Is God Giving or Trading? Thomas Aquinas's First Use of “Just Price” Free

Abstract

The phrase “just price” first appears in Aquinas's Commentary on the Book of Isaiah (1252). Interestingly, even in this early work Aquinas introduces the notion of price to comment on a verse, a term which had in fact disappeared with the Vulgate Latin translation, on which Aquinas relied, and which does not appear in the Fathers’ commentaries. Aquinas here provides the founding elements of his later analyses: the role of the price in ensuring the justice of exchange but also the diversity of possible exchange ratios, not necessarily referring to price, in order to account for limit cases within an exchange framework.

1. Introduction

The texts of Thomas Aquinas (†1274) on economic matters are the most important of his time, both in terms of size and posterity. One of the most crucial and heavily debated points in these contributions concerns the just price, which has been the subject of a plurality of interpretations over the last hundred years. Recent literature has distanced itself from the classical debate between a cost-of-production approach and a market approach, allegedly based respectively on Ethicorum and on De emptione et venditione ad tempus or the Summa theologiae, to broaden the spectrum through the rediscovery of the primacy of justice in determining the just price.¹ Building on these works, this article continues the investigation, focusing on the first occurrence of the Thomasian expression of “just price,” when he comments on the biblical verse Isaiah 55:1.

This first use of the expression “just price” is metaphorical. Aquinas is dealing with the verse from the prophet Isaiah presenting God communicating His wisdom to mankind. This spiritual exchange might seem a long way from the exchange between human beings that economics deals with, and this founding occurrence, not appearing in a directly economic text, has not attracted the attention of economists.² It is, however, economically significant because it introduces an exchange, which does involve a counterpart but which, in order to be fair, is not made according to a price, that is, an equality between things exchanged.³Super Isaiam, 55, 1 is thus crucial in three respects: it brings a whole new dimension to medieval economic thought, it renews our understanding of Aquinas's economics-oriented writings, and it sheds new light on contemporary economic issues. Indeed, it now provides us with an analytical framework for thinking about all exchanges in which there is a counterpart and for clarifying the interactions between gift and trade in order to analyze the new forms of social economy.

Until the beginning of the thirteenth century, this verse was long understood as the expression of a free gift from God, and it is only with Aquinas that it is explicitly understood as an exchange with a counterpart. Aquinas explains the conditions of this exchange, which is made at “less than the just price”: for, indeed, mankind cannot pay a counterpart according to a price, and this means that the exchange is made according to another kind of exchange ratio.⁴ This text calls into question the very notion of the exchange ratio and sheds light on subsequent mentions of just price by Aquinas. The inaugural occurrence is innovative and foundational in that it presents a double movement: the introduction of a plurality of exchange ratios, which makes it possible to deal with numerous limit cases that are not governed by a price, and the affirmation of the price as the reference exchange ratio, even for these limit cases.

In this article, I show the innovative character of this introduction of “just price,” which is key to the reading of the verse and which seems to be a discovery of Aquinas, and of the implicit introduction of a plurality of exchange ratios in order to deal, in the context of exchange and not gift, with goods that are not exchanged according to a price. This marks a milestone in medieval economic thought, for although the notion of a just price is present in Albert the Great's text on merchants (In IV Sent., d. 16, a. 46), it takes on a new breadth with Aquinas, starting with this first occurrence. Moreover, Aquinas's analysis of exchanges that involve a counterpart but not according to price, and the distinction between the different types of remuneration to which the plurality of exchange ratios leads, is unique to Aquinas; and this may partly explain the fairly wide range of economic situations he deals with, certainly compared with his predecessors, but also compared with his successors, who confine themselves to usury and trade, and even then without distinguishing between the nature of the exchange ratios and the counterparts.

This also has several implications for understanding Aquinas's economic works.⁵ This text draws attention to the many exchanges, addressed in later works such as the Summa theologiae, that have not attracted the attention of commentators, or whose exchange ratio has too quickly been equated with a price, whereas it is more a question of a form of stipend or compensation. This founding occurrence makes it possible to understand in a new way such important transactions as the compensation of an interest-free loan and the remuneration of a merchant, a soldier, a priest, a lawyer, or a doctor. Super Isaiam 55, 1 thus introduces the functional distinction between received incomes. Finally, this occurrence emphasizes the role of the notion of price, since the exchange ratio used is expressed in relation to price, even though the exchange is not made according to a price. In later writings, the expression is used explicitly or implicitly as a reference point against which all exchange is ordered.

