André Lapidus

Keywords: Grotius, Price, Exchange, Contract JEL Classification: B11, B31, K12, Z12

This paper explores the way Grotius, in the chapter on contracts of the book from De Jure Belli ac Pacis (1625) where the causes of the birth of war are discussed, elaborated an original understanding of exchange and price which occupies an interesting position between the scholastic analysis where price was compared to a norm of just price and the later articulation, in classical economic thought, betweentypicallynatural prices and market prices. With Grotius, the issue was no longer the morality or sinfulness of the transaction, and not yet its exclusive economic concern, but its lawfulness. Drawing on Roman law, his starting point was a critical construction of a typology of acts from which he derived a normative analysis of exchange, which combined three types of equality, relating to information, to the absence of coercion and, finally, to the thing exchanged itself. The realisation of this equality in exchange first makes it possible to identify the legally acceptable price associated with it, a common price understood in an equivalent way by a socially recognised need that measures it or by the labour and expenses of the merchants. This legal acceptance then extends to transaction prices that may deviate from the common price, either because of variations in the tastes of the parties and in the scarcity of the good, or because, in the absence of a common judge, under the law of nations, of the agreement of the seller and buyer through a bargaining process made it acceptable.

Introduction

On 30 March 1763, Adam Smith explained his students that " [t]here are properly speaking two sorts of price on commodities, which tho they appear unconnected are nevertheless very closely connected" (Lectures on Jurisprudence (1762-3), vi.58; see also vi.67, vi.76, and (1766), 224, 229). What was to follow is well-known: Smith's distinction between natural and market prices opened the path to a way of understanding price which ran throughout the whole classical period. Through its different variants, this amounted to understanding price not as an isolated, single category, but as a hierarchical structure of two or more fields of evaluation. Stated differently, what Smith initiated by * Phare, University Paris 1 Panthéon-Sorbonne, France (andre.lapidus@univ-paris1.fr).

addressing the two kinds of prices in this way was a hermeneutic: understanding the price did not mean understanding what determines directly, say, the current market price, but understanding what determines first, the natural price and then, what determines the possible gap between the natural and the market priceand, consequently, what determines the possible deviation of the second from the first. But what about that which came before Smith's hermeneutic, for which each kind of price had a direct economic meaning?

If Smith considers the distinction between "two sorts of prices" as commonsense, it is because such distinction had already existed for a very long period during which economic issues related to price were embedded into normative concerns. It could be argued that the Scholastic theory of price, such as in Thomas Aquinas's Summa Theologiae (IIa-IIae, q. 77) at the end of the 13th century, was an example of such embedment into normative concernshere, religious and moral [START_REF] Lapidus | Le Prêt à Intérêt Face à la Religion et au Droit. Imbrication et Séparation aux Premiers Moments d'une Histoire Longue[END_REF]: the possible gap between an effective price and the just price in a transaction ("just" in that it complies with the moral requirements of commutative justice) was interpreted in terms of information and of the moral characteristics of the buyer and the seller (see [START_REF] Lapidus | Norm, Virtue and Information: Individual Behaviour and the Just Price in Thomas Aquinas' Summa Theologica[END_REF]Chaplygina and Lapidus 2016, pp. 25-26;Januard 2022b). In a way, the conditions for the acceptability of a price in a transaction, advocated by the theologians which followed Thomas, can be seen as sophisticated devices whose purpose was to enlighten the priest about the private information constituted by the morality of the seller and the buyer.

But in this long journey from the scholastic authors to Adam Smith, something changed with Hugo Grotius ' De Jure Belli ac Pacis (1625) 1 , and this despite a longrecognised affiliation with scholasticism (see Knight 1925, pp. 210-221;Saint Leger 1962, pp. 45-57). What has been called the "impious hypothesis" [START_REF] Crowe | The "Impious Hypothesis": A Paradox in Hugo Grotius?[END_REF], that is, the idea that the laws of nature remain true even though one concedes "that there is no 1 After Schumpeter's lack of interest (Schumpeter 1954, p. 112), Grotius' work has received little attention from economists. Among the few exceptions are H. [START_REF] Sewall | The Theory of Value before Adam Smith[END_REF] on his conception of price within the long evolution that led to Adam Smith; I. Hont (1990) on his influence on the birth of Scottish political economy; J. [START_REF] Salter | Sympathy with the Poor: Theories of Punishment in Hugo Grotius and Adam Smith[END_REF] on poverty; P. [START_REF] Borschberg | Hugo Grotius, the Portuguese, and Free Trade in the East Indies[END_REF]C. Suprinyak (2022) on his doctrinal position on free trade; A. [START_REF] Lapidus | Le Détour de Valeur[END_REF][START_REF] Lapidus | Le Prêt à Intérêt Face à la Religion et au Droit. Imbrication et Séparation aux Premiers Moments d'une Histoire Longue[END_REF][START_REF] Lapidus | Hugo Grotius on Usury: Acknowledging the End of the Scholastic Argument[END_REF] on the relation with legal concerns, money loans and prices.

God, or that human affairs are of no concern to Him" (De Jure,Prol.,11) 2 , had the result that the shift of normative concerns to legal content could give up all religious considerations. Thus, the elements of economic reasoning, particularly those related to price, could be established through a critique of legal categories derived from Roman law, at the end of which it was now a matter of enlightening the judge and no longer the priest.

Grotius' starting point was a critical construction of a typology of acts from which he derived a normative analysis of exchange. The latter uses a conception of justice obviously inherited from Aristotle, but which combined three types of equality, relating to information, to the absence of coercion and, finally, to the thing exchanged itself (section 2). The realisation of this equality in exchange first makes it possible to identify the legally acceptable price associated with it, a common price understood in an equivalent way by a socially recognised need that measures it or by the labour and expenses of the merchants. This legal acceptance then extends to transaction prices that may deviate from the common price, either because of variations in the tastes of the parties and in the scarcity of the good, or because, in the absence of a common judge, the agreement of the seller and buyer through a bargaining process made it acceptable (section 3).

Acts, exchange, and equality

Grotius dealt with economic issues mainly in Book II of De Jure Belli ac Pacis, when discussing the causes of war, and thus of ownership, its acquisition and transfer. And it is as a result from the legal examination of obligations deriving from ownership that he introduced the Chapter 12 on contracts, which gathers most of the material on exchange, price, money and lending.

From a typology of acts to exchange

The perspective from which Grotius approaches economic matters is that of a typology of "acts" (see Lapidus 2021, pp. 104-106 and2022), either "simple" or "mixed" (De Jure,II,12.1). Simple acts are so called because, unlike mixed acts, they produce a single advantage for each party to the contract, from a legal point of view. Mixed acts, therefore, are viewed as combinations of simple acts. The latter are divided between "permutatorial acts" (permutatorii) as opposed to "beneficial acts" (benefici) (De Jure,II,12.2). Most of what we identify as exchange situations or organisations fall under the header of permutatorial acts3 , which are themselves divided, as already explained Roman jurisconsults, into acts that "separate the parties" (dirimunt partes) and acts that "produce a community" (communionem adferunt) (De Jure,II,12.3.1). A sale, for instance, belongs to permutatorial acts which separate the parties (De Jure,II,12.3), whereas a partnership (societas) is an example of acts that produce a community (De Jure,II,12.4).

It remains that most exchange situations are treated through the case of permutatorial acts that separate the parties, for which Grotius proposed a combinatorics (De Jure,II,12.3.3), derived from the Digesta. This combinatorics comes after a discussion on the reciprocal obligations of two free men, each of them having had a natural son with the other's slave, and who want to have their child emancipated. Paul generalized the issue:

Either I give to you so that you give to me, or I give to you so that you do something for me, or I do something for you so that you give to me, or I do for you so that you do for me (Digesta,19.5.5).

Each modality, giving or doing, for each party is given a content by Grotius, so that he could systematically illustrate various situations of exchange: • doing / doing (facti cum facto permutatio) "innumerable kinds" (De Jure,II,12.3.5) military service / protection (within the feudal contract; De Jure, II, 12.5)

• doing / giving (facio ut des ;De Jure,II,12.3.5 The outstanding characteristic of this combinatorics is less in the variety of examples which it provides explicitly than in the absence of any illustration for several items, like the empty cells of the Mendeleev table in its original form, which shows that it covers potentially the whole range of exchange situations involved in simple permutatorial acts that separate the parties. Moving to mixed acts allow introducing exchange situations in which the contract offers one party more than one advantage. This is the case, for instance, with the foenus nauticum, the sea loan. The foenus nauticum has long been considered a possible substitute for a usurious money loan (Lapidus 1991, pp. 32-34).

Grotius simplified this discussion by considering it as an elementary combination, within a mixed act, between two simple acts: a free, therefore non-usurious, loan contract, the mutuum, in which money is given for the subsequent return of the same amount of money, and an insurance in which money is given by the borrower in return for the compensation of a peril if it occurs: So, the sea loan is a mixture between a contract of mutuum and an insurance [foenus quoque nauticum mixtum quid est ex contractu mutui, et periculi aversi]. (De Jure,II,12.5).

Interestingly, it is only after having constructed a typology of acts, simple and mixed, and in relation to them, that Grotius introduced the contracts, which are however the subject of chapter 12. He defined them (De Jure,II,12.7) as a subset of the set of acts, from which are withdrawn those beneficial acts which he called "mere beneficial" (mere beneficos), in which we can recognize what will be later identified as a gift without a counter-gift4 . In the tradition of the moral philosophy inherited from Thomas Aquinas, this would amount to saying that contracts are those acts which are not exclusively governed by the virtue of charity.

