The Law of War and Peace (1625)

by Hugo Grotius

On Promises

I.     Refutation of the opinion that by the law of nature a right does not arise from promises.
1.   THE order of our work has brought us to the obligation which arises from promises. Here we find ourselves at once opposed to Francois de Connan, a man of exceptional learning. For he maintains the opinion that according to the law of nature, as well as the law of nations, no obligation is created by those agreements which do not contain an exchange of considerations; that nevertheless such agreements are honorably carried out if only the matter is of such a nature that it would have been honorable and consistent with some other virtue to fulfill them even without the promise.

2.   Furthermore in support of his opinion he brings forward not only the statements of jurists but also these reasons, that the individual, who rashly believes a person that makes a promise without any reason for it, is not less at fault than the person who has made a worthless promise; then, that the fortunes of all would be greatly imperilled if men should be bound by a mere promise, which proceeds often from the love of display rather than from a purpose, or from a purpose, indeed, but a trivial and ill-considered purpose; finally, that it is just to leave something to the honesty of each person and not to exact fulfillment according to the necessity of an obligation; that it is disgraceful not to fulfill promises, not because the act is unjust, but because it reveals the worthlessness of the promise. He cites also the testimony of Cicero, who said that promises ought not to be kept if they are of no advantage to those to whom you have made the promise, or if they are more harmful to you than they are advantageous to him to whom you made the promise.

If, however, freedom of action is no longer possible, Connan thinks that there is due to a man not the thing which was promised, but only what is to his interest; that, for the rest, the force which agreements have they do not derive from themselves but from the contracts in which they are contained or to which they are added, or from the delivery of the property; and that under such conditions on the one side actions lie and on the other exceptions are filed and recovery forbidden. Those agreements, in truth, which have the force of, an obligation according to the laws, such as those containing stipulations, and certain others, derive their force from the beneficence of the laws, which have the effect of rendering obligatory that which in itself is only honorable.

3.   Now this opinion, in the general terms in which it is stated by Connan, cannot stand. For, first, it follows therefrom that agreements between kings and different peoples have no force so long as no part of such agreements has been carried out, especially in the regions where no set form of treaties or guaranteed engagements exists. Again, no reason can, in fact, be found why laws, which are a sort of common agreement of the people and are so characterized by Aristotle and Demosthenes, should be able to add the force of an obligation to agreements, while the desire of each individual striving in every way to bind himself is unable to add such force, especially in cases where the civil law offers no impediment.

There is the further fact that ownership of property can be transferred by an act of will which is sufficiently manifest, as we have said above. Why then, since we have equal right over our actions and over our property, may there not be transferred to a person also the right to transfer ownership (this right is less than ownership itself) or the right to do something?

4.   To these considerations we must add the accordant opinion of wise men. For just as the jurists say, that nothing is so in accord with the law of nature as that the wish of the owner should be held valid when he desires to transfer his property to another, in like manner it is said that nothing is so in harmony with the good faith of mankind as that persons should keep the agreements which they have made with one another. Thus the edict concerning a promised payment of money, when on the part of the person who made the promise no cause for the debt except the agreement had preceded, is said to agree with natural justice. Paul the jurist also says that ‘the man who according to the law of nations ought to pay, and on whose good faith we have relied’ – and here the word ‘ought’ implies a kind of moral necessity – ‘is indebted by the law of nature.’

Furthermore, that is not to be admitted which Connan says, that we are considered to have relied on one’s good faith only when action according to the agreement has commenced. For in that passage Paul was treating of an action to recover money wrongfully paid, which is void if the money was paid in accordance with any agreement whatsoever, for the reason that both according to the law of nature and according to the law of nations the obligation to pay existed before any payment was made, though the civil law, in order to remove occasions for lawsuits, did not furnish support.

5.   Cicero, moreover, in his treatise On Duties, attributed to promises such force that he calls good faith the foundation of justice. Horace calls her the sister of justice, while the Platonists often designate justice by the Greek word meaning ‘truth,’ which Apuleius has translated’ fidelity.’ Simonides, in fact, explained that justice consists not only in returning what had been received but also in speaking the truth.

6.   Now in order that the matter may be properly understood, we ought carefully to distinguish the three ways of speaking concerning things yet to come, which either are under our control, or, according to our expectation, soon will be.