To highlight the founding and innovative nature of Super Isaiam, 55, 1, we need to look at the details of the text and trace the specific features of the Thomasian commentary, which introduces the lexicon of “price” (pretium) and the notion of an exchange with counterpart where its predecessors saw a gift. This leads to a historical investigation to determine what is specific to Aquinas and the sources that may have inspired him. The idea of the just price emerges gradually in Aquinas's authentic works.⁶Super Isaiam, where the very first occurrence takes place, is a biblical commentary composed while he was still a student. It appears to have been Aquinas's first major work, probably written during his first year in Paris, in 1252, prior to the Commentary on the Sentences (1254–56), where we can find his first economics-related texts on merchants and usury.

In order to grasp the innovative dimension of Aquinas's introduction of price, it is first necessary to identify possible sources of its advent (sec. 2). The first step is to explore the biblical source. Surprisingly, Aquinas employs the concept of price, pretium, twice in his biblical commentary, in the phrases “without price” and “less than the just price,” whereas pretium does not appear in the biblical verse reported by standard Latin Bibles. The textual evolution of the Hebrew, Greek, and Latin Bibles shows that while the term “price” does appear in the Hebrew Bible, it is absent from the verse in the Latin Vulgate, which became the Latin Bible of reference, including for Aquinas, where it is replaced by “exchange.” An investigation of the medieval biblical versions that Aquinas may have known does not suggest that they may have inspired his introduction of the notion of price. The second possibility is that of the patristic commentaries, from which Aquinas could have learned. The commentaries, up to the Glossa ordinaria a century before Aquinas, read the verse as a description of a gift. God is thus freely offering His wisdom. Hugh of Saint-Cher and Albert the Great, Aquinas's Dominican masters, introduce a counterpart paid by man within an exchange framework, but it remains quite allusive. The only source identified is liturgical, thanks to the study of the manuscripts of the early Dominican liturgy, where Isaiah 55:1 has one quotation in a version that is certainly very old and employs pretium. Thus the term appears, but not yet clearly the concept of price. Sources are therefore tenuous, and Aquinas seems to be breaking new ground by introducing the notion of price. The counterpart is not explicitly mentioned in Aquinas's Super Isaiam, but it appears in the later Thomasian commentaries on the verse, namely in his commentaries on the gospels of Matthew and John, where the man pays with his eloquence and study.

Three economic characteristics emerge from a reading of Super Isaiam, 55, 1 informed by later comments on the verse in In Matthaeum and In Joannem (sec. 3). First, Aquinas reinforces the paradoxical feature of the verse through his double use of the term “price”: “without price” (even if this means “without money”) and “less than the just price,” showing that the transaction is more like a barter than a gift, but where it is not so evident that there is something like a price to complete the transaction. Second, God is presented as ready to do anything to make the sale effective. For the sale to take place, the counterpart must be affordable, and the currency must be available. Third, if this leads to a sale at “less than the just price,” this means that if the exchange ratio is a price, that price is not just. Aquinas's conception of justice as a divine attribute, and the way in which the various forms of justice could be applied to God, confirm that it is not possible to imagine that God should perform an unjust act. Rather, it suggests that the exchange ratio, which is less than what the just price would be if it were a price, is of a different kind. Aquinas thus unifies the biblical traditions: the transaction is indeed an exchange, which implies a counterpart, but this exchange is made without money and without price.

Through the introduction in this early work of the concept of price and the quantitative measurement of the counterpart by the yardstick of the just price, Aquinas thus lays the foundations of his economic thought (sec. 4). Super Isaiam, often considered to be Aquinas's first theological work, is thus also his first work of economic significance. Aquinas sets up a price approach to the justice of exchange and introduces a distinction between value and price, which subsequently structured the mature economics writings but which was often ignored. He establishes a third way, between the gift and the exchange according to a price, which makes it possible to treat the transfer of many goods within the framework of exchange. Moreover, introducing a plurality of exchange ratios allows Aquinas to sketch out a functional distinction between incomes.

2. “Without Money and without Exchange”: Does Price Disappear over the Centuries?