In this way, contracts might be identified with exchange, understood in a broad sense since they also include i) mixed acts in which a mere beneficial act is combined with a permutatorial act; ii) beneficial acts with mutual obligations, like gifts and counter-gifts, whose belonging to exchange is not consensual; iii) permutatorial acts which produce a community, which include various types of partnership. By contrast, exchange in a narrow sense, from which an explicit price emerges, is a subset of contracts which corresponds to permutatorial acts which separate the parties for simple acts, or to a combination of such simple acts for mixed acts. An immediate consequence is that what Grotius explained in the following of his chapter also applied to exchange, broadly or narrowly understood.

Equality of what?

On first view, when Grotius wrote that "[i]n contracts, nature commands equality" (De Jure,II,12.8), this seems to echo Thomas Aquinas's position according to which in commutative justice, "it is necessary to establish an equality from thing to thing [opportet adaequare rem rei]" (Summa Theologiae, IIa-IIae, q. 61, a. 2, resp.). Yet, Grotius' target for equality is wider than the one borrowed by Thomas to the Aristotelian concept of reciprocal justice: where Thomas first refers to an equality of thing to thing in a just exchange, and then specifies the conditions under which it can be achieved, depending on the morality of the parties, of their information, even in the case of an accidental exchange [START_REF] Lapidus | Norm, Virtue and Information: Individual Behaviour and the Just Price in Thomas Aquinas' Summa Theologica[END_REF]), Grotius presents equality as governing not only the things exchanged, but also the circumstances of this exchange:

This equality is required both in the acts and in that which is in question with these acts; and in respect to the acts, it covers the preceding as well as the principal acts (De Jure,II,12.8).

What follows immediately Grotius' point about the extent of equality is a systematic account of the way it is involved in acts and matter of acts. From an economic point of view, this amounts to an account of how equality is involved in prescriptive statements relative to information and coercive power.

Equality as regards information can be interpreted as an equal access to relevant information about the thing exchanged. This is presented as a natural requirement of the contract:

[T]he person who is making a contract with any one ought to point out to him the defects of the thing in question which are known to himself: this is not only prevailingly established by the civil laws, but is also consistent with the nature of the act. For between the contracting parties, there is a closer association than what is common to mankind. […] [T]he nature of a contract which was devised for the sake of mutual advantage requires something closer (De Jure, II, 12.9.1).

It is emphasised that the information to be disclosed is only that which is relevant to the expectations of the buyer and seller. Grotius gave several examples, borrowed from Roman law, where irrelevant information does not need to be mentioned (De Jure, II, 12.9.1); and this was extended to the case of an already known information, which does not need to be repeated (De Jure, II, 12.9.3). However, he is careful to give specific treatment to the classic case discussed by Thomas Aquinas (Summa Theologiae, IIa-IIae, q. 77, a. 3, obj. 4 and ad 4), where "many ships are in route, bringing grain". His conclusion is by the way coherent with that of his predecessor:

The giving of such information is, in fact, a part of one's duty, and praiseworthy, so that often it cannot be omitted without violating the rule of charity [caritatis regula]. Yet such omission is not unjust, that is, it is not repugnant to the right of the one with whom the trade is made (De Jure, II, 12.9.2).

Reference to charity shows that revealing the information, which would be praiseworthy, transforms the act from permutatorial into mere beneficial, so that it falls outside the scope of exchange. On the other hand, concealing it would surely be less praiseworthy, but since the contract deals with a present sale of grains, the information about what will arrive tomorrow is supposed to be irrelevant to the present transaction. Consequently, if a seller is allowed to conceal such information, it is not because he has some license to cheat, but because for him as for the buyer, intertemporal separability applies. Note, however, that Grotius' position in the case of a spot transaction seems to be governed by legal, contract-related concerns, different from those which prevail in the case of forward operations. A similar position was expressed about some kinds of private monopolies (De Jure,II,12.16). In other places he had made clear that he was aware of the differences between the present value of a present good and that of an identical but future goodan example of intertemporal non-separability. His argument for allowing interest loans is worth recalling: "the right of repaying money or wine borrowed only after a certain time is something capable of being evaluated: for he pays less who pays late" (De Jure,II,12.20.2).

The second domain of equality is the reciprocal absence of coercion. This does not mean that all fear has to be withdrawn from the contract. What Grotius called "extrinsic" fearthat is, extrinsic to the contractmight be at the origin of the willingness to contract, and it has not to be removed. On the contrary, when the fear is "unjustly inspired for the sake of making the contract", it should be removed (De Jure,II,12.10). It is obvious that this requirement, in the framework of a bilateral exchange, results in the solution not depending on the respective bargaining power of the buyer and seller. Thus, the equality relating to information and the equality relating to the absence of coercion converge in their effects to set the bounds of a negotiation space within which the last equalitythat relating to the thing being exchangedwill be achieved. This third and last equality, related to the thing exchanged, is introduced indirectly by Grotius in two steps. First, by opposing exchange to beneficial acts: Whatever, in fact, the parties promise or give, they should be believed to promise or give as on an equality with that which is about to be received, and due by reason of that equality (De Jure,II,12.11.1).

Then, after recalling the two previous equalities, and imagining the case where such equality, related to the thing itself which is the matter of the transaction, is not respected:

There remains equality in the matter in question [aequalitas in eo de quo agitur; equality related to the thing], consisting in this, that although nothing has been concealed which ought to have been said [equality related to information], and no more has been exacted than what was considered due [equality related to non-coercion], nevertheless if an inequality has been detected in the thing [si in re tamen deprehendatur inaequalitas], although without the fault of either party […], this inequality should be repaired, and something should be taken from the one who has more and given to the one who has less; for in the contract it was proposed, or ought to have been proposed, on both sides, that each should have the same amount (De Jure,II,12.12.1).

This makes clear the effectiveness of Grotius' construction. It aimed to distinguish three possible ways of violating the laws of nature 5 on the course of an exchange. These are three ways of introducing inequality: i. inequality related to information; ii. inequality related to non-coercion; iii. inequality related to the things exchanged. Each of these requires its own legal treatment, but they should be examined in this order, since an inequality related to the things might be meaningless if it is preceded, for instance, by an inequality related to information.

Common price and transaction price

The exchange system devised by Grotius makes it possible to eliminate, in successive stages, the various sources of inequality until an equal exchange ratio is achieved. Yet we only know that such equal exchange ratio, which seems to play the same role as the just price in scholastic economic thought, should exist. We do not know yet how it is determined.

Common price: from need to labour and expenses

The answer is to be found in a discussion about the way a price is measured. In a few paragraphs, drawing on Aristotle and the commentaries of the Roman jurisconsults, Grotius brought together the three ways the issue was dealt with throughout the Middle Ages 6need (indigentia), labour and expenses of the merchants (laborum et expansarum, quas mercatores faciunt), and common estimation (quanti omnibus valeret) and proposed an ingenious way of relating them (De Jure, II, 12.14. 1 and 2).

The starting point, explicitly relying on Aristotle, is a natural value given by need:

The most natural measure of what any thing is worth is need, as Aristotle rightly shows (De Jure, II, 12.14.1). 5 Grotius developed a conception of what was to be identified later as modern natural law (see [START_REF] Haakonssen | Natural Law and Moral Philosophy: From Grotius to the Scottish Enlightenment[END_REF], in which "natural law is so immutable that it cannot be changed by God himself" (De Jure, I, 1.10.5), so that its source should be searched in the consistency of our actions with our humanity, as rational and as social beings (see also [START_REF] Lapidus | Hugo Grotius on Usury: Acknowledging the End of the Scholastic Argument[END_REF]. 6 Both needs and labour and expenses were mentioned, for instance, by Thomas Aquinas in his commentaries on Aristotle's Ethics (Ethicorum, lib. V, lec. 9). See Januard 2022a, p. 754.

The rest of the sub-section makes it clear that, as with Grotius' distant scholastic predecessors, the need (indigentia) in question was not about the fancy of a transient desire, but rather the permanence of socially recognized wants (see Lapidus 1986, pp. 20-21;Langholm 1987, pp. 122-125 for a lexical discussion; Chaplygina and Lapidus 2016, pp. 23-24) 7 . But Grotius held that in thinking we were measuring need, we could be mistaken. For, he wrote, "Nor is this the only measure". And he gave several indications on what might be measured, instead of indigentia: the "will of men" (hominum voluntas), which can make us long for something beyond what is necessary; or the "desire" (cupiditas), the measure of which, he said, quoting Cicero, "is the estimation of things".

It is remarkable that these examples (De Jure, II, 12.14.1) revolve around the same idea: a subjective appraisal of things can lead to a measurement of their price, on the occasion of a real or imagined transaction, different from that determined by a socially recognized need, independent of any subjective content. This measure which would depart from the need is further reinforced by the symmetrical consideration of the available quantities of the traded good: "the most necessary things [according to indigentia] are worth less because of their abundance [propter copiam]" (De Jure, II, 12.14.1).

The result is that what he called the "most natural measure" of a price, its socially recognized need, might differ from transaction prices, which are driven by subjective desires and the scarcity of the thing exchanged. But the difficulty to identify this most natural measure led Grotius to approach it in another way. This was performed in the continuation of his previous observations. Facing the disparities in individual assessments, Grotius dismissed them since such assessments, treated like reservation prices, did not mean that a thing could be sold or bought for this price, but only for a commonly observed price, common therefore to most transactions. Quoting Seneca (De Beneficiis,VI,15), he concluded with him:

7 Earlier developments showed that the vocabulary used had already moved away from indigentia to designate something closer to subjective utility. Bernardino of Siena, for example, whose works are widely recognised as a milestone in the first half of the 15th century in a Franciscan trend that runs from Peter of John Olivi to Gerald Odonis and Antoninus of Florence, speaks of complacibilitas, which refers to the desirability that, together with the ability of a good to satisfy human need (virtuositas) and its scarcity (raritas), determines its price (see Lapidus 1986, pp. 41-42).