II.     That bare assertion does not create a binding obligation.
The first of these three modes of speech is an assertion, setting forth a present intention concerning something in the future. That this assertion may be free from fault, the true expression of the opinion held at present is required, but not the continuance of that opinion. The human mind, in fact, has not only a natural power, but also a right, to change its opinion. If there is anything wrong in the change of opinion, as at times happens, this is not inherent in the change, but comes from the subject-matter, as, for example, because the first opinion was better.

III.     That by the law of nature a promise is binding, but that no legal right is thereby gained by another.
In the second mode of speech the intention shapes itself in respect to future time with a sufficient manifestation to show the necessity of continuance. This also may be called a sort of promise, which, without regard to the civil law, is binding either absolutely or under conditions, but gives no right, properly speaking, to the second party.. In many ‘cases it happens that a moral obligation rests upon us, but no legal right is acquired by another, just as becomes apparent in the duty of having mercy and showing gratitude; similar to these is the duty of constancy or of good faith. So in the face of such a promise the property of the one promising can be retained, and the promisor cannot be compelled by the law of nature to keep faith.

IV.     What the kind of promise is by which a second party acquires a legal right.
1.   In the third way of making a promise, such a purpose as that just mentioned is manifested by an outward sign of the intent to confer the due right upon the other party. This is a perfect promise, and has an effect similar to alienation of ownership. It is, in fact, an introduction either to the alienation of a thing or to the alienation of some portion of our freedom of action. To the former category belong promises to give; to the latter, promises to perform.

A noteworthy proof of what I am saying is furnished by the Scriptures, which teach us that God Himself, who cannot be bound by any established law, would act contrary to His nature if He did not make good His promises (Nehemiah 9:8; Hebrews 6:18, 10:23; 1 Corinthians1:19 [1:9], 10:13; 1 Thessalonians 5:24; 2 Thessalonians3:3; 2 Timothy2:13). From this it follows that the obligation to perform promises arises from the nature of immutable justice, which in its own fashion is common to God and to all beings possessed of reason. In addition to this there is the judgement of Solomon:

      My son, if thou art become surety for thy neighbor,
      If thou hast stricken thy hand with a stranger,
      Thou art snared with the words of thy mouth,
      Thou art taken with the words of thy mouth.

Hence a promise is called by the Jews ‘a bond,’ and is compared to a vow (Numbers 30:4, 5, 6).

Similar is the origin of the word for promise in Greek, as is noted by Eustathius on the second book of the Iliad: ‘The one to whom a promise is made in some way captures and binds the promisor.’ The thought is also well expressed by Ovid in the second book of the Metamorphoses, where the promisor says to the one to whom he has given his promise, ‘My word has become yours.’

2.   With these considerations in mind we shall have no difficulty in replying to the arguments of Connan. For the sayings of the jurists about mere promises have in view the custom introduced by Roman law, which required a formality as the indispensable sign of a deliberate intent. And we do not deny that there are similar laws among other peoples. Seneca, when speaking of human law and a promise not made in proper form, says: ‘What law obliges us to perform what we have promised to any one?’

3.   Naturally there can be other signs of a deliberate intent besides the formality, or whatsoever it is, that the civil law requires in order to fix the rights of the parties. What is done without deliberate intent does not, as we also believe, attain to the force of an obligation, a fact which Theophrastus noted in his book on Laws. As to that which is done deliberately, but without an intent to grant a corresponding right to another, we declare that a right of enforcement is not thereby naturally given to any one, although we admit that there arises not only a question of honor, but also a kind of moral necessity.

The passage taken from Cicero we shall treat below, when we speak of the explanation of agreements; but let us now see what is required to constitute a perfect promise.

V.     That for a perfect promise the possession of reason on the part of the promisor is requisite; herein the law of nature is distinguished from the civil statutes in regard to minors.
1.   The first requisite is the use of reason; consequently the promises of madmen, idiots, and children are null and void. A different opinion should be held in regard to minors. Although it is in fact believed that minors possess a rather weak judgement, as also women, nevertheless this is not a lasting condition, and in itself it is not sufficient to destroy the force of an action.