Aquinas comments on Isaiah 55:1 by introducing the expression “just price” for the first time in his work. This verse, as we noted above, had already undergone a major textual evolution. The Hebrew version gave rise to two traditions when translated into Greek and Latin. The Septuagint and the Vetus latina contain “without money and without price,” whereas the Vulgate says “without money and without exchange.” Aquinas comments on this last version, the Vulgate, which gradually became the norm, by introducing the notion of price in two ways, although lexically it is absent from the Vulgate's verse. The interest in investigating manuscript and printed sources in order to trace the translations and uses of the verse before Aquinas is twofold. On the one hand, it shows that Aquinas confirms and accentuates the understanding that emerges from his immediate predecessors, Hugh of Saint-Cher and Albert the Great, of a situation of trade and not of gift, contrary to what the Glossa still held a century earlier. On the other hand, it stresses the innovative character of Aquinas's commentary, since no source introduces the notion of “just price,” and only a liturgical introit, a resurgence of a primitive translation, includes the term pretium, but not in the part of the verse where Aquinas introduces it in his commentary, and probably more in the sense of “money” than of “price.”

2.1. The Hebrew, Greek, and Latin Versions of the Bible: Between Exchange and Price

Isaiah 55:1 underwent changes in meaning in the course of its successive translations from Hebrew (Hebrew Bible) to Greek (Septuagint) in the course of the second century BC, then from Greek to Latin (Vetus latina) from the second century AD, and finally from Hebrew to Latin (Vulgate) at the end of the fourth century AD. These mutations are important for understanding Aquinas’s contribution, because the economic lexicon varies. The Vulgate, which prevailed in the Latin West and which was used by Aquinas and his contemporaries, gives the following text:

The key phrase, the history of which is required and which we will now examine, is “without money, and without exchange” (absque argento, et absque ulla commutatione).

The Hebrew Bible, from which Jerome edits the Latin Vulgate, contains the idea of price: “without money [כֶּסֶף kessef], and without price [מְחִיר mehiyr].” The word Kessef is one of the four Hebrew words for money. It also means desire. So it is as if money made it possible to feel desire (Ouaknin 1991: 599–601). The word mehiyr means price in the sense of payment, purchase, or pledge, that is, of an exchange as an action. Jerome has therefore translated the text faithfully, choosing commutatio for mehiyr, but has abandoned the notion of price to emphasize the act of exchange. Five hundred years earlier, however, when the Hebrew Bible was translated into Greek to give the Septuagint, the expression saw a different evolution. The Septuagint contains “without money and price” (ἄνɛυ ἀργυρίου καὶ τιµῆς), where τιµή (timè) means price in the sense of evaluation, estimation, and then value and price, as well as esteem or consideration. The translation of mehiyr by timè is also faithful, but it abandons the notion of action and exchange to insist on price in the sense of value. The Vetus latina, which designates all the ancient versions of the Latin Bible translated from the Septuagint, before Jerome's translation of the Vulgate from Hebrew, is in the lineage of the Septuagint, which it inherits. The Vetus italica, a version of the Vetus latina published by Pierre Sabatier in 1743 and which is its first printed edition, bears some differences in the Latin expression from the forthcoming Vulgate, and one of these is of particular importance. It translates the Septuagint as “without money and without price” (absque pecunia et absque pretio).⁸

We thus observe two parallel processes of evolution, of the Vetus latina from the Greek Septuagint and of the Vulgate from the Hebrew Bible. On the one hand, in the Vulgate, starting from the Hebrew and combining it with the Greek of the Septuagint, which wrote argurios (silver), Jerome prefers argentum, in the sense of coined money, currency, intermediary of exchange, where the Vetus latina wrote pecunia, which means wealth, having livestock, and then by extension money, and which refers, among the now usual functions of money, more to the reserve of value or to the standard of measurement. On the other hand, the Vulgate wrote “exchange” (commutatio) from the Hebrew, where the Vetus latina wrote “price” (pretium) from the Greek. We should therefore note the introduction of subtle nuances of meaning with the passage from Hebrew to Greek and Latin in the translation of the Septuagint and the Vetus latina, which makes a shift toward the value of the good (given by argurios/pecunia and timè/pretium), and then in the later translation from Hebrew to Latin, since the Vulgate takes up the dimension of exchange (argentum and commutatio) more contained in the Hebrew Bible. Moreover, through the term “exchange” (commutatio), the Latin Vulgate loses the notion of price, which was explicit in the polysemy of the terms mehiyr, timè, and pretium used respectively by the Hebrew Bible, the Septuagint, and the Vetus latina.