The price of each thing depends on its time. Though you have praised [those things] highly, they are not worth more than they can be sold for [cum bene ista lauderis, tanti sunt quanto pluris venire non possunt] (De Jure, II, 12.14.1).

And further:

Hence it happens that a thing is estimated as much as is commonly [communiter] offered or given for it. (Ibid.).

At this point, there is no special reason to believe that the common price is not like other transaction prices (such was, for instance, Sewall's interpretation (1901, p. 38) of the common price as a current price), possibly different from the assessment given by need.

But Grotius went on, now quoting the jurisconsult Paul, by suggesting that this price is also "common" in another sensethat of a shared valuation:

The prices of things do not arise from the feeling or utility of individuals [ex affectu nec utilitate singulorum], but by common estimation; that is, as he [Paul] explains elsewhere, how much it would be worth to all (Ibid.).

Grotius here reversed the path he had taken at the beginning of the sub-section. He moved from individual subjective assessments to a shared assessment. Now, he had already observed that need was common "in the exchange of things among Barbarians". It is therefore easy to draw from this that the common price, in the sense of a shared assessment, is equivalent to the "most natural measure" of price, the need.

The following step was to move away from a representation in terms of a common price understood as a need, facing transaction prices depending on subjective evaluations, in favour of an alternative representation in terms of cost content which, here again, recalls the scholastic approach to the just price:

And in that common price, account is usually taken of the labour and expenses [laborum et expansarum] which the merchants incur; and it is also usually changed suddenly by the abundance and scarcity [copia et inopia] of buyers, of money, and of commodities (De Jure,II,12.14.2).

It is thus a construction modelled on the one in which need (indigentia) is the pivotal value that Grotius achieves, by substituting a production cost (labores et expansae) which, again, is intended to represent the common price. But where transaction prices could differ from the common price, understood as a need, because of subjective desires and the scarcity of the good, it is this same common price which, when understood as a cost of production, can be modified because of the scarcity of the commodity, of the partners in the exchange and of the money. Interestingly, this is a way of claiming that the need for a good, as represented by its common price, may change because, for example, it becomes scarcer. The need for water thus increases because it is less abundant and, in Grotius' representation, this is not because of our whims, but because everyone can recognise the lack of it.

Deviations from the common price

However, while the common price could vary, Grotius pointed out the reasons why a transaction price might nevertheless deviate from it. And he was careful to note that these deviations, which allowed a thing to be bought and sold for more or less than the common price, could be legal. Such legal prices of transaction, different from the common price, arise in response to "accidents involving estimable things" [rei accidentia aestimabilia] 8 . He gave successively several examples which have in common the compensation of a loss or a decline in profits (including because of an anticipated or delayed payment), or he imagined special feelings for a thing, or in a less familiar way, when some things "are bought or sold to oblige a person, being otherwise not to be bought or sold" (De Jure, II, 12.14.2). Some of these examples may seem odd to the contemporary reader, and one could discuss at length on what basis such of them would be considered legal, despite its deviation from the common price. But if we bear in mind that the approach adopted is that of a lawyer who intends to provide the judge with the means to assess the lawfulness of a transaction, the method followed becomes more transparent. After providing the magistrate with the means to determine a common price in accordance with natural law from a common estimate or from the labour and expenses of the merchants and giving the reasons for its variations, he specifies the conditions under which the transaction price may deviate from the common price, without this leading to its illegality. This legality of a transaction price distinct from the common price can, however, be understood in two ways: either, as in the cases just discussed, because it can be approved on account of the particular circumstances facing the buyer and seller; or because the law of nations (the jus gentium) itself cannot, or does not oppose it.

The latter case is addressed by Grotius in the last section of his chapter on contracts, where he mitigates the previous natural law considerations ("And indeed what we have said up to now is in accordance with the law of nature itself"; De Jure, II, 12.25) by approaching the same issues from the perspective of the law of nations 9 . It is from this point of view that he considered certain inequalities in exchange, however rejected by the natural law, as acceptable:

Nor does it appear that anything changed by the instituted law of nations; with one exception, that if an inequality of things be agreed upon, this, where neither lying intervened, nor reticence of what ought to have been said, is regarded as equality in external actions 10 . And thus, […] among those who are connected only by the law of nations, there is no demand or compulsion allowed on that account (De Jure,II,12.26.1). This means that, for example, if the seller has greater bargaining power, which contradicts equality with regard to the absence of coercion, so that the exchange would be unjust according to natural law, the existence of an agreement would make the resulting transaction price legal according to the law of nations. It is from this perspective that Grotius approached the position asserted by Pomponius in the Digesta (4.4.16.4), here again quoted extensively since the Middle Ages, that "in the price of selling and buying, it is naturally allowed to circumvent one another [naturaliter licere se mutuo circumvenire]" (De Jure,II,12.26.1). He discussed the word "naturally", arguing that it had to be understood in a looser sense, as "put for a received custom" (De Jure,II,12.26.2), which fits with the law of nations, not with this of nature. As for "allowed", he understood the word in a most restricted sense: 9 Recall that the law of nations (jus gentium), was the law which, comprising basic human protections, applied to all the inhabitants of Rome, including those who, not being Roman citizens, were not subject to civil law. It was an intermediate law, between natural and civil law, derived from customs and human reason. A typical example was this of slavery, then regarded as accepted by the law of nations, but not by natural law. 10 That is, equality in human interactions, as opposed to actions that would depend solely on one's own consciousness.

Where allowed is, not that it is right, but that it is so far permitted since there is no remedy against him who in such a case chooses to defend himself on the basis of the agreement (De Jure,II,12.26.1).

Bargaining under the law of nations

The possibility "to circumvent one another" reveals the kind of behaviour which is made possible by the law of nations. This was done with the help of a passage from the Codex of Justinian (Codex,4.44.8) which Grotius quoted the Codex almost literally: This is the substance of buying and selling (say the Emperors, meaning by the word "substance" a perpetual custom) that since the buyer desires to buy cheaper and the seller to sell more dearly, they reach this agreement; and with difficulty, after many disputes, little by little, while the seller lowers the sum which he had asked, and the buyer adds to his offer, they finally agree on a definite price (De Jure,II,12.26.3).

These lines, written in the first half of the 6th century, are striking for an economist today.

They precisely describe a bilateral exchange situation, which is typically known to have an indeterminate equilibriumthe indeterminacy being removed by the bargaining process. In the Codex like in the De Jure, this process was described quite accurately.

Yet, its interpretation is different in both cases.

In the Codex, the bargaining process followed on from a very concrete question concerning the possibility of rescission of the sale of a farm by the son of its owner because the latter considered that the price obtained was too low. The Codex claimed that "[t]he fact that you state that the land was sold for a little less than its value, is not alone sufficient to invalidate the sale" (Codex,4.44.8). And the reason provided was that the importance of the efforts accomplished made it unacceptable to question the agreement unless "less than half of the just price of the property at the time of the sale was given" (Ibid.). This example was discussed during the Middle Ages, in relation with the just price, as a case of what was to be called laesio enormis and progressively extended to the protection of any buyer or seller of any good. As a result, the local stability of the transaction was guaranteed by the extent of the efforts of both parties to reach an agreement through the bargaining process. From an economic point of view, this means that ex ante, the buyer and the seller accept such efforts because they know that neither of them (except in case of laesio enormis) will appeal to a court's judgment, so that these efforts will not have been carried out in vain.

Grotius approach was different. It was no longer a question of the sale of a farm, but of bilateral transactions within the legal framework of the law of nations, i.e. where the parties do not have a common judge. "[A]mong those who base their association on the law of nations alone", Grotius said, "no recourse or coercion [to a judge] on that account [inequality in the transaction] is allowed" (De Jure,II,12.26.1). It is in such context that he held that his "rules" (the legality of a bargaining process leading to inequality) are appropriate:

However, the advantage of introducing the rules which I have mentioned is manifest for the prevention of infinite disputes owing to the uncertain price of things between those who do not have a common judge [-disputes] which would have been unavoidable if men were allowed to withdraw from agreements on account of inequality (De Jure,II,12.26.3).

By contrast with the interpretation from the Codex, the de jure acceptance of a transaction price, even if unequal, on which the seller and the buyer have found an agreement at the end of a bargaining process ignoring the common price, where there is no common judge, is reinforced because the difficulties encountered during the bargaining process are less than those that would be experienced if any agreement could be challenged.

The point is not trivial. However, it must be qualified. The superiority of a bargaining process that allows for inequality and results in a transaction price binding for both parties, is only worth under the law of nations, when compared to a process whose outcome would be indefinitely challenged. But what if we compare this situation to that which would prevail according to the law of nature? Obviously, a common price which respects equality in exchange, or a transaction price which has good reasons to deviate from it in case of a bilateral transaction is better than the price obtained as the outcome of a bargaining process under the law of nations. Simply because what is just from the point of view of natural law is preferable to what is unjusteven if it is legal from the point of view of the law of nations. Grotius' conclusion was straightforward:

The writer of the life of Isidore, whom I mentioned a little before11 , says that buying at less or selling at more than what is just is an injustice, which is permitted indeed by law, but which in fact perverts what is just (De Jure,II,12.26.4).

