain that, in cases of wrongdoing, no one is excused on the ground that he is acting under command,d since even a slave who obeys the order of a master engaged in piracy or in any like pursuit of a wrongful nature, is not immune from punishment.e Again, Senecaf has said: “For we may not command all things [from slaves]; nor are slaves compelled to obey in all things. They shall not execute commands adverse to the state, nor shall they lend a hand in any criminal act.” In a preceding passage, Senecag also points out that the relationship of a soldier to his general and that of a subject to his king, are the same as that of a slave to his master. Jeromeh [33 a′] adopts a similar view, saying, with reference to slaves and children: “They ought to be subject to their masters and parents only in those ways which are not contrary to the commands of God.” By the same token, those persons are not free from guilt who allege as an excuse the fear either of death or of property losses, while they lend themselves as accomplices to some act known or suspected to be unjust. For[33′] fortitude, the companion of justice, decrees that it is better to endure evils of any kind rather than to concur in evil, as Augustinea has observed in a similar connexion.
On the other hand, when reason is not opposed, even a war which in itself involves an injury is not unjust from the standpoint of subjects.b This principle (as Victoriac maintains in his refutation of Adrian’s opinion) is applicable even in the case of subjects who are doubtful as to the justice [of a war]. For we have laid down a ruled to the effect that “The authorities must be obeyed”; and no one may depart therefrome save through an application of the Thirteenth Law, whereas a person in doubt makes no such application. Neither is any obstacle presented by the precept, “Commit no act concerning which you are doubtful”; for he who is in doubt as to the justice or injustice of a war proclaimed by command, does not forthwith conceive an additional doubt as to whether or not obedience is due in doubtful cases. Moreover, while the foregoing argument is valid even in cases where reason fails in the sense that no definite decision is reached, the same argument will have far greater force when the reason of the subject favours the war, as it does quite properly in a great many instances.
New explanationFor right is based upon fact. And facts—that is to say, specific facts—are learned neither through art nor through science, which are of a purely universal nature. Again, very few facts are discernible through the senses, since we cannot be in more than one place at one particular time, and since the senses perceive only those things which are very close at hand. Yet there is no other way of attaining to true knowledge. Impelled thus by necessity, human reason has fashioned for itself certain rules of probability, or τω̑ν εἰκότων, for passing judgement in regard to facts. These rules consist of various προλήψεις, or (to use the Latin term) praesumtiones [preliminary assumptions], which are not fixed and unchangeable like scientific rules but rather of a character considered concordant in the greatest possible degree with nature; that is to say, on the basis of what commonly occurs, conclusions of a similar trend may be drawn.a In this sense, a question of fact may be called conjectural. For, among the proofs which we accept in forming judgements, there is not one that is necessarily conclusive; on the contrary, all of them are derived from the aforesaid preliminary assumptions ὡς ἐπὶ τὸ πολύ, “based on what commonly occurs.”b 
Now, the primary principle among these assumptions of fact would seem to be our supposition that those inclinations which are in the highest degree natural (such as the inclinations toward the True and toward the Good), as well as the others derived therefrom, exist inherently in some measure within all things. Here we have the source of such concepts as assured belief in posterity, the beneficial nature of property ownership, the credibility of witnesses or documents, and the gravity of oaths. Moreover, not only does the rule of charity instruct us to think well of private individuals,c but also (and this is a particularly important point) both reason and Holy Writd forbid disparagement of magistrates. For magistrates have the support of the weightiest preliminary assumptions, partly because of the oath they customarily take, partly as a result of the general consent expressed by the state and the testimonial of confidence given by the citizens, considerations of such a nature that anyone holding a different opinion in regard to these officials would not only be charging the magistrates themselves with treachery but would also condemn a vast multitude of persons on a charge of folly. For all such charges would be contrary to those natural impulses which I have called “inclinations.” Furthermore, if anyone who practises a particular profession or art is properly regarded as expert and painstaking in his special field,a why, pray, should not magistrates be considered to have judged wisely (inasmuch as they are the Priests of Justice) concerning the cause of a war? For it is the function of a good magistrate to formulate such judgements. And when the magistrates hold that things justifying entry into war have befallen the citizens, why should not faith be placed in those authorities, as in persons who speak the truth?b Yet again, why should it not be right to believe that the laws of an inferior order are in agreement with the higher laws, and that the commands of the magistrate are identical with the commands of God,c whenever no obstacle exists to preclude such a belief? In short, subjects subordinate to a given state or magistrate occupy a position analogous to that occupied by children and slaves, who are subject respectively to the solemn patria potestas and to the power of the master.