2.   Now the time when a boy begins to employ reason cannot be absolutely fixed, but must be assumed from his daily acts, or even from what commonly happens in any region. And so among the Jews a promise was valid which was made by a youth who had completed his thirteenth year, or by a girl who had completed her twelfth. Elsewhere, not only among the Romans but also among the Greeks, as Dio Chrysostom states in his seventy-fifth Oration, the civil laws with good reason declare certain promises of wards and minors void; and against certain other promises they provide the favor of restitution.

These, however, are the special effects of municipal law, and they therefore have nothing in common with the law of nature or the law of nations, except that it is natural that they should be observed in the places where they are in force. In consequence, if a foreigner makes an agreement with a citizen, he will be bound by the laws of the latter’s country, for the reason that a person who makes a contract in any place is under the law of that place as a temporary subject.

3.   The case will be clearly different if the agreement is made on the sea, or on a desert island, or by means of letters between those who are at a distance. For such agreements are governed by the law of nature alone, as are also the agreements of those who hold sovereign power, in so far as this affects their sovereign right. For in the promises which they make in their private capacity even those laws have effect which make the act void where this is to their own advantage, but not when the act is to their loss.

VI.     Whether a promise given under a misapprehension is by the law of nature binding, and to what extent.
1.   The treatment of agreements based on a misapprehension is perplexing enough. It is, in fact, customary to distinguish between errors which affect the substance of the matter and those which do not; to consider whether a contract was based on fraud or not, whether the person with whom the contract was made was a party to the fraud, and whether the act was one of strict justice or only of good faith. For in view of the diversity of these cases the writers declare some acts void and others binding, but in such a way that they may be annulled or changed at the choice of the one injured.

The majority of these distinctions come from the Roman law, not only the old civil law, but also the edicts and decisions of the praetors; and some of them are not entirely true or accurate.

2.   Now a method of ascertaining the truth according to nature is furnished to us by the fact that as regards the force and effect of laws nearly every one agrees that, if a law rests upon the presumption of a certain fact’ which does not actually obtain, then that law does not apply; for the whole foundation for the law is overthrown when the truth of the fact fails. The decision when a law has been based on such a presumption must be inferred from the substance, words, and circumstances of the law.

In like manner, then, we shall say that, if a promise has been based on a certain presumption of fact which does not so obtain, by the law of nature it has no force. For the promisor did not consent to the promise except under a certain condition which, in fact, did not exist. To this principle should be referred the question in the first book of Cicero’s On the Orator, concerning the man who, falsely believing that his son was dead, had named another as heir.

3.   If, however, the promisor was careless in investigating the matter, or in expressing his thought, and another has suffered loss therefrom, the promisor will be bound to make this loss good, not from the force of the promise, but by reason of the loss suffered through his fault, a subject which we shall treat below.

On the other hand, if there was an error present indeed, but the promise was not based thereon, the action will be valid, since true consent was not lacking. But in this case also, if the person to whom the promise is made has by fraud caused the error, according to that other principle of obligation he will have to make good whatever loss the promisor has suffered in consequence of the error. If the promise only in part was based on error, it will be valid as to the remainder.

VII.     That a promise made under the influence of fear is binding, but that the person who caused the fear is under obligation to secure the release of the promisor.
1.   No less involved is the discussion of that which is done under the influence of fear. For in this case also a distinction is ordinarily made between a fear that is very great, either in its own nature or with reference to the person fearing, and a fear that is slight; between a fear that is justly and one that is unjustly occasioned; again, whether the fear was caused by the one to whom the promise is made, or by another; and also a distinction is recognized between acts that are generous and those that are burdensome. In accordance with these distinctions some acts are said to be void, others revocable at the will of the promisor, and others entitling to entire restitution. In regard to all these cases there is a great variety of opinions.

2.   On the whole I accept the opinion of those who think that the person that makes a promise under the influence of fear is bound by it, if the municipal law, which can annul or diminish an obligation, is not taken into consideration. For in such a case there is a consent, not conditional, as we just now said in regard to the person in error, but absolute. As Aristotle, in fact, has rightly stated, the man who throws his property overboard because of the fear of shipwreck would wish to save it conditionally, if there was no danger of a shipwreck. But, considering the circumstances of the place and time, he is willing to lose his property absolutely.