Concluding remarks

Grotius economic analysis of exchange and price appeared as a by-product of a legal investigation in which the various types of contracts and their properties are explained on the basis of a typology of acts. Its purpose was to provide an hypothetical judge with the necessary elements to assess the validity of a transaction, according to either natural law or the law of nations. This requires obviously first to answer the question of the identification of a legally acceptable price. The operation was realized in three steps: i) a common price, determined through three equivalent channelsa socially recognised need, the work and expenses of merchants or a common estimationwhich guarantees equality in exchange; ii) transaction prices, which may deviate in an acceptable way from the common price, through changes in tastes or variations in scarcity; iii) transaction prices under jus gentium in bilateral exchanges, which are the result of a bargaining process, where equality is no more required and which cannot be the subject of litigation before a civil court.

Leaving aside the particular aspects of Grotius' construction, both from a legal and an economic point of view, which nevertheless still testify to its interest today, the fact remains that his approach illustrates the general issue faced by a normative perspective: the norm must be explained, and then the deviations from the norm. It is in this gap that economic reasoning is introduced. And this is what he bequeaths to posterity. To Samuel Pufendorf, first of all, whose work spread to Northern Europe and France, thanks to his translator Jean Barbeyrac, whom he shared with Grotius. Then to Gershom Carmichael, who disseminated his thought in Scotland, in what was to become the Glasgow School.

And then to his successor Frances Hutcheson, who was Adam Smith's professor and predecessor at the same university. Finally, to Smith himself, who could explain in the

•

  giving / giving (dari ut detur; De Jure, II, 12.3.4): thing / thing = barter (permutatio) thing / money = buying and selling (emptio ac venditio) money / money = change (cambium) use of a thing / thing [no example given] use of a thing / money = lease (locatio) use of a thing / use of a thing [no example given]

The edition of Hugo Grotius' De Jure Belli ac Pacis used in this text is that by J.B. Scott in 1913, which reproduces the 1646 edition, published just after Grotius' death. Where it seemed sufficiently faithful to the Latin original, the translations of Grotius' quotations follow the 1925 English translation by F.W. Kelsey. References are given according to the numbering of chapters, sections and sub-sections in Scott's and Kelsey's editions.

Some types of economic transactions, however, like deposit, commission or commodatum, are said to belong to beneficial acts(De Jure, II, 12.2).

"Mere beneficial acts" are the first subclass of the beneficial acts. The existence of a gift and a countergift corresponds, for Grotius, to the second subclass of beneficial acts which he called "beneficial acts with mutual obligations" (benefici actus cum obligatione mutua)(De Jure, II, 12.2).

Here again, this echoes what Thomas Aquinas said about exchange by accident (Summa Thologiae, IIa-IIae, q. 77, a. 1, resp. and ad 3), which might lead to a price different from the just price, but acceptable on moral grounds(Lapidus 1994, pp. 446-454).

Grotius explicitly mentioned Photios I, Ecumenical Patriarch of Constantinople in the second half of the 9th century. However, Photios did not write directly on the life of Isidore of Gaza: in his Bibliotheca, he included a review of the Life of Isidore by his contemporary Damascius, in the late 5th century.

Lectures and, even more so, in the Wealth of Nations, that when we speak of prices, we mean two different and yet interconnected things. Without, this time, the need to enlighten a magistrate.


André Lapidus

Acknowledging the End of the Scholastic Argument

Keywords: Grotius, Money loan, Usury, Interest, Contracts JEL Classification: B11, B31, E43, G00, K12, Z12

This paper explores the way the Scholastic argument against usury, which culminated in the 13th century with Thomas Aquinas's question on interest loans in the Summa Theologiae, found an end with Hugo Grotius's introduction of economic issues, in De Jure Belli ac Pacis (1625). Whereas Grotius inherited at least part of his predecessors' repugnance of interest lending, he found in his questioning of categories from Roman law the source of both a criticism of the main features of the Scholastic argument and an alternative analysis of interest loans in which the income received by the lender is explained and legitimate.

Introduction

The Scholastic argument against usury culminated in the 13th century with Thomas Aquinas's question on interest loans in the Summa Theologiae, when he provided foundations to the use of a loan contract from Roman law, the mutuum, which gave the borrower free ownership and use of a good for the duration of the loan. Such a position was both effective in that it made usury not only a moral fault but also a fault against reason, and soon disputed, since alternative representations rapidly emerged.

However, the definitive questioning of the Thomistic argument on usury was really achieved when it was opposed not only by an authority or a simple tolerance bias, but by a systematic elaboration which provided on the one hand an analytical criticism * PHARE, Université Paris 1 Panthéon-Sorbonne -Maison des Sciences Economiques -106-112, boulevard de l'Hôpital -75647 Paris Cedex 13 -France. E-mail : andre.lapidus@univ-paris1.fr. and, on the other hand, a reliable alternative construction. It could be argued that such elaboration is the result of a progressive movement 1 , combining two strands of evolution. The first one is an extension of the range of extrinsic titlesthat is, of the only reasons, external to the loan contract itself, for which a supplementary income might be given from the borrower to the lender. Peter of John Olivi, in the Tractatus de Contractibus (1293) or Alexander of Alexandria in his Tractatus de Usuris (1307), were examples of this extension (see, respectively, S. [START_REF] Piron | Présentation : Contextes Intellectuels et Sociaux du Traité des Contrats[END_REF][START_REF] Hamelin | Un Traité de Morale Économique au XIVe siècle -Le Tractatus de Usuris de Maître Alexandre d'Alexandrie[END_REF], whose final touch could be seen in Grotius's master in Rome, Leonard Lessius who introduced in 1605 a new extrinsic title, carentia pecuniaethe lack of money (see J. Noonan 1957, pp. 262-266;T. Van Houdt 1995;W. Decock 2007)in his De Justitia et Jure (Bk II,chap. 21). The second strand might be viewed as an ongoing debate rooted in a bull of Pope Nicholas III in 1279 (Decretales,Liber Sextus,V,tit.11,c.3, Exiit qui seminat) concerning the rule of the Friars Minors, which challenged the necessity of the mutuum as the necessary contract for money loans. The use which could be done of Exiit qui seminat in the usury debate appears in Gerald Odonis' Liber de Contractibus (1315-17)if not, some years before, in John Duns Scotus (see J. Noonan 1957, pp. 60-61;A. Lapidus 1991, p. 31;G. Ceccarelli and S. Piron 2009, n. 78, p. 186) in order to support the idea that in a money loan, the transfer of its use might be separated from its ownership.

We can consider that these two currents converge in Hugo Grotius's work, De Jure Belli ac Pacis (1625), which is justly renowned for the part it played in the emancipation from religion of knowledge about man and society ( §2). Economic issues (including money loans) were introduced mainly in Book II, where Grotius discussed the causes of the birth of war and, in a more systematic way, in chapter 12 on contracts.

His sophisticated theory of "acts", borrowed from Roman law, was introduced in chapter 12 on contracts, and he used it in order to challenge Thomas Aquinas's classical argument against usury ( §3). Whereas he inherited at least part of his predecessors' repugnance of interest lending, he relied on the "acts" involved in transfers of 1 The question of knowing when this long maturation reached its conclusion is still disputed. Noonan, for instance, argued that most of the criticism against the doctrine of usury was performed during the second half of the 16th century, with Conrad Summenhart (see Noonan 1957, pp. 341-345), before the same line of argumentation reappears in the following century. O. Langholm, alternatively, supported the idea that this was performed in the continuation of the School of Salamanca, by such authors as Molina and Lugo (Langholm 1998, pp. 74-76).

ownership or use and on a discussion of the respective properties of the various types of contracts in Roman law, to criticize the main features of the Scholastic argument on the necessity of the mutuum, to remove doubts about the legitimacy of extrinsic titles, and to provide an alternative analysis of interest loans in which the income received by the lender is both explained and legitimate ( §4).

Hugo Grotius after Scholasticism: a radical extension

Whereas the works of Hugo Grotius are well-known to lawyers and philosophers, with a focus on his role in the emergence of modern theories of natural law (see, for instance, K Haakonssen, 1996) or his views on such issues as punishment or international relations (R. Tuck 1999), they are far less familiar to economists 2 . A possible source of this lack of interest might come from Schumpeter's sweeping judgement, likely to deter further investigation:

Hugo Grotius […] was first and last a great jurist whose fame rests upon his outstanding performance in international law. He dealt but briefly with economic subjects, such as prices, monopolies, money, interest, and usury in [De Jure Belli ac Pacis (The Law of War and Peace), 1625] Book II, ch. 12very sensibly no doubt but without adding anything of note to the teaching of the late scholastics. (J. Schumpeter 1954, p. 112).