It should be noted that the translation of the notion of price (mehiyr) from Hebrew to Greek (Septuagint) and then to Latin (Vetus latina and Vulgate) is not uniform. Thus, in Isaiah 45:13, mehiyr takes on the meaning of ransom, the price to be paid for liberation: “He [Cyrus] shall build up my city, and he shall send back my deportees, without payment [mehiyr] or commission, says the Lord Almighty.” This is translated into Greek as “οὐ µɛτὰ λύτρων” (ou meta lutrôn, without ransom), taking into account the Hebrew polysemy of mehiyr. The Vetus latina translates lutrôn as pretium, that is, price in a value-related meaning. The Vulgate also writes pretium (however, Aquinas does not comment on this ransom in Super Isaiam, 45, and pretium does not appear in this comment),⁹ whereas in Isaiah 55:1 it insists on the notion of exchange through the term commutatio. This shows the specific character of Isaiah 55:1, for which the Vulgate does not keep the term “price” inherited from the Septuagint (timè) and the Vetus latina (pretium) but prefers to insist on the action of exchange rather than on the value of the goods exchanged, whereas in other places the Vulgate adopts a more value-related approach.

2.2. Patristic Commentaries: From Gift to Exchange

In order to identify Aquinas's direct or indirect sources both for the biblical version he might have read and the commentaries that might have inspired him, an overview of the Fathers’ commentaries is required. First of all, Isaiah 55:1 does not appear in Augustine's works, which are rich in biblical references. It is therefore not possible to rely on Aquinas's most usual patristic source. In addition, whereas the beginning of the book of Isaiah has received more attention, there are few patristic and medieval commentaries on Isaiah 55. However, some Fathers do quote or comment upon this verse. The Fathers’ reading of Isaiah 55:1 is primarily spiritual, but the lexicon of money and the phrase “without money” seem to hold the attention of the authors, although they do not sustain the metaphor. Furthermore, the second part of the expression, “without price” or “without exchange,” is not commented on.

The most influential and decisive patristic commentary is that of Jerome (†420), to whom Aquinas refers fourteen times explicitly in his Super Isaiam (Leonina 1974: 52*). Here Jerome uses pecunia where in his Vulgate he uses argentum in the phrase “you who have no money” (non habetis pecuniam/argentum). Then, he retains the single phrase “without money” (absque argento) in his commentary, whereas his Vulgate keeps a second term that refers to exchange (absque ulla commutatione), and his quotation of the Septuagint version translated into Latin in his commentary contains the Vetus latina version “without money and without price” (absque pecuniam et absque pretio) (Jerome, Super Isaiam, col. 548). Jerome's commentary provides two keys to understanding which remain as promissory notes. On the one hand, like most of the commentaries that would follow, Jerome's does not cover the second term but restricts itself to “without money,” thus limiting the economic metaphor. The dialectic between exchange and price from the ancient translations of the Bible does not seem to get much attention from commentators. On the other hand, the Latin lexicon of “money” remains unfixed and diverse, oscillating between pecunia and argentum.

About fifty years later, around 447 (Guinot 1980: 18), Theodoret of Cyrrhus, a Greek Father who used the Septuagint but also the Hebrew text (Guinot 1980: 44), retained from the quotation only “without money” (ἄνɛυ ἀργυρίου), passing over the second term “without price,” even though it appears in the two versions he had (the Greek Septuagint and the Hebrew Bible). We thus see that the disappearance of the notion of price is not only the result of the transition to Latin but also the result of the use of the Septuagint by Greek commentators, who do not take into account the second part of the phrase and the Septuagint's mention of price in their commentaries. Theodoret's approach is primarily spiritual: “Divine Scripture often calls ‘money’ justice” (Theodoret of Cyrrhus, Super Isaiah, 55, 1). To come without money is therefore to come without justice, that is, to be in a state of sin. God therefore invites sinners to come to him. However, after dwelling on the moral dimension, Theodoret takes up the financial lexicon, without, however, making any economic statement, except that there would be good and bad money, since people who live in iniquity are “wasted money” (ἀργύρίον ησιν ἀποδɛδοκιµασµένον), quoting Jeremiah 6:30. Indeed, the first meaning of the verb apodokimazo relates specifically to money, to the rejection of a metal after it has been put to the test. The verb is afterward applied more broadly to a candidate for office. This illustrates the assimilation of “without price” to “without money.” It reveals a lack of interest in an economics-oriented reading, which is not the object of Isaiah's verse, while at the same time it shows an understanding of the spiritual meaning of the economic metaphor, through the notion of money, used by Isaiah and Jeremiah.