Nevertheless, when we append the condition that reason must not rebel, it should be understood that we are referring to reason guided by the weighing of probabilities. For neither crass ignorance (for example, ignorance of the natural law) nor lack of knowledge regarding a fact which anyone ought to have known, constitutes an excuse for sinning.d There are certain things, indeed, of which one cannot be blamelessly ignorant; and, according to the teachings of both the jurists and the philosophers,e this very condition of blameworthy ignorance merits punishment.
But we have demonstrated the validity of the opinion which tends not a little to placate the consciences of many persons. Augustinea has expounded this opinion in the following terms: “Therefore, the just man, if he should by chance be serving as a soldier even under an impious king, may righteously wage war at the latter’s command, provided that, while he observes the dispositions of rank established to maintain peace within the state,7 it is certain either that the order issued to him is[34′] not contrary to the law of God, or, at least, uncertain that the order does conflict with God’s law; so that the king may perhaps be held responsible for an unjust command while the soldier is shown to be innocent because of his rank as one who serves.”
Conclusion VI, Article IIIWe ourselves shall state our conclusion thus: For subjects, that war has a just cause which is ordered by a superior, provided that the reason of the subjects is not opposed thereto after weighing the probabilities.b
Through this same process of reasoning, we arrive at the answer to another question, namely: what persons may justly be attacked in war by subjects? In the [Civil] Law,c the enemies of the Romans are defined as those against whom the Roman People have decreed war. Indeed, in all parts of the world, subjects justly wage war upon those against whom war is ordained by the state or magistrate of the said subjects, save in cases conflicting with the limitation explained abovea [i.e. cases in which reason rebels after the probabilities have been weighed].
At this point, however, we are confronted with a difficult problem. For we have already said that in an essentially unjust war the subjects, though acting in ignorance, are nevertheless “bringing about a wrong”8 and are therefore rightly attacked in war; yet in the present connexion we say that those same subjects, when ignorant, “act as righteous persons” when they wage war; but he who “acts as a righteous person” is at the same time “acting with righteous intent” and “bringing about what is right”; now, a single act cannot be both right and wrong, since these two concepts are diametrically opposed to each other, and on the other hand, it is certain that a given individual cannot be acting both “as a righteous person” and “as an unrighteous person,” since both these forms of conduct relate to the disposition of the agent, in which contrary feelings regarding a given matter cannot be entertained simultaneously. Nevertheless, it is possible for the same person to bring about a wrong and a right effect at one and the same time, though not with respect to a single object. For actions which proceed from an identical source can have an opposite effect upon different objects. For example, clay is hardened by the action of the selfsame fire that softens wax. Similarly, when a subject is waging by lawful authority a war that is in itself unjust, the effect constitutes a wrong in relation to the party against whom the war is directed; yet it represents a right from the standpoint of the party who gives the order, and not merely a right, but justice itself. For (as we indicated above) virtue in the subject must bear a relation to the authority in command. The following argument will clarify this point: any act whose omission would be characteristic of an unrighteous person, is characteristic of a righteous person when it is not omitted; and a subject would be “acting as an unrighteous person” if, when his magistrate gave orders for a war not known by the subject to be unjust, the latter should refuse to carry on that war; moreover, he would be sinning not only in a civic capacity but also against his conscience.a For, as Augustineb  explains, “when a soldier, acting in obedience to the power lawfully set over him, slays a man, that soldier is not guilty of homicide by any law of his own state; on the contrary, if he has failed to act thus, he is guilty of betrayal and contempt of sovereign authority. If, however, he had committed this same act of his own accord and by his own authority, he would have become liable to the charge of shedding human blood. Thus he will be punished for failing to perform, when bidden to do so, the very act that he is punished for performing unbidden.” Hence it follows that a subject “acts as a righteous person” when waging a war that he does not regard as unjust, even if wrong is thereby inflicted upon another.c
Nor is there any reason to be surprised at this conclusion. For the judge who sentences an innocent prisoner when the latter has been convicted by legal proofs, is also “acting as a righteous person,” since he is doing that which it would be sinful for him not to do; yet the wrong done to the innocent person is not lessened by these circumstances. A similar statement could be made in regard to the person executing a death sentence, inasmuch as he is bound to execute that sentence unless he is convinced that the command to do so is unjust. Despite the fact that such cases admit of an occasional error in reasoning, this possibility of error does not vitiate the justice of the act involved, since (as the Scholasticsd have taught) the volition attached to erring reason is wicked only in those instances where knowledge is obligatory. Furthermore, there are many just causes of war whose public disclosure is inexpedient,e nor is it fitting that a private individual should be curious in such a situation; for if a delay were permitted for each person’s examination of the cause in question, opportunities to build up resistance would be afforded to the enemy.