Despite the severity of his judgement, which may have had some responsibility in the lack of interest in the economic aspects of Grotius's writings, Schumpeter made a point of stressing the connection with his scholastic predecessors. Hugo Grotius, a Protestant jurist, was himself a student of the Belgian Jesuit Leonard Lessius. The latter had been taught in Rome by Francisco Suárez, who was one of the leading figures of the socalled School of Salamanca. Issues relative to prices, money, interest and competition had become sufficiently important in Salamanca that, despite the differences, it was possible to recognise the constituent features of a genuine school in economics, as it already was in philosophy and theology (M. [START_REF] Grice-Hutchinson | The School of Salamanca. Readings in Spanish Monetary Theory[END_REF]. It was clearly the School of Salamanca that Schumpeter referred to when speaking of the "late scholastics". For a long sixteenth century, the thinkers of the University of Salamanca, 2 Yet, some interest appears in the scarce references to such issues as Grotius's understanding of price (A. [START_REF] Lapidus | Le Détour de Valeur[END_REF], his influence on the birth of Scottish political economy (I. Hont 1990), his conception of poverty (J. Salter 1999), his doctrinal position on free trade (P. [START_REF] Borschberg | Hugo Grotius, the Portuguese, and Free Trade in the East Indies[END_REF]C. Suprinyak 2022) or the way he articulates economic issues, like the money loan, and a normative legal concern (A. [START_REF] Lapidus | Le Prêt à Intérêt Face à la Religion et au Droit. Imbrication et Séparation aux Premiers Moments d'une Histoire Longue[END_REF]. and later of the University of Coimbra, had intellectually nourished the Counter-Reformation. A remarkable instrument of this operation was the substitution of Thomas Aquinas's Summa Theologiae for Peter Lombard's Liber Sententiarum as a basic reference in the education of the clerks. Such revival of the most eminent figure of thirteenth century scholasticism, Thomas Aquinas, was far from self-evident: it came after a long eclipse of an Aristotelian realism, the via antiqua, of which Thomas had been one of the most eminent representatives, in favour of a via moderna, illustrated for instance by the nominalism of William of Occam (Gilson 1944, p. 712).

It is therefore clear that one cannot deduce from the existence of this link between Aquinas and one of the founders of the modern theories of natural law that the legacy of the former on moral, political and economic matters was passed on, without transformation, to the latter (see Lapidus 1986, pp. 45-49;2021, pp. 102-111): on the one hand, Grotius's approach to knowledge regarding human beings and society might be viewed as a kind of radical extension of Thomas's approach; but, on the other hand, on such topics as those regarding economic matters, the break could be deeper.

The Prolegomena with which Grotius's major work, De Jure Belli ac Pacis [The Law of War and Peace], begins, combine numerous references to Roman law and to ancient authors. Among the latter is Aristotle, who "deservedly holds the foremost place", although his preeminence had, "ages ago, been converted by others into a tyranny" (De Jure,Prol.,42]) 3 . To these should be added the thinkers of Salamanca, such as Vitoria, Covarruvias and Vasquez, whom he cites and discusses (for instance, De Jure,Prol.,37,55) and, more generally, the Scholastics, to whom he pays tribute in spite of the religious opposition:

The Scholastics, who followed them, often show how much talented they are […] Nevertheless, when they agreed about some moral matter, they were seldom in error; since they were very perceptive to see what may be criticized in the sayings of others. And even in their enthusiasm for contradicting one another, they provided a praiseworthy example of modesty: for they fought among themselves with reasons and not with the insults which defile contemporary literature, and are the shameful products of impotent minds. (De Jure,Prol.,52). 3 The edition used of Hugo Grotius's De Jure Belli ac Pacis is that by J.B. Scott in 1913, which reproduces the 1646 edition, published just after Grotius's death. Each time it seemed faithful enough to the Latin original, the translation of Grotius's quotations hereafter relies on F.W. Kelsey's translation into English of 1925. References are given according to the numbering for chapters, sections and sub-sections in Kelsey's translation.

References to Aristotle and the Scholastics offer evidence that this ancient affiliation was claimed (see also Grotius's biographer, Knight 1925, pp. 210-21 andSaint Leger 1962, pp. 45-57). An affiliation which nevertheless serves as a support for the emergence of what was already in the making in Thomas: by proposing, as is well known, to found faith in reason, he could retrospectively be viewed as having opened the way to a separation between the one and the other. On first view, Thomas's position amounted to giving reason and nature a prominent place in the explanation of what was previously the domain of faith. In question 9 of Quodlibet 4 on intellective power, after having, in the respondeo of article 3, considered from a rhetorical standpoint the problem of choosing between the argument of reason and the argument of authority according to the audience one is addressing (the Jews, the Manichaeans or the Greeks), Thomas concluded by discussing the way in which an argument should be conducted, this time within the Schools, between people who share the same faith. He then observed:

[T]here is a magisterial argument in the Schools, not to remove error, but to instruct the audience so that they may be brought to an understanding of the truth they believe in. And then it is necessary to rely on reasoning which seeks the root of truth and enables one to know how what is said is true. Otherwise, if a teacher decides a question by mere authorities, the hearer will be assured that such is [the truth], but he will acquire no knowledge or understanding and will retire empty. (Quodl 4, q. 9, a. 3, resp.).

The importance of this position should not be underestimated. The risk to the Church was tangible. It was the same one that had already crossed over into Islam and was now threatening the training of its clerks. Through the intermediary, in particular, of a master of the Faculty of Arts in Paris, Siger of Brabant, the theses of the Arab philosopher Averroes (Ibn Rashid) had penetrated the Parisian schools. The threat they posed was the so-called doctrine of the "double truth": the truth of faith and the truth of reason.

Averroes imposed a radical separation between the two. However, what was in the making was that if you had two truths, there was one you could do without. And as scary as this possibility seemed, it could be the truth of faith.

Yet it is this scary possibility that was achieved, three and a half centuries later, in the work of Grotius. Knowledge about human being and society there appeared sufficiently mature for the religious authority of faith and revelation to be set aside in favour of the authority of reason. Grotius announced this with infinite oratorical caution, after having pointed out how two conceptions of natural law, narrow and broad, were related:

And what we have just said would have its place even if we were to concede, what we cannot concede without the greatest wickedness [etiamsi daremus, quod sine summo scelere dari nequit], that there is no God, or that human affairs are of no concern to Him. (De Jure,Prol.,11).

The apparent radicality of the "impious hypothesis", the possibility of the non-existence of God [START_REF] Crowe | The "Impious Hypothesis": A Paradox in Hugo Grotius?[END_REF]) was downplayed by many commentatorsforemost among them Grotius's first French translator, Jean Barbeyrac in 1724and it would be inappropriate to see it as an expression of atheistic bias. We can even rule out the possibility of a secular inspiration by pointing out that it came from Salamanca, presumably from Vasquez (Saint [START_REF] Leger | The "Etiamsi Daremus" of Hugo Grotius: A Study in the Origins of International Law[END_REF]. But even if we put its meaning into perspective, the fact remains that by acknowledging the existence of laws of nature implanted in the reason and the heart of people, the use of faith to account for them was rendered superfluous.

These unwritten natural laws claimed by Grotius still hold sway, even in the situation where no law might be thought to exist, in the state of war where civil laws are suspended (De Jure,Prol.,26). And it is not to religion, but to reason, that we owe the knowledge of these "laws which are perpetual and appropriate to all times" (Ibid.). That is to say, the source of the natural law is the consistency of our actions with our humanity, as rational and as social beings:

Natural law is the dictate of right reason, which points out that an act, according as it is or is not in conformity with rational and social nature, has in it a quality of moral turpitude or moral necessity (De Jure,I,10.1).

And, as Grotius put it, it is only "consequently [consequenter] [that] such act is forbidden or commanded by God, the author of Nature" (Ibid.). The argument is still strengthened by what appears as a plea against divine omnipotence, rooted in the universal truth of what will be called later analytical propositions:

Natural law is so immutable that it cannot be changed by God himself [ne a Deo quidem mutari queat]. Immense as is the power of God, nevertheless it can be said that there are certain things over which it does not extend; for if we speak of these things being done, what is said in this way is only said, it has no sense which expresses the matter, and it is contradictory.

Just as even God, then, cannot make that twice two should not be four, so He cannot make that what is intrinsically evil be not evil (De Jure,I,1.10.5).

This justifies that Grotius might rightly be regarded as a founding figure of what L. [START_REF] Strauss | Natural Right and History[END_REF] called "modern natural law" (see also [START_REF] Haakonssen | Natural Law and Moral Philosophy: From Grotius to the Scottish Enlightenment[END_REF]. By contrast with Thomas, for whom reason made it possible to find what faith had already made it possible to know, Grotius distances himself from religious imperatives in his understanding of natural law: it is no more in God that natural law finds the source of its binding force. And despite his numerous references to theologians or canonists, it is free of religious imperatives that he engages in a critical discussion of the categories derived from Roman law.

The framework and the target: typology of acts and doctrine of usury

It is from the critique of these legal categories from Roman Law that the elements of economic knowledge arise, and more particularly those concerning an understanding of interest loans which could be traced back to the works of Thomas Aquinas.

The legal typology of acts and economic issues

The economic developments are mostly found in Book II of the Law of war and peace, which deals with the causes of the birth of war. It is in discussing these causes that Grotius addresses collective and private property, its acquisition and transfer. And it is on the occasion of the legal examination of obligations deriving from property that he introduced the Chapter 12 on contracts, most of which being devoted to analyses of price, trade, money and interest loans.

Grounded in a Roman law perspective, these analyses are built upon a categorization of "acts", either "simple" or "mixed" (De Jure,II,12.1). Insofar as economic matters are favoured, most of simple acts fall under the heading of "permutatorial acts" (permutatorii) as opposed to "beneficial acts" (benefici) (De Jure, II, 12.2; reference was given to Aristotle's distinction between two ways of alienation, "gift" and "sale", in footnote a), even though some of them could be seen as proceeding from the so-called beneficial acts "with mutual obligation". The latter refer to what was called "real contracts" in Roman law, typically when "some effect remains". Among them, he places, for instance, the commodatum (that is, the loan for use, in which the lender keeps the ownership of his good and gives its use for free.), the commission or the deposit (Ibid.). Following the Roman jurisconsults, Grotius regarded permutatorial acts as divided into acts that "separate the parties" (dirimunt partes) and acts that "produce a community" (communionem adferunt) (De Jure,II,12.3.1). Typically, acts that produce a community refer to firms through, for example, the contract of society (societas) (De Jure, II, 12.4), while acts that separate the parties cover most of the modalities of exchange as we usually conceive them (De Jure,II,12.3). Though legally distinguished, these two types of acts are nevertheless permutatorial acts, which already invites us to recognise the continuity established between exchange, strictly understood, and organisation as alternative methods of allocation.