Haimo of Auxerre, a ninth-century Latin theologian to whom Aquinas refers once in Super Isaiam (Leonina 1974: 52*), gives, like his predecessors, a spiritual-metaphorical interpretation of money, which for him is eloquence (Haimo, Super Isaiam, col. 1000). He quotes the expression of the Vulgate in its entirety (“without money and without exchange”), which he comments on with the gospel verse “you have received freely, give freely” (gratis accepistis, gratis date) (Matthew 10:8), which introduces, in the framework of a spiritual interpretation, a brief continuation of the economic metaphor. Where there is no commercial exchange, there must be reciprocity of gift, or rather continuation of gift, because the final receiver is not the original giver, who is God. Haimo thus suggests a distinction between the orders of exchange and gift, which occurs where there is neither exchange nor money. However, there is a counterpart toward a third party, since man must give in turn.

The more direct sources used by Aquinas—explicitly five times each (Leonina 1974: 52*)—are the Glossa ordinaria of the twelfth century, with particular attention to the interlinear gloss, and the Postilla super Isaiam of Hugh of Saint-Cher, an exegete and later a Dominican cardinal with whom Albert the Great interceded in order to send his young biblical student, Thomas Aquinas, from Cologne to Paris in 1252 to teach, in spite of his young age (Weisheipl [1983] 1993: 64).

The Glossa ordinaria contains the complete expression “without money and without exchange” in the biblical text, and the interlinear gloss reads: “Human wisdom is bought with gold and silver” (humana sapientia emitur auro et argento) and “your money [or silver] is false” (argentum vestrum reprobum est). The Glossa thus insists on the difference between human wisdom, which can be bought for money in gold or silver, and divine wisdom, which cannot. Moreover, the Glossa criticizes human money as false, in the vein of the wasted money evoked by Theodoret. The marginal gloss sets up a gift framework by taking up Haimo's gospel quotation in the same combination with a Pauline verse as found in Jerome (Jerome, Super Isaiam, col. 548): “‘By grace you have been saved’ [Ephesians 2:8] and in another place: ‘you received freely, give freely’ [Matthew 10:8]” (Gratia salvi facti estis. Et alibi. Gratis accepistis, gratis date) (Glossa ordinaria, III, Isaias, 55). It is a gift, and there is not exactly reciprocity, since there is no question of giving back to God. However, the frequent recourse to Matthew 10:8, which introduces a counterpart within the framework of the gift, lays the foundations for thinking about this counterpart differently, within the framework of exchange, and no longer insisting on the gift received free of charge but rather on the requirement to give in turn.

Hugh of Saint-Cher, in the first half of the thirteenth century, comments, “You who have no money, i.e. literally those who are poor” (et qui non habetis argentum: ad literam, id est, qui pauperes sunt) (Hugh, In Isaiam, c. 55, f. 130ra). Hugh provides a rare comment on the second term of the phrase “without money and without exchange,” saying, “Buy, do not understand it as an exchange, in which money is paid [Emite, non intelligatis de commutatione, in qua appenditur argentum], but only by the toil of the path [sed pro labore itineris tantum].” Hugh is being innovative. On the one hand, he comments on the expression “without exchange,” which is not usual. On the other hand, this does not lead him to endorse the order of the gift, but instead to understand commutatio in a restricted way as a monetary exchange and to think of a nonmonetary exchange, accessible to the poor who have no money. So, there is still an exchange, although there is no commutatio. The counterpart here is man's effort on the path of a holy life and the hardship he endures. However, the gift framework is not entirely absent for Hugh: in his commentary on the book of Revelation, as part of a meditation on the free gift, which means a gift in the absence of merit, he quotes the entire verse, but he does not comment upon it (Hugh, Super Apocalypsim, c. 22, f. 429rb).

Albert the Great, under whom Aquinas was a biblical bachelor and perhaps wrote his Super Isaiam, also composed a commentary on the book of Isaiah. This commentary was absent for a long time from editions of Albert's works and was only included in the Cologne critical edition in 1952. The dating is uncertain, but it has been estimated around 1250 (Siepmann and Simon 1952: XX). Money refers, as for Haimo, to eloquence: “Money means a ringing and resonating speech,” Albert writes (Postilla super Isaiam, c. 55, l. 26–27).¹⁰ He adds, “Those who have no eloquence must nevertheless hasten to the doctrine and grace of the Lord” (l. 30–31). It is thus a gift only in appearance, for on the one hand it means that those who have eloquence must offer it as the counterpart and that the others must come to divine grace. They must therefore do something in return for what seemed to be a gift. In this sense, Albert comments on “buy” (emite) by introducing an exchange: “by an exchange of merit in reward” (l. 45–46). Therefore, he comments on the double proposition “without money and without exchange” in two steps. The first, on “without money,” is, “He is so generous that he gives out of goodwill to the one who cannot exchange external goods” (l. 47–49). Then he comments on “without exchange”: “We can exchange nothing because we have got nothing” (l. 51–52). Albert does not say that the transaction takes place outside the framework of exchange, but simply that man has nothing to exchange. The counterpart can thus tend toward zero or be zero, but the framework of analysis is still that of exchange, since the concept of a counterpart is introduced. A few lines above, the counterpart was even nonnull since it was merit.