In the foregoing observations, we have an explanation of the ruling, “He inflicts harm who commands that it be inflicted, but he is guiltless who must necessarily obey”;a and of this other ruling, too: “If a free man has inflicted a wrong with his own hand by order of another,[35′] action may be brought against the party who gave the command, provided that the latter had the right of command; but if he did not have this right, the action must be brought against the party who committed the act.”b The same principle may be applied to explain the words of Augustine:c “the just man shall give no special thought to any consideration other than this, that the person undertaking the war is one who has a lawful right to wage war.” Thus Panormitanusd appends a shrewd restriction to Hostiensis’e pronouncement against war, in stating that a war is presumed to be just when it has been declared by a superior power. Not only in the opinion of Panormitanus, but also by unanimous agreement among all of the theologians and teachers of canon and civil law,f in every case of this kind, subjects fight justly and are exempt from any charge of murder.
Conclusion VI, Article IVIn short, the contention of these authorities is equivalent to the conclusion which we shall formulate in the following terms: For subjects, that war is just which is waged against an opponent whom their superior has ordered them to attack in war, provided that the reason of the subjects is not opposed thereto after weighing the probabilities.
The difficult and much-mooted question of whether or not it is possible for a war to be just on both sides,g is susceptible of clarification on the basis of the comments already made. For there is no doubt but that the remaining requisites of justice—for instance, those relative to authority, mode of warfare, or intent—can be present in both belligerents, so that the whole of the difficulty lies in the matter with which we have just dealt. Indeed, it does not seem possible that one might justly resist a person seeking to obtain his rights, in the same manner as if one were resisting the perpetrator of a wrong. Thus it becomes necessary to draw a distinction between subjects and persons in command.
For if we are referring to the state or magistrate authorizing a war, we are more likely to find both belligerent parties in the wrong than we are to find right on both sides. Take for example a case in which a debt of five is owed, and one party seeks to collect ten while the other offers no payment whatsoever. For we have here a situation identical with that created by two mutually contradictory statements, which may both be false at one and the same time whereas they cannot both be true simultaneously. Of course, it is possible for princes to fall into error either of law or of fact,a and the error may be excusable; but if such an inadvertent mistake should occur during a judicial trial, that would not enable us to say any more truly that the suit was justly litigated. For in the case of voluntary agents it is necessary, if they are to be regarded as acting justly, that their action shall in itself be in conformity with the laws. ThereforeArticle I of Corollary, in so far as voluntary agents are concerned, there can be no war that is just for both parties.
On the other hand, if we refer exclusively to those persons who serve in warfare, there is nothing to preclude the possibility of a war that is just on both sides. For the issue of justice as a whole turns not upon a single fact, but rather upon the conflicting orders and opinions of the various persons in command; and furthermore, the conflicting acts of different commanders do not necessarily invalidate each other, just as it is not impossible that contrary opinions, both of a credible nature, may occur to different men in regard to one and the same matter.
The same theme is touched upon in the following quotation from Cicero:b “Indeed, a certain confusion prevailed: generals of the greatest renown were pitted against each other. Many persons were in doubt as to what would be the best course: many, as to what would be expedient for themselves; many others, as to what would be seemly; and some were doubtful even as to what would be lawful.” Such, then, are the persons referred to in various passages as “Just enemiesjust enemies,” namely, those who do what they do at the command of a superior power. Consequently, within a state tyrants and rebels are not classified as just enemies, and outside the bounds of any state brigands and pirates are excluded from this classification, although the reason for excluding these groups has not hitherto been given sufficient consideration.
Article II of CorollaryAll of the theologians and juristsc agree, however, in accepting this principle: In so far as subjects are concerned, a war can be just for both parties: always provided, of course, that the war be preceded by a command against which reason does not rebel after the probabilities have been weighed.[36′]
[a. ]Politics, I. vi [I. ii. 18].