This also shows how working on legal categories produces economic categories, as if Grotius's task was to make obvious that the borders usually acknowledged between legal categories were porous enough to allow economic reasoning to cross them. This is further evidenced by the way in which Grotius introduced exchange (commutatio). The latter arises from the criticism of the distinction in Roman law between the so-called "nominate" (nominatos) contracts, which are allegedly the oldest, and the "innominate" contracts, which are more recent (De Jure,II,12.3.2-3): Grotius likened "barter" (permutatio) to "purchase and sale" (emptio ac venditio), emphasising that although nominate, the latter (where goods are exchanged for money) is more recent than the innominate former (where goods are exchanged for each other). So much so that natural laws would invite us to look in the same way at all the contracts (nominate and innominate) amounting to exchange ("permutatorial acts", in Grotius's words), in which the "giving" or the "doing" of one side meets the "giving" or the "doing" of the other side (De Jure,II,12.3.3) in a combinatorics drawn from the Digesta (lib. XIX, tit. 5.5) that, from an economic point of view, could pretend to be exhaustive.

For instance, with regard to contracts in which one party gives so that the other party also gives, barter (permutatio) is the giving of one thing so that another thing is given; buying and selling (emptio ac venditio), the giving of one thing so that money is given; change (cambium), the giving of money so that money is given; lease (locatio), the giving of the use of a thing so that money is given (De Jure,II,12.3.4). Completing this picture with contracts in which one party is doing in order that the other party should give or do, allows introducing renting (Grotius again uses the term locatio) or insurance (assecuratio)the recent favour of which at his time he pointed out (De Jure,II,12.3.5). Finally, he introduced the possibility of "mixed" acts that combine simple acts, permutatorial or beneficial (De Jure,II,12.5). This typology is remarkably efficient, since it covers the variety of bilateral transactions. Among them was the money loan, whose standard treatment, as it was known in medieval times, typically in Thomas Aquinas (see [START_REF] Chaplygina | Theorizing Interest: How Did It Begin? Some Landmarks on the Prohibition of Usury in the Scholastic Economic Thought[END_REF], was directly challenged.

These elements are summarised in Figure 1 below.

How was usury prohibited: back to Thomas Aquinas

It is well-known that the prohibition of usury was viewed, in an Aristotelian tradition, as derived from the sterility of money (see, within a wide literature, [START_REF] Langholm | The Aristotelian Analysis of Usury[END_REF]. But the legal basis of the classical argument regarding usury in money loans was a contract borrowed from Roman law, called the mutuum (Digesta, lib. XLIV, tit. 7.4). The mutuum was a loan contract in which property and use are transferred for free. It is therefore obvious that if a money loan is made through a mutuum, the lender is not entitled to any payment on account of the loan contract itself. Paucapalea, who was around 1165 the first great commentator of Gratian's Decretum, initiated this approach to money loans, assuming the legal framework of the mutuum, and relying on an alleged etymology of the word to explain why the lender should not receive any return for his or her loan:

A mtuum is so-called from this, that mine become yours [Mutuum ex eo dictum, quia quod sit meum fiat tuum]. That is, a mutuum is consisting in the quantity that is advanced to you, and I will receive back from you the same amount of the same kind. (Summa super Decreto Gratiani, c.14, q.3)

The argument was later systematically repeated, by Robert of Courçon, for instance (De Usura,15), in the first years of the 13th century, till Thomas Aquinas who provided reasons why the mutuum was not an arbitrary choice among the alternative possibilities offered by civil law (besides the mutuum, a foenusin which both ownership and use are transferred by the loan, but this time not for free -, a commodatum or a locatio), but a necessary contract for money loans. His position can be found in a famous passage from question 78 of the IIa-IIae of the Summa Theologiae (on earlier treatments of usury in Thomas Aquinas, see Januard 2021):

One must know that the use of certain things is identical with their consumption: thus we consume wine when we use it for drink and we consume wheat when we use it for food. In such [exchanges], one must not count the use of the thing apart from the thing itself but, as a result of conceding the use, the thing itself is conceded. And this is why, for such things, the loan [mutuum] transfers property. Thus, if someone wanted to sell wine on the one hand and the use of wine on the other hand, he would sell twice the same thing or sell what is not […].

Conversely, there are things the use of which is not their consumption. So, the use of a house is to live in, not to destroy it. Therefore, one can concede separately use and property. (Summa Theologiae, IIa-IIae, q.78, a.1, resp.; see also in De Malo q.13, a.4c).

The conclusion is straightforward. Since it seems impossible for money, like for wine, to separate its property from its use, the loan contract cannot be i) a locatio in which only the use of the good only is transferred and sold to the borrower; ii) a commodatum, which might be viewed as a kind of locatio, but for free; iii) a foenus either, since it would amount to sell to the borrower a use which he already owns along with the property of the money lent, during the time of the loan. So that money, like wine or bread, can only be lent for free, through a mutuum and there is no room for an interest paid to the lender in reason of the loan itself.

It is obvious that the classical argument gives a firm analytical basis to the prohibition of usury, in the sense that if it is "rightly blamed and loathed" (Politicorum, I, 8), it does not depend on a disputable moral perception or on arbitrary legal grounds: it is a fault against reason, so that the income received by the lender (if any) cannot be explained by the loan granted to the borrower. Butand this point should be stressedwe must take this conclusion cautiously: it does not forbid all alternative possibilities and explanations, acceptable in reason as well as according to moral and legal standards (see Chaplygina and Lapidus 2016a, pp. 35-39;2016b, pp. 62-74;2022, pp. 98-101).

Such possibilities arose from the fact that money lending, as an exchange over time, was generally recognised as mutually advantageous for both the lender and the borrower (see, for instance, Summa Theologiae IIa-IIae, q.77, a.1, resp.), so that the situation of none of them could be made worse off. Whether the loan was usurious or lawful depended on the way this advantage was distributed between the lender and the borrower. Given that the loan contract, by nature, forbids any interest, the key of distribution of the surplus should rest on other considerations. The latter were expressed in terms of "extrinsic titles"extrinsic to the loan contractor of substitutes to the money loan. Aquinas, for instance, made clear that extrinsic titles were founded on the compensation of a prejudice suffered by the lender:

In his contract with the borrower, the lender may, without any sin, stipulate an indemnity to be paid for the prejudice he suffers while being deprived of what was his possession; this is not to sell the use of money, but to receive a compensation. (Summa Theologiae, IIa-IIae, q. 78, a. 2, ad. 1).

The literature on usual extrinsic titles, such as poena conventionalis, damnum emergens or lucrum cessans, is extensive (see, among others, the early but unrivalled contributions of McLaughlin 1939, pp. 125-147, andNoonan 1957, pp. 105-132;and, for a recent account, Januard 2022a, p. 750). Beyond an acceptance in principle, the debates surrounding them show that whereas some of them (typically, the poena conventionalis) raise few objections, others (such as the lucrum cessans for Thomas Aquinas) arouse mistrust, all the more so because they involve professional merchants as lenders. The existence and the place of extrinsic titles within a construction aiming at prohibiting usury should not be underestimated. It was a definite break with a conception illustrated by Raymond of Pennaforte, secretary of Gregory IX and later General of the Dominican order, who argued in his Summa casuum conscientiae (ca 1236) that in certain cases, usury was allowed (McLaughlin 1939, p. 85;Noonan 1957, pp. 102-103;Hamelin 1962, pp. 85-86). For Thomas, usury was in no way allowed, and if a supplement is given to the lender, it is not because of the primary loan contract, but because of external reasons, pointing to the compensation of an opportunity cost suffered by the lender, expressed in extrinsic titles. After Thomas, and till Lessius's introduction of the carentia pecuniae in 1605, the range of extrinsic titles was to increase, and their allowance became broader. Typically, for instance, Alexander of Alexandria introduced the periculum sortis in his Tractatus de Usuris (1307) and systematized the use of extrinsic titles. So that the Scholastic understanding of money loans combined an analytical core consisting in an exchange in time bearing no interest, and complementary devices allowing interest as a compensation for the prejudice suffered by the lender.

Interest without usury

It is this whole construction that is called into question in Grotius's work. His argument can be reconstituted in two stages, although these do not strictly follow the order of the presentation. The first stage extends and systematises the transformations concerning the classical argument on usury (supra, §3.2), after Thomas's death, and the resulting consequences for the appreciation of extrinsic titles. The second stage relies on the typology of acts sketched at the beginning of chapter 12 (supra, §3.1), in order to rid the understanding of interest loans of the limitations attached to the prohibition of usury.