Although it is not a source for Aquinas, one can also refer, as a witness of the time, to William of Alton, a contemporary Dominican author. He takes up the theme of eloquence, with which money is associated in the expression absque argento in his Super Isaiam. However, he insists on the work to be done in order to acquire the milk that God gives, which is his sacred doctrine: “those who work [laborant] to acquire Your doctrine” (Madrid Bibl. Nac. 493, f. 250r and 250v; BnF lat. 573, f. 73vba). This thus takes into account the following verse: “Why do you spend your money not on bread and your work [laborem] not on satiation?” (Isaiah 55:2). Work, mentioned in v. 2, is therefore called upon in the commentary on v. 1, where it is an issue of working to acquire what is good, the divine doctrine. Through the notion of work, retained by William, the idea of a counterpart in the framework of an exchange, developed by Hugh and then by Albert, seems to persist among the Dominicans of the thirteenth century.

We can thus summarize the history of the textual tradition of Isaiah 55:1 up to Aquinas as in figure 1.

Thus, Aquinas's indirect and direct masters, Hugh and Albert, are innovative in commenting on the expression “without exchange” where their predecessors focused on the preceding expression “without money.” Paradoxically, the need to comment on the absence of exchange places them before the presence of a counterpart, since it is a purchase, and compels them to leave the framework of the gift, which was that of their predecessors, who had clearly perceived the requirement of a counterpart but who made it a countergift. Hugh and Albert must therefore reestablish the framework of exchange and give a monetary interpretation to the expression “without exchange,” which does not mean “without counterpart” but means, on the one hand, “without monetary counterpart” and, on the other hand, more implicitly, “without counterpart of equal value.” The analytical framework is thus prepared for a new stage, on the nature and level of this counterpart. This is what Aquinas does by using the notion of “price,” which had disappeared from the Vulgate and commentaries, in favor of “exchange.”

2.3. Bible and Liturgy: Does Price Really Appear in Celebrating Mass?

To understand Aquinas's introduction of the term “just price” in his commentary on Isaiah 55:1 and the significance of this reference, it is necessary to further investigate the sources that would have allowed him to associate this verse with the term “price.” Among Aquinas's direct sources, after having identified the authorities he used, it is necessary to clarify which versions of Isaiah 55:1 he read in the Bible and in liturgy. The Vulgate, quoted in the margin of the Leonine edition of Aquinas's commentary on Isaiah and which was the reference Bible in the Middle Ages, does not contain any form of “price” in Isaiah 55:1.

However, on the one hand, Aquinas lived successively in Italy, in Paris, in Cologne, and then again in Paris. He therefore encountered a multitude of Bibles, and it is difficult to know whether they were only the Vulgate text, since in the Middle Ages other versions were still in use. The Vetus latina could still be found in the Middle Ages, even though it consisted only of a few biblical books given in this early version within a Bible that otherwise followed the text of the Vulgate (Bogaert 1988: 293–95). The book of Isaiah is not part of this medieval survival of the Vetus latina. Thus, Bible manuscripts identified as at least partially Vetus latina versions give Isaiah 55:1 in the Vulgate version.¹¹ The same applies to medieval Bibles in which other sections of the text are sometimes revised from Hebrew.¹²

On the other hand, in the thirteenth and fourteenth centuries about ten correctoria of the Vulgate appeared, six of them notably in Aquinas's time (Dahan 1992: 179–80). In Paris, a corrected version of the Vulgate appeared (McGuckin 1993: 204). A standard text of the Bible emerged, first with a Correctorium drawn up under the direction of Hugh of Saint-Cher and then an edition of the Bible around 1250 (Dahan 2005: 10). Hugh's Correctorium is the oldest and most widespread. It is probably contemporary with its Concordance, around 1235 (Dahan 2004: 161–62). Three questions remain. First, the discussion about which manuscripts would fall under this Parisian version remains open, which prevents us from ruling definitively on the text that circulated in Paris. Second, Aquinas does not always follow the same text and does not always follow what we know of these texts. Finally, all the work of correcting and editing the Parisian Bible was done at the time of the writing of Super Isaiam, which raises the question of Aquinas's knowledge of this text at the time of writing (Dahan 2005: 12–14).