[a. ]Polybius, Histories, III [vi].
[b. ]Chap. ii, at end, supra, p. 50.
[c. ]Beginning of Chap. vi, supra, pp. 92–94.
[d. ]Arist., Nic. Ethics, V. x [V. viii. 1]; Institutes, I. i, at beginning.
[e. ]Panormitanus, On Decretals, II. xxiv. 29, n. 12; Vict., De Jure Belli, 21.
[f. ]The Republic, III [xxiii. 35]. Also in Isidore [Etymologies, XVIII. i. 2–3].
[a. ][For Milo, iv. 9.]
[b. ]Dig. XLIII. xvi. 3, § 9; Decretum, II. xxiii. 2. 1.
[c. ]Dig. L. xvi. 91.
[d. ]Livy, I [xxxii. 5]. Add Institutes, IV. vi. 1.
[e. ][p. 109 a, b.]
[f. ]On Benefits, III. vi.
[g. ]On Dig. I. i. 1.
[h. ]Qu. on Heptateuch: On Joshua, VI, qu. 10, cited in Decretum, II. xxiii. 2. 2.
[a. ]Dig. I. i. 3; Code, IX. xvi. 2; Dig. XLVIII. vi. 11; Decretals, V. xii. 18; Constitutions of Clement, V. iv.
[b. ]Sylvester, on word duellum, iii and on word bellum, Pt. II. x, xi, xii; Dig. XLIII. xvi. 1, § 27; Decretals, II. xiii. 12; Code, VIII. iv. 1; Dig. XLIII. xxiv. 7, § 3; and ibid. 22, § 2; Exodus, xxii. 2; Decretals, V. xii. 3.
[c. ]Dig. XLII. viii. 10, § 16; Innocent, On Decretals, II. xiii. 12, n. 8.
[d. ]Code, IX. ix. 4; see especially Vάzquez, Cont. Post. IV. viii [Ill. Cont. Pt. II, bk. I, chap. viii]; Code, I. iii. 54; ibid. III. xxvii, whole title.
[e. ]Apology [ii. 8].
[f. ]Code, III. xxvii. 1, § 1; ibid. XII. xl. 5 [§ 1a].
[g. ]Sylvester, on word bellum [Pt.] I. iv.
[h. ]Epistles, xcvi [xcv. 30].
[a. ]Epistles, II. ii [I. vi].
[b. ][The Civil War, X. 21.]
[c. ]See Seneca, On Benefits, I. xiii.
[d. ]Baldus, On Code, III. xxxiv. 2, n. 71 [n. 77], and the theologians; also Matthaei, De Bello Justo.
[e. ]See infra, on forms [in war, Chap. viii].
[a. ]See Exposition of Art. I, Concl. II, supra, pp. 68 ff.
[b. ]Vict. [De Jure Belli], 11, 12; Arist., Politics, VII. iii [VII. ii. 10].
[c. ][Trovamala], Summa Rosella, word bellum, n. 10; Sylvester [on word bellum, Pt. I.] ix [x]. 4.
[a. ]Innocent, On Decretals, II. xxiv. 29; Matthaei, De Bello Justo, in Req. 1.
[b. ]Genesis, xiv. 14.
[c. ]Achilleid, II [47–8].
[d. ]Arist., On Generation and Decay, I. vii.
[e. ]At end of Chap. ii, supra, p. 50.
[a. ]Vict. [De Jure Belli], 13.
[b. ]On the City of God, IV [xv].
[c. ][Constitution lxi.]
[1. ]Grotius’s Latin translation of Leo’s pronouncement is perhaps a little stronger than the Greek text warrants. The latter refers to self-defence rather than to vengeance, and literally translated into English would run as follows: “For he who defends himself against those who have done him injury, is a just man.” But here, as in other cases not specifically noted where there is a discrepancy between the Greek and Latin texts, the present translation of the Commentary is based upon the Latin.
[d. ]Cajetan, On II–II, qu. 40, art. 1.
[e. ]Arist., Nic. Ethics, V. x, xi [V. vii. 7] and Rhetoric, I. xiii.
[f. ]Dig. XLVII. x. 1.
[g. ]Institutes, IV. iv, at beginning.
[h. ]Library of History, XIII [xxix].
[i. ][In Stobaeus, Florilegium, IX. 58.]