At the same time, this, I think, is indubitably true, that if the person to whom the promise is made has inspired a fear, not just but unjust, even though slight, and the promise has resulted therefrom, he is bound to release the promisor, if the latter so wishes, not because the promise was without force, but on account of the damage wrongfully caused. The exception to this, which is allowed by the law of nations, I shall explain below in its proper connection.

3.   The rule, that some acts are made void on account of fear inspired by a different person’ from the one with whom the agreement is made, belongs to municipal law, which often makes void or revocable acts that were freely performed, but performed by a person possessed of weak judgement. Here I wish to assume also the repetition of what I said above about the force and effect of municipal law. What effect an oath has in strengthening promises we shall discuss below.

VIII.     That, in order that a promise may be valid, that which is promised ought to be within the power of the promisor.
1.   In order that a promise may be valid, the subject of it ought to be either actually or potentially under the control of the promisor.

In the first place, then, promises to perform an act which is in itself illegal are not valid; for no one has, and no one can have, a right to do anything that is unlawful. A promise, as I said above, takes its force from the power of the promisor, and does not extend beyond. When Agesilaus was asked about a promise, he replied ‘If it is just, well and good; but if not, I only said it, I did not make a promise.’

2.   Again, if the thing is not at present within the power of the promisor, but may be at some future time, the validity of the promise will be in suspense; under such circumstances the promise ought to be thought of as made on the condition that the thing should come into the power of the promisor. But if the condition under which the thing can come into the power of the promisor implies his power to obtain it, the promisor will be bound to do whatever is morally right, in order to fulfill the promise.

3.   In this class also ordinarily the civil law makes many promises void which would naturally be binding. Such is the promise of future marriage by a man or woman who is now married; such also are nova few promises made by minors, or by children subject to parental control.

IX.   Whether by the law of nature a promise to do an illegal act is binding; explanation, with a distinction.
At this point the question is customarily raised, whether the promise to perform an act which by nature is morally wrong is by the law of nature valid; as if, for instance, something should be promised to a man for committing a murder.

In such a case it is clear that the promise itself is criminal; for it is made to this end, that another may be induced to commit a crime. However, not everything which is done wrongfully loses the effect of a right, as is apparent in the case of an extravagant gift. But there is this difference, that when such a gift has been made the wrongful act comes to an end; for the property is left in the hands of the recipient, without further harm. In promises made for a wrongful cause, however, the fault continues as long as the crime has not been committed; for during so long a time the fulfillment of the promise as an allurement to crime carries a moral blemish within itself, and this comes to an end only after the crime has been committed. Hence it follows that up to this time the effectiveness of such a promise is in suspense, just as we said above in regard to the promising of a thing which is not in our power. But when the crime has been committed the force of the obligation, which from the beginning was not intrinsically lacking but was restrained by the accompanying wrong, is revealed. An example of this can be adduced in the case of Judah, the son of Jacob, who paid the promised hire to Tamar, whom he thought a courtesan, as if it were due.’

Now if the injustice of the one to whom the promise was given has furnished the occasion for it, or if there is unfairness in the contract, the proper remedy is a different question, which we shall treat presently.

X.   What should be thought of a promise made to obtain a thing which was already due before the promise.
If we look to the law of nature, what is promised for a cause already due is not on that account the less obligatory, in the light of the principles which we stated above in regard to the accepting of another’s property. For a promise, even if made without a cause, by the law of nature would be binding. But in this case also loss through extortion, and unfairness in the contract, will have to be made good according to the rules which are to be laid down later.

XI.     The method of making a firm and binding promise in person.
As regards the mode of making a promise, that also, as we said about the transfer of ownership, requires an external act, that is, an adequate indication of intent, for which sometimes a nod may suffice, but more often the spoken word or writing is employed.

XII.     The method of making a binding promise through the agency of others; also concerning ambassadors who exceed their powers.
But we may be obligated also by another, if there is no doubt concerning the intent with which we chose him as our agent,’ whether specifically for the business in hand, or under a general appointment. In the case of a general authorization it can happen that our agent may obligate us by acting contrary to our desires as expressed to him alone. In such a case two acts of will must be distinguished, one by which we bind ourselves to ratify whatever our agent does in business of such a nature, and the other by which we bind him not to act except according to our directions, which are known to him but not to others.