While it is not possible to rule on the content of Bible versions that Aquinas had, we can simply make two observations.

On the one hand, the Bible de Saint-Jacques, called Omega J (BnF lat. 16721, f. 102rad), edited around 1250, but also the Parisian Bibles Omega M (Paris Maz 5, f. 195vad), edited around 1230, and Omega S (BnF Lat. 15467, f. 340vba), edited around 1270, all keep the Vulgate's version. In addition, the first Correctoire de Saint-Jacques (BnF lat. 3218, f. 152v), edited by Hugh around 1230–35, and the second (BnF lat. 15554 f. 92r), edited around 1260, do not mention any correction for this verse. This confirms Dahan (2005), who does not retain Isaiah 55 in his list of corrections of Isaiah made by the Correctoire and the Bible de Saint-Jacques.

On the other hand, we can look at the version that Hugh retained in his works. In his Commentary on the Book of Isaiah he quotes the verse according to the Vulgate, with the noun commutatio and not pretium (Hugh, In Isaiam, c. 55, p. 130), and in his biblical Concordance Isaiah 55 does not appear for the noun pretium, but it does appear for the noun commutatio (Hugh, Concordantia, pp. 115 and 533). We therefore find no material evidence to suggest that Aquinas had a Bible bearing the term pretium and not commutatio as the Vetus latina does.

Therefore, without affirming it in a definitive way, we can assume, in view of the biblical materials, that the common and perhaps even unique version of Isaiah 55:1 that Aquinas was able to read in the Bible was the Vulgate. We thus need to continue the investigation. Besides the Bible and the Fathers, the liturgy constitutes the third, but perhaps the most important, point of contact of Aquinas with the Scriptures, since it is a place of orality and memorization. Liturgy is an even more interesting source because, having proceeded by successive additions, the biblical versions it uses are not always harmonized, and it retains traces of ancient versions of the Vetus latina (Dahan 1992: 179).

The versions of Isaiah 55:1 Aquinas encountered in the liturgy may be approached through early Dominican liturgy manuscripts. Since Aquinas wrote his Super Isaiam around the time that Humbert of Romans, Master of the Dominican Order, initiated a reform of the Dominican liturgy in the 1250s, three missals surrounding this reform are especially relevant: one that dates from before the reform and two that are typical examples of this reformed liturgy.¹³ It should be noted immediately that all three manuscripts contain the same treatment of Isaiah 55:1: an introit containing an old version of Isaiah 55:1 introducing the term pretium, which means “price” but also “money,” and a reading of Isaiah 54–55 according to the Vulgate. This stability of the liturgical texts from one manuscript to another allows us to assume a certain permanence in the liturgical versions of this verse. It speaks in favor of Aquinas's knowledge of these versions, which may have influenced him.

The introit antiphon for the Saturday after the fourth Sunday in Lent, often called “Sitientes Saturday,” quotes Isaiah 55:1. This Mass’s particular introit originated in antiquity and sets the tone for the celebration, so much so that in Roman lectionaries of ancient times and the early Middle Ages a second reading during the Mass, from Isaiah 55, still echoed it (Schuster 1925: 176; Bernard 1993: 189). This introit appears in early Dominican liturgy in its traditional version. It does not use the Vulgate but another Latin version: “You who are thirsty, come to the waters, said the Lord, you who have no money, come and drink with joy.”¹⁴ In the expression “you who have no money,” the introit uses the term pretium where the Vulgate contained argentum and the Vetus latina (Jerome's Septuagint Latin translation as well as the Vetus italica) contained pecuniam at this place, although, as we have seen, Vetus latina includes pretium in the next part of the verse, which is not included in the introit. We can therefore conclude that Aquinas likely knew, heard, and sang the verse Isaiah 55:1 with the word pretium, although it means money rather than price in this expression.