[2. ]Simply opus (a work performed) in the Latin, interpreted by this expanded English phrase on the basis of the context.
[a. ]Th. Aq. II–II, qu. 59, art. 2.
[b. ]On Code, VIII. iv. 1.
[a. ]Dig. IX. i. 1.
[3. ]facere iniuria (to act by way of wrong); Grotius’s argument in the immediately following paragraph and in subsequent passages of this chapter clearly calls for some such interpretation of the phrases facere iniuria and facere iure (to act by way of right, i.e., to act with righteous intent).
[b. ]Dig. IX. ii. 5, § 1.
[c. ]Dig. XLVIII. xix. 11, § 2.
[4. ]These three English words are a translation of the single Latin word iniuriam, sometimes best translated as “a wrong” (e.g., in the immediately preceding discussion of right as contrasted with wrong), but commonly rendered as “injury” (the translation usually adopted for Grotius’s more general statements).
[5. ]Secunda was obviously written by a slip of the pen for tertia. Cf. appendix A.
[a. ]Bartolus, On Dig. I. i. 3, n. 1 [n. 5]; Baldus, On Code, VIII. iv. 1, n. 50 [n. 38].
[b. ]Constitutions of Clement, V. iv.
[c. ]Declamations, IX [Controversies, IX. iv. 5].
[d. ]Laws I and II, supra, p. 23.
[a. ]See Law V in Chap. ii, supra, p. 29.
[b. ]In forms [on war, Chap. viii].
[c. ]Cited in Dig. I. iii. 2.
[d. ]Arist., Nic. Ethics, V. xii [V. ix. 11].
[a. ]Livy, I [xxxii. 13].
[b. ]Livy, XXXI [vi. 1].
[c. ]Gellius, XVI. iv .
[d. ]Livy, XXXVIII [xlviii. 10] and passim.
[e. ]See infra, in forms [on war, Chap. viii].
[f. ]Th. Aq. II–II, qu. 104, art. 5; Vάzquez, ii and xxvi. 29.
[a. ]See Law XIII, supra, pp. 49–50.
[b. ]See Plato, Alcibiades, I [p. 109].
[c. ]Politics, I, last chap. [I. ii. 13–23]; id., Nic. Ethics, VIII. xii [VIII. x. 4].
[a. ][Odyssey, XVII. 322 f.]
[6. ]The two passages ascribed here to Homer appear to be an unduly expanded paraphrase of a single passage from the Odyssey (XVII. 322–3). Evidently Grotius was not only quoting from memory at this point, but was also confused by variant readings of the two lines in question. The Loeb edition of the Odyssey has adopted the reading ἀρετη̑ς (worth) instead of νόου (mind) in the first line, and translates the entire passage as follows: “for Zeus, whose voice is borne afar, takes away half his worth from a man, when the day of slavery comes upon him.” On the other hand, Plato, in quoting the same passage (On Laws, VI, p. 777a), uses νόου, not ἀρετη̑ς. Grotius expands Homer’s statement by making it refer to both the worth (or virtue) and the mind of slaves.
[b. ][Politics, I. v. 9.]
[a. ][Ibid. I. v. 6.]
[b. ]For Cluentius [liii. 146].
[c. ][Politics, I. v. 5–6.]
[d. ]Colossians, iii. 20, 22; Titus, vi. 1 [iii. 1]; Ephesians, vi. 1; Romans, xiii. 1.
[e. ]Annals, IV [VI. viii].
[f. ]Angelus, [de Clavasio], Summa, on word bellum, n. 8.
[g. ]Romans, xiv. 23; Vict. [De Jure Belli], 23.
[h. ]Th. Aq. I–II, qu. 19, art. 4. See also Arist., Nic. Ethics, VI. ii .
[a. ]Acts, v. 29; Decretum, II. xi. 3. 93; Ecclesiastes, viii. 1.
[b. ]In Decretum, II. xi. 3. 94.
[c. ]Vάzquez, Ill. Cont. ii. 12.
[d. ]Dig. XLVII. x. 11, §§ 3 and 5.
[e. ]Dig. XLIV. vii. 20; ibid. L. xvii. 157 and Peter Faber thereon.
[f. ]On Benefits III. xx.
[g. ]Ibid. viii [xviii].
[h. ]On Ephesians [On Titus, ii], cited in Decretum, II. xi. 3. 93.
[a. ]On the City of God, II [I. xviii], cited in Decretum, II. xxxii. 5. 3.