This distinction is to be noted with respect to those promises which are made on behalf of kings by ambassadors, by virtue of the power contained in their credentials, but which exceed their secret instructions.’

XIII.     To what extent obligations incurred through the agency of ship-captains and through business agents arise from the law of nature; wherein also an error of the Roman law is pointed out.
From this we can understand also that actions associated with the transactions of ship-captains and business agents, which, strictly speaking, are elements of actions rather than actions, come within the purview of the law of nature.

In this connection it should be added that by the Roman law the provision was wrongfully introduced that shipowners should individually be wholly responsible for the acts of the captain. This provision, in fact, is neither in accord with natural justice, which considers it sufficient if individuals are responsible according to their proportionate shares, nor is it advantageous for the public good. Men are deterred from engaging in commerce if they are afraid that they will be held accountable for the acts of the captain as if to any limit.

For such reasons among the Dutch, whose commerce has greatly flourished for a long time, that law of the Romans was not formerly, and is not now, observed. On the contrary the principle has been established that, in respect to responsibility for the acts of the captain, all the owners together are liable for no more than the value of the ship and the cargo.

XIV.     That the acceptance of a promise is necessary to make it binding.
In order that a promise may transfer a right, the acceptance of it is no less necessary than when a transfer of ownership’ is made; yet in this case also it is understood that a preceding request continues, and has the force of an acceptance. And no obstacle is presented to this view by the rule of the civil law concerning promises made to the state. Nevertheless this consideration has led some to judge that the act of promising is alone sufficient. However, the Roman law does not say that the promise has full binding force before the acceptance, but forbids the revocation of the promise, in order that the acceptance may be possible at any time.

This effect does not follow from the law of nature but merely from the civil law. Not unlike it is the effect of the custom which the law of nations has introduced on behalf of infants and idiots. For in the interest of such persons, just as the law supplies the intent to possess the things which are sought, so it supplies also the intent to accept them.

XV.     Whether an acceptance ought to be made known to the promisor; explanation, with a distinction.
This question is also commonly raised, whether it is sufficient that the acceptance be signified, or whether, in fact, the acceptance ought also to be made known to the promisor before the promise attains its full effect.

It is certain that a promise can be made in both ways, either thus: ‘I desire that this be valid, if it be accepted’; or thus: ‘I desire that this shall be valid if I shall have understood that it has been accepted.’ In promises which deal with mutual obligations the latter meaning is assumed, but in merely generous promises it is better that the former meaning should be believed to be present, unless something else should appear.

XVI.     That a promise can be revoked if the one to whom it was made died before accepting it.
Hence it follows that before acceptance a promise can be revoked without injustice, since the right has not yet been transferred; and such a revocation will even be without inconsistency if in truth the promise was made with the intent that it should begin to be binding only after acceptance.

Furthermore a promise can be revoked if the person to whom it was made dies before accepting it, for the reason that the acceptance seems to have been submitted to his decision and not to that of his heirs. It is, in fact, one thing to wish to give to a man a right which will pass to his heirs, and another to wish to give directly to the heirs; I for it makes a great difference upon whom the favor’ is conferred. This is in accord with the response of Neratius, ‘that it did not seem to him that the prince would have granted to a dead man what he had granted to the person who he thought was living.’

XVII.     Whether a promise is revoked on the death of an intermediary; explanation, with distinctions.
1.   A promise can be revoked also on the death of the person who has been chosen to convey orally the promisor’s intent, for the reason that the obligation had been based on his words. The situation is different in the case of a messenger who has not an instrumental part in the obligation, but is merely the bearer of the obligatory instrument. Similarly letters, which indicate consent, can be carried by any one.

Further, we must distinguish between the servant who has been chosen to report the promise and the agent authorized to make the promise himself. In the former case the revocation will be fully binding, even if it be not known to the servant; but in the second case a revocation will not be valid, because the .right of promising was dependent on the will of the representative himself, and this will was without fault in promising, because lacking knowledge of the revocation. So, again, in the former case a donation can be accepted after the death of the giver, as being completed on the one side, though it had been subject to revocation; and this is easier to perceive in the case of embassies. In the second case the gift cannot be accepted, because it was not made but merely ordered to be made.