However, the fourth lesson of the Holy Saturday, being a reading of Isaiah 54–55 (BnF lat. 8884, f. 123rv; SS XIV L 1, f. 0428r; BL Add. ms 23935, f. 535r), does not contain pretium and keeps the Vulgate version. Even without granting too much importance to the parapraxis consisting in repeating “without money” (absque argento) in the manuscript of Santa Sabina (SS XIV L 1), the most famous of the three early Dominican missals studied here—the redundancy is crossed out with a red line—this tends to confirm the spiritual importance of the lexical field of money here. It is striking that within two weeks of each other (from Sitientes Saturday to Holy Saturday), the early Dominican liturgy gives a hearing of two different versions of the same verse from Isaiah, a usage that would continue until the last editions of the Dominican missal in the twentieth century.

The study of the sources thus shows that Aquinas had probably seen the term pretium associated with Isaiah 55:1, at least in the Sitientes Saturday's introit. But in this introit, “non habetis pretium” rather means “you, who have no money” than “you, who do not have price.” The biblical, patristic, and other liturgical sources, however, do not provide any further evidence. In any case, the expression “just price” does not appear in any of the sources consulted. Aquinas thus breaks new ground by associating this notion with Isaiah 55:1.

3. Toward a New Kind of Exchange, Ratio, and Counterpart: Aquinas's Super Isaiam, 55, 1

Aquinas thus makes two major contributions. On the one hand, on the biblical and theological level, probably unintentionally, he does a work of unification of traditions by returning to the broad understanding that was contained in the Hebrew expression. On the other hand, on the level of economic ideas, he innovates, since, probably without copying from his authorities, he associates the notion of price and even more that of just price, that is to say a treatment by the possibility and the level of the price, with what seems at first sight to be a spiritual gift. He does not detail the counterpart in Super Isaiam, but God sets up an affordable counterpart in an available currency. His later comments on the verse of the prophet Isaiah in the mature biblical commentaries In Matthaeum and In Joannem indicate that it is eloquence and study that man must provide in exchange for divine wisdom. Super Isaiam's counterpart is philosophically and economically challenging. God conducts a transaction where the counterpart is below the just price. This would mean that God would sell at an unfair price. On the contrary, justice in Thomasian thought is a divine attribute, and thus the exchange cannot be made at an unfair price. This leads to considering a just counterpart, which is not a price, and which is below what a just price would be if the transaction could have a just price. Aquinas thus not only continues the work of his masters, whom the presence of a counterpart had led to think of Isaiah 55:1 in the context of exchange by restricting the absence of exchange to the absence of monetary exchange and equal counterparts, but in addition he returns implicitly to the tradition of the Septuagint and the Vetus latina: there is indeed exchange with counterpart, but this exchange is done “without money and without price.”

3.1. “Without Price” or “Less Than the Just Price”? The Price at Stake in Super Isaiam, 55, 1

Aquinas's commentary on Isaiah 55:1 deserves attention not only because of the first appearance of the phrase “just price” but also because of the importance of Super Isaiam in his works, which reinforces the value of this protoappearance (see the comprehensive historical file and manuscript study in Oliva 2006: 207–25). Super Isaiam is mentioned in the oldest catalog of Aquinas's works (Leonina 1974: 3*). This early work of Aquinas is, according to a widely shared opinion, “the first theological work of St Thomas” (Leonina 1974: 20*; Bouthillier and Torrell 1990: 6). Although it is a cursory commentary from a young biblical scholar who was just beginning his teaching career, it is already a personal work. Moreover, the work is important because it is one of the few surviving autographs of Aquinas (Super Isaiam, 34–50). This text therefore constitutes a trace of the preparation of his lectures (Gils 1958: 260–62; Bouthillier and Torrell 1990: 5–7; Oliva 2006: 223).

The dating has evolved to bring it progressively forward in Aquinas's career: first seen as dating from Aquinas's first teaching as a master in Paris in 1256–57 (Mandonnet 1928: 34, 116, 130–34) or even as part of his mature writings, it was then seen as the work of the young biblical bachelor at the beginning of his Parisian teaching in 1252–53 (Gils [1958: 260–62], Leonina [1974: 19*–20*], Bouthillier and Torrell [1990: 5], Torrell [1993: 41–42], Oliva [2006: 223], Porro [2015: 5], and Tugwell [1988: 211] date his Parisian teaching on Isaiah a little bit earlier). Super Isaiam may even date from the earlier period, when Aquinas was a biblical bachelor in Cologne (Weisheipl [1983] 1993: 59–60, 404–5, accepted by Bataillon [1980: 119], Leroy