[b. ]Ayala, De Iure et Officiis Bellicis, I. ii. 33.
[c. ][De Jure Belli] 31.
[d. ]See Rules IV and VI, in Chap. ii, supra, pp. 40, 45. Add Second Informal Exposition of Art. I, Concl. I, in Chap. iii, supra, pp. 58–60.
[e. ]Th. Aq. II–II, qu. 64, art. 3 [art. 6], ad 3.
[a. ]See Th. Aq. I–II, qu. 105, art. 2, ad 8; id. II–II, qu. 70, art. 2; Vάzquez, Ill. Cont. xiv. 2; Doctors, On Decretals, II. xxiii. 2.
[b. ]Arist., Nic. Ethics, I. i. [I. iii. 4]; Dig. I. iii. 3.
[c. ]Dig. XVII. ii. 51.
[d. ]Ecclesiastes, x. 17; Exodus, xxii. 28; 1 Peter, ii. 17.
[a. ]Bartolus, De Testibus, 86 .
[b. ]Dig. I. iii. 20, and Baldus and Doctors thereon.
[c. ]Code, I. xiv. 12; Panormitanus, On Decretals, I. iii. 5; Felinus, On Decretals, I. iii. 8.
[d. ]Th. Aq., II–II [I–II], qu. 76, arts. 1, 2, 3, 4.
[e. ]Arist., Nic. Ethics, II. vii [III. v. 2–3]; Dig. XXII. vi. 6.
[a. ]Against Faustus, XXII. lxxiv [lxxv], cited in Decretum, II. xxiii. 1. 4. Agrees with Innocent, On Decretals, II. xxiv. 29, n. 1.
[7. ]Reading si civicae pacis ordinem servans, the correct wording of the passage cited from Augustine, and not si vice pacis ordinem servans (. . . provided that, while he observes the claims of rank rather than those of peace . . .), the phrase actually employed here by Grotius. Since the same passage is correctly quoted in Grotius’s own treatise On the Law of War and Peace (II. xxvi. 4. 3), and since the similarity in sound between the two phrases suggests that the alteration in the Commentary may have been the unintentional result of an aural misunderstanding (such as could have occurred in the process of dictating the quotation from Augustine), the wording of the Contra Faustum has been followed in the English translation.
[b. ]Sylvester, on word bellum [Pt. I.] ix [x]. 3.
[c. ]Dig. XLIX. xv. 24.
[a. ]See discussion of Art. II of Concl. VI, supra, pp. 114 ff.
[8. ]Grotius’s argument here must be read in the light of his general discussion of certain concepts relating to right and wrong; cf. collotype pp. 30′–31′.
[a. ]Th. Aq. I–II, qu. 96, art. 4; Soto, De Iustitia et Iure, I, qu. 6, art. 4.
[b. ]On the City of God, I. xxvi, cited in Decretum, II. xxiii. 5. 13.
[c. ]Sylvester, on word bellum [Pt.] I. ix [x]. 4.
[d. ]Th. Aq. I–II, qu. 19, art. 6.
[e. ]Vict., De Jure Belli, 31; Cajetan, in Summula Peccatorum, words bellum dubium.
[a. ]Dig. L. xvii. 169.
[b. ]Dig. IX. ii. 37; add Glossators, On Dig. L. xvii. 167, § 1.
[c. ][Questions on Heptateuch,] VI. x, On Joshua, cited in Decretum, II. xxiii. 2. 2.
[d. ]On Decretals, II. xxiv. 29, n. 13.
[e. ]On Decretals, V. xxxiv. 1; add Sylvester, on word bellum [Pt.] I. iv and v.
[f. ]Vict. [De Jure Belli], 25, 31; Innocent, On Decretals, III. xxxiv. 8; Castrensis, On Dig. I. i. 5, n. 9; Ayala, I. ii. 31.
[g. ]See Piccolomini, Philosophia Civilis [Della Filosofia Naturale], VI. xxi.
[a. ]Vict., De Jure Belli, 59.
[a. ]Lucan [The Civil War, I. 126 f.].
[b. ]For Marcellus [x. 30].
[c. ]Vict. [De Jure Belli], 32; Covarr., On Sext, rule peccatum, Pt. II, §§ 9 and 10; Soto, De Iustitia et Iure, V. qu. 1, art. 7; Vάzquez, ix. 16 .