A deconstruction of the classical argument against usury

The issue of interest loans and usury is tackled head-on in sections 20 to 25 of this same chapter 12 of Book II. Some of the developments could lead to finding at least the conclusions, even if qualified, of his medieval predecessors. Thus, after having, in section 20, multiplied the arguments against the scholastic position on usury, he considered, based on the Old Testament, that the prohibition of usury is "if not necessary, at least morally honest" (De Jure,II,12.20.3). Within a section that discusses the question of under which lawscivil or naturalusury would be possibly prohibited, the reference to necessity and moral honesty is significant of Grotius's own repugnance to interest lending. A repugnance that was less forceful than that of his predecessors, with more terminological nuances with regard to the vocabulary of his time and its alleged evolution, but which was no less assumed. Thus, he explained in a footnote:

If we want to speak like the jurisconsults of Roman law, the name "foenus" is odious, but not that of "usura" [foenus odiosum nomen est, usura non item 4 ]. [...] But as most people have abused "usura", this word has begun to be taken in the wrong way: it has been substituted, in a good sense, for the word "interest" (De Jure,II,12.21 n. 2).

Nonetheless, this repugnance did not mean that the income perceived by the lender was contrary to natural law. It is therefore not because it fits in with civil law, but because it does not contradict the rational and social aspects of human nature, that Grotius gave the example of the Dutch legislation which allowed, consistently with natural law, that a non-merchant received 8% on a loan and a merchant 12% (De Jure,II,12.22). So that it escapes the analytical construction which, in Thomas Aquinas, supported both the explanation of a specific income associated with an interest loan and the prohibition of usury. In contrast, Grotius brings out the elements that allow the mechanism of interest loan to be dissociated from its negative normative assessment. The contractual nature of the permutational acts to which the money loans belong makes it obvious that they are inherently mutually advantageous operations, so that the question is again for Grotius, like for Scholastic authors before him, of knowing how these advantages should be allocated between the borrower and the lender. However, not only is the sophisticated device that was intended to prevent usurious transactions missing, but its components are all neutralized. 4 Kelsey's translation, on this point, does not really help to resolve the ambiguity: "the name of usury is hateful, but not in like manner interest". All the more so since the end of the note is quite faithful to the Latin original: "Because many have misused the word usury […] the word interest is substituted for it in the good sense" (De Jure,II,12.21

n. 2).
The operation is performed in the two first sub-sections of De Jure, II, 12.20, where Grotius discusses the three issues which might lead to the conclusion that usury is prohibited by the law of nature. He therefore: i. justifies the possibility of moving from a mutuum to a foenus for a money loan;

ii. rejects the Aristotelian argument on the sterility of money;

iii. claims that in a money loan, the whole ownership is not transferred to the borrower.

The first argument, invoking in a footnote (De Jure,II,12.20.1,n. 1) the authority of the Codex of Justinian, is that the mutuum is to the foenus what the commodatum is to the locatio. Though he is not quoted, it seems obvious that the source of the "more generally accepted opinion" which Grotius challenges can be found in Huguccio Pisanus who, commenting on Gratian's Decretum, claimed around 1190 that, although a move from commodatum to locatio was licit, the parallel move from mutuum to foenus was not:

But in this, it is appropriate that both the mutuum and the commodatum should be gratuitous.

If, therefore, something beyond the lot is demanded for the mutuum, whatever it may be, it is usury, and in this case only usury is committed, namely, when something is demanded or accepted for the mutuum beyond the capital. If, however, something is demanded in return for the commodatum, it is not usury, but it is no longer the commodatum, but another contract, that is, barter [permutatio], or locatio, or sale [venditio] (Summa Decretorum, C. 14, q.3, dictum ante c. 1;quoted by McLaughlin 1939, n. 176, p. 101; see also Noonan 1957, p. 40).

Grotius's answer is based on the acknowledged legal possibility to sell the use of a thing, so that such sale only implies a change of contract:

What is said of the mutuum, namely that it is free, can be said of the commodatum: however, it is not unlawful to demand a price for the use of the thing [pro usu rei pretium exigere illicitum non sit], and all what happens is that it only changes the name of the contract [for foenus in the first case, locatio in the second] (De Jure,II,12.20.1).

This means that if we accept the idea that a good which is the subject of a commodatum can just as easily be subject to a locatio which also transfers use but for a reward, we can also accept the idea that a good which is the subject of a mutuum can in the same way give rise to a foenus which transfers both use and ownership, but this time for a reward.

The second argument challenged by Grotius is this, borrowed from Aristotle, of the sterility of money. He had developed an interesting conception of money, at odds with that of Aquinas in his comments on Aristotle's Politics (Politicorum, I, 7) who saw it as the result of a convention (see [START_REF] Lapidus | Metal, Money, and the Prince: John Buridan and Nicholas Oresme after Thomas Aquinas[END_REF]: he understood money as a good like any other, whose value, constituted by the metals of which it is made, would simply be more stable over time than that of other goods (De Jure,II,12.17). Of course, the idea of a greater stability might be discussed, but since money is also a good like, say, a house, its fruitfulness does not depend anymore on its own nature but, like this of a house, of what we have done of it. After relying, as often, on the authority of the Digest, Grotius concludes:

The argument is not more convincing, that money is by its own nature unproductive. For houses and other things, barren by nature, are rendered fruitful by the industry of men (De Jure,II,12.20.1).

The third and last argument questioned in the same subsection is at the heart of the Thomistic conception of money lending, since it deals with the impossibility of separating use and ownership when money changes hands and the resulting impossibility, in reason, to understand a money loan in another framework than this of a mutuum:

This is more plausible [speciosus] that here [for a money loan], the thing is returned for the thing; that the use of the thing cannot be distinguished from the thing when the use of the thing consists in using it up [in abusu consistat]; and that nothing ought to be demanded for such use (De Jure,II,12.20.1).

Grotius's reply can be complemented thanks to a long footnote of Jean Barbeyrac in his translation into French from 1724. Barbeyrac had noted that Grotius already replied to the ownership argument in his Annotationes in Novum Testamentum, some years ago 5 , when commenting on the well-known passage of Luke which urged "lend, hoping for nothing again [in the Vulgate: mutuum date, nihil inde sperantes]" (Luke 6:35). Both the Annotationes and the De Jure conclude that a shift from the mutuum to the foenus for a money loan is not only possible but also well-founded, as is the reward for the lender that follows.

5 Less than 20% of Grotius's comment on Luke 6:35 are translated in Barbeyrac's note. The Annotationes were presumably written in 1619-1621, although they were first published only in 1641. See H.J. De Jonge 1984, pp. 97-99. • Assume now that ownership and usufruct has been redefined in accordance with Grotius's reasoning. If so, a man will be supposed to be richer because he has been given the usufruct of a sum of money, but not its ownership. This shows that such usufruct has a price.

So that he felt entitled to conclude that Wherefore it must be so held, that it is not contrary to nature that he who deprives himself of the use of his money in favor of another may, in return, negotiate beforehand that the borrower shall give something in return for that service (Annotationes, Luke 6:35).

Grotius can therefore understand interest as a magnitude depending on the duration of the loan, which can be paid with the profits of any operations carried out by means of this loan: So also, the right of repaying money or wine borrowed only after a certain time is something capable of being evaluated: for he pays less who pays late. Also, in an antichresis [a mortgage], the use of money is compensated for by the fruits of an estate (De Jure,II,12.20.2; see also Annotationes, Luke 6:35).

These few sentences reduce the previous deliberate gap that could exist between consumption-related and profit-making transactions. It is indeed remarkable that Grotius did not make a break between an explanation of interest based on a preference for present (one pays less when one pays laterthe present value of a forward payment is less than the cash value of the same payment made today) and an explanation based on profit (the "fruits of an estate"the present value of a sum of money available today is less than the present value, after one year, of the fund obtained by having invested this sum). The old distinction between consumption loans and the financing of a commercial or manufacturing enterprise has now been replaced by identical treatment.

At the same time as acknowledging that a price is now assigned to the usufruct of a sum of money, this ending of the gap between consumption loans and investment loans has radical consequences for extrinsic titles.

On the one hand, the more or less pronounced reservations about extrinsic titles, as already encountered in the works of the Scholastic authors, are now suppressed.

Grotius's position was introduced in a discussion of the "common price", upstream of the passages strictly devoted to interest loans when, considering the possibility of a gap between the availability of a good and its payment, he unambiguously established the possibility of [...] taking into consideration the damage or loss of profit [damni aut lucri cessanti], which arise from delayed or anticipated payment (De Jure,II,12.14.2).

The same argument is then used to absolve what might appear to be usury in a framework that is explicitly designated as this of the mutuum, so that the comment is clearly about extrinsic titles: It must be observed, however, that there are certain things which look like usury, and are generally viewed like usury, although they are agreements of a different kind: what is stipulated, for example, as compensation for the damage [damnum] suffered by the one who has lent money [qui pecuniam dat mutuam], because he will be deprived of it for a long time, or because he will lose, because of the loan, the opportunity to make a profit [item de lucro ob mutui dationem cessante] [...]. [...] and for the danger of losing the capital [pro periculo amittendae sortis], when no sufficient guarantee is given, is not really usury (De Jure,II,12.21).

Extrinsic titles are not explicitly named, but it is clear that they are at issue and now free of any usurious potential. Damage incurred because the lender has to forego consumption or profit (poena conventionalis, in case of delayed payment; damnum emergens, and even lucrum cessans during the term of the loan), because he is exposed to risk (ratio incertitudinis) or even because he is lacking money (carentia pecuniae), is sufficient reason for it to be compensated by interest paid by the borrower. But, on the other hand, though the reasons expressed in extrinsic titles still hold, the extrinsic nature of these titles is seriously threatened. Extrinsic titles were so called because the damages invoked were not directly involved in the main contract, the mutuum. They were a compensation for opportunity costs, suffered by the lender, not the acknowledgement of an income generated by a persistent ownership benefiting the lender. But now? Grotius's redefinition of ownership as including the "right to receive the same thing in kind" allows considering that the reasons for extrinsic titles depend on the new right which benefits the lender: all reasons for interest being paid now depend on the loan contract itself: the mutuum has moved into a foenus. For Thomas Aquinas, the legal determination of the loan contract amounted to "trading for no price"even if something like a price might appear for other reasons [START_REF] Januard | Trading for no price, Thomas Aquinas on Money Loans, Sacraments and Exchange[END_REF]. With Grotius, a shift in the determination of legal categories allowed trading for a price.