2.   In case of doubt the conclusion is that it was the intent of the person who directed the making of the promise that it be fulfilled, unless some great change has occurred, such as. the death of that person. Nevertheless there may be presumptions which suggest a different decision, and which ought to be easily admitted, so that a gift which was to be given for a worthy cause may be made. In a similar manner the question formerly discussed, as to whether a right of action on the order to make a promise exists against the heir, can be settled; on this matter the author of the Ad Herennium reports that the praetor Marcus Drusus gave a decision on one side, and Sextus Julius on the other.

XVIII.     Whether a promise is revocable after acceptance by a proxy; explanation, with distinctions.
1.   Disputes are wont to arise also in regard to an acceptance given by proxy. In such cases we must distinguish between a promise made to me about giving something to another and a promise conveyed in the name of the person to whom the thing is to be given. If the promise has been made to me without regard to the question whether I am personally interested – a distinction which was introduced by the Roman law – it seems that in accepting by the law of nature I am given the right of effecting the transfer of the right to the other party, if he also accepts, and in such a way that in the meantime the promise cannot be revoked by the promisor. On the other hand I who have received the promise may remit it. For this opinion is not inconsistent with the law of nature, and it is particularly in harmony with the wording of such a promise. And to me it is not a matter of indifference whether another person receives a favor through me.

2.   Now if the promise has been conveyed in the name of the person to whom the thing is to be given the distinction must be made whether the one who accepts it has a special authorization to accept it, or an authorization so general that such an acceptance ought to be considered as included therein, or whether he has no authorization whatever. Where such an authorization has preceded I do not think that we should insist on the further inquiry whether the person is his own master or not, as the Roman law provides; we should rather consider that by such an acceptance the promise. is fully completed, because consent can be transmitted and indicated even by the agency of a servant. I am in fact considered to wish what I have entrusted to the will of another, if he also wishes it.

When, however, there is no authorization, if another to whom the promise was not made should with the permission of the promisor accept it, the result will be that the promisor is not permitted to revoke his promise until the person whom it concerns has accepted or refused. Yet in the meantime the one who has accepted cannot remit the promise, for in this case he was not employed to accept a right, but merely to bind the good faith of the promisor in fulfilling the favor. And yet the situation is such that, if the promisor should revoke his promise, he would be acting contrary to good faith and not against the individual right of any one.

XIX.   At what time a burdensome condition can be added to a promise.
From what has been said we can understand also what ought to be thought about the addition of a burdensome condition to a promise. This can, in fact, take place so long as the promise has not been completed by acceptance, nor made irrevocable by giving a pledge. Moreover a burdensome condition to the advantage of a third party can be revoked so long as it has not been accepted by that party.

There are, nevertheless, some who think differently in regard to this matter, as well as on other questions. But the natural equity is so easily apparent to one who examines the matter rightly that it does not need many proofs.

XX. How an invalid promise can be made binding.
The question is also commonly discussed, how a promise, which was based on a misunderstanding, can be made valid if, after the error has been found out, the promisor wishes to keep his promise. The same question can be raised also in regard to promises which the civil law makes void because of fear, or for any other cause, if the cause has afterwards ceased to have effect.

To confirm such promises some require merely a mental act which, joined with the previous external act, they consider sufficient to produce a binding obligation. Others, who are dissatisfied with this requirement, because an external act cannot be the sign of a mental resolve which comes later, require a new verbal promise and acceptance.

The truth rather lies between these two views. An external act is indeed required, but it is not necessarily expressed in words; for the retention of the thing promised by the person to whom the promise was made, and the abandonment of it on the part of the promisor, or some similar act, may suffice to indicate consent.

XXI.     That promises without cause are not void by the law of nature.
In order that the civil law may not be confused with the law of nature, this statement also must not be omitted, that promises, which have no cause expressed, are not by the law of nature void, any more than material gifts.

XXII.     To what degree a person who has promised an act of another is bound by the law of nature.
A person who has promised the act of another is not held accountable for the material interest involved, provided he has not omitted to do what he could on his own part to secure the action, unless the words of the promise or the nature of the business add a more strict obligation. ‘As if he had fulfilled his pledge,’ says Livy, ‘because he had not been to blame for its non-performance.’