Substitutes for money loans and mixed acts

The Scholastic conception of usury came up against the existence of close substitutes for interest loans, which are known to have given rise to recurrent controversies. They were the result of the tension between a non-interest-bearing mutuum and the numerous interest-bearing financial arrangements, acceptable in principle, provided their intention was not to circumvent the prohibition of usury. It is clear that the abandonment of the necessity of the mutuum as the legal framework for money loans reduced, if not cancelled out, this tension. Yet, Grotius discussed these close substitutes for themselves, independently of his conclusions about the mutuum. The societas and the foenus nauticum illustrate this point.

What appears, typically in Thomas Aquinas, is that the existence of a non-usurious intention is sought through its material expression. The various financial arrangements were only deemed non-usurious if the income they generated for the lender could be justified by uninterrupted ownership, possibly evidenced by risk-taking in case of loss.

This can be illustrated by the contract of societas. In Roman law, it could take the most diverse forms, whereas only some arrangements were acceptable for Thomas 6 . Grotius was obviously more open to a diversity of possible contracts. But he also did so through a link established, like for his predecessors, between ownership and risk.

In dealing with societas, he considered the various types of combinations between partners who alternately bring money or industry in whatever proportions. The way money is introduced in the societas is of special interest. Relying on the writings of theologians of Salamanca such as Navarro or Covarruvias and on the authority of his master Leonard Lessius, Grotius distinguished between the two ways of introducing money into a partnership: either as a transfer of both the ownership and use, or as a transfer of use (the principle of which no longer raised any objections):

But this comparison [of industry and money] is not done in one way: for either industry and the use of money alone [cum solo pecuniae usu] are the relative contributions […] or industry and the ownership of money itself [cum ipso dominio pecuniae] are the relative contributions (De Jure, II, 12.24.2). 6 P. Januard (2022b, pp. 247-249) discusses alternative interpretations of these arrangements leading to a societas in the works of Thomas Aquinas: an "activity-based" approach, illustrated by R. Ege (2014, p. 403) and an investment-based approach (Chaplygina and Lapidus, 2016, p. 37).

Like with his predecessors, the criterion of ownership was the basis for the income of each party, since ownership of a fraction of a stock entitles one to the same fraction of the profit or obliges one to bear the same fraction of the loss, even for the partner who would have contributed only with money:

In a societas, when the contribution consists on both sides of money, if the sums are equal [si pecuniae aequales sint], the [shares in the] loss and in the profit [in damno et lucro] must also be equal; if they are unequal, the shares will also be in proportion […] And the same will take place if equal or unequal industries [operae] are compared. But also industry can be brought together with money, or with money and with industry (De Jure,II,12.24.1).

This analysis would lead to seeing an interest loan in the operation carried out by the partner who is providing money, except that the latter also participates, and in the same proportions, in the loss. This approach may seem, at its beginning, close to that of the Scholastics. All the more so since a limit case of the societas was, in first view, excluded of the range of acceptable contracts: when one of the partners participates in the gains but not in the losses: such arrangement, Grotius says, "is against the nature of societas" (De Jure,II,12.24.3). But, this time in contrast with his predecessors, he did not conclude that such agreement should be rejected. He only claimed that strictly speaking, it was no more a societas, but a "mixed contract", of societas and of insurance, for which he gave the conditions of acceptability: Under such conditions, the agreement will become a mixed contract of societas and insurance against loss, in which equality will be preserved if the one who has taken upon himself the risk of loss shall receive an equivalent increase in profit over what he would otherwise have received (De Jure,II,12.24.3).

The nature of this limit case of societas is now clear. Relying on the typology of human acts which Grotius introduced at the beginning of chapter 12, a societas in which one of the parties does not participate in the losses is a mixed act, which combines two simple acts (see also supra, Fig. 1): a societas, which is a permutatorial act involving the community of the parties (De Jure,II,12.4), and an insurance, also a permutatorial act, but involving a separation of the parties of the type doing (protection) / giving (money) (De Jure,II,12.3.5). Note that in this case, whereas the income received by the partner who bears the risk of loss is indeed interest on the money or the industry he has advanced, a risk premium is deducted, which is added to the interest received by the other party.

A similar role of risk can be observed in Grotius's discussion of the sea loan, the foenus nauticum. Regarded as a substitute for an interest loan, the foenus nauticum had been the subject of countless debates in previous centuries (Lapidus 1991, pp. 32-34).

But with Grotius, this rather complex arrangement, whose non-usurious character depended on the possibility of an uninterrupted ownership, became, like in the limit case of the societas, an elementary combination, within a mixed act, between two simple acts: a mutuum in which money is given in return for the subsequent return of the same amount of money and, again, an insurance in which money is given in return for the compensation of a peril if it occurs: So, the sea loan is a mixture between a contract of mutuum and an insurance [foenus quoque nauticum mixtum quid est ex contractu mutui, et periculi aversi]. (De Jure,II,12.5).

If so, Grotius's treatment of the foenus nauticum does not lead to an understanding of the income received by the lender as interest, but as a risk premium paid by the borrower. Stated differently, this is not strictly a price of time, but a price of risk.

Concluding remarks

From Thomas Aquinas to Hugo Grotius, the repugnance to interest loans has at least persisted. As if the "bite", which R. [START_REF] Ege | La Question de l'Interdiction de l'Intérêt dans l'Histoire Européenne : un Essai d'Analyse Institutionnelle[END_REF] had shown how it crossed the three monotheisms from Antiquity to the Middle Ages, could in the same breath also cross the centuries. The practical incidence of such repugnance might obviously be discussed, and it seems obvious that for so long, the existence of interest-bearing loans had become increasingly important in business life.

But with Grotius, something changed in the way interest loans were not necessary felt but understood. In a way, it might always be argued that such or such idea of Grotius on money loans was borrowed from Lessius, Covarruvias, Odonis, Olivi, Alexander of Alexandria or directly from canon law. And this was paradoxically confirmed by Grotius himself, who seems to have taken pains to find precursors, as if to reduce the originality of his argument. But the result is an impressive intellectual construction that directly challenges the conception of money loan and usury inherited from Thomas Aquinas. From the periphery to the core, the challenge concerned the substitutes for interest loans, illustrated by the contract of societas and the foenus nauticum, whose usual provisions were recognised; the extrinsic titles, whose extent became increasingly wide; and the requirement of the mutuum, which was no longer necessary because not all ownership passes from the lender to the borrower. This was carried out on the basis of a critical reflection, free from religious requirements, on legal categories from Roman law: the different kinds of loan contracts; ownership; usufruct; the typology of human acts. And it is by shifting or rendering porous the boundaries of these legal categories, by altering their content, that he allowed for the transformation of an economic reasoning that now gave way to a renewed understanding of money loans.

Figure 1 :

 1 Figure1: Typology of acts and economic transactions(Grotius, De Jure Belli ac Pacis, II, 12)

Acknowledgements

I am grateful to Laurie Bréban and Pierre Januard for their remarks and discussions at an earlier stage of this paper. The comments and criticisms of two referees of this journal were particularly valuable and helped me to clarify and strengthen my argument.

Nonetheless, the usual caveat remains.

Grotius's case in the De Jure is developed in the next subsection (De Jure,II,12.20.2), in which he reconsiders the possibility of separating the use of money from its ownership in the case of a money loan, and draws the consequences for the income received by the lender. By arguing that the lack of separation between usufruct and ownership in the case of perishable goods stems from the way in which the word "usufruct" itself is understood, he allows for an expanded understanding of this usufruct for which Whewell, in his translation of 1853, spoke of a "quasi usufruct": if this expanded usufruct enjoyed by the borrower remains dependent on an ownership which the lender has not divested through the loan, the lender has a right to a specific income.

Obviously, this can be related to the already mentioned bull promulgated in 1279 by Pope Nicholas III and incorporated in Canon law (Decretales,Liber Sextus,V,tit.11,c.3, Exiit qui seminat) for which consumption might remain separate from an ownership which can become the object of a transaction, even in the case of money. Consequently, the lender now becomes entitled to claim compensation because of the loan itself:

[I]f anyone should yield such a right to the owner [an ownership from which is derived the expanded usufruct], money could be demanded on that account (De Jure,II,12.20.2).

The comments on Luke make obvious the way in which Grotius understood this specific right, in a money loan, which works likewhich rigorously isan ownership, and allows the lender to receive a reward:

Others insist that the mutuum transfers ownership; so the fruit arising from a thing ought to belong to the owner. But even this subtlety of language has nothing to do with natural equity.

For, in the case of things that may be returned in kind, as money, corn, wine, the right to receive the same thing in kind, stands for ownership (Annotationes,Luke 6:35).

Still in the Annotationes (Luke 6:35), Grotius gives some examples, which can be viewed as thought experiments, and make it tangible that such a right existed:

• He compares a man who receives au thing immediately with another who receives it much later and concludes that it is universally agreed that the first receives more.

• He then imagines another agreement, in which he lends some oxen to his neighbour for ploughing his ground. The counterpart is that this neighbour shall lend him later his oxen. Now, this obligation can, itself, be submitted to a monetary estimation (pecunia aestimari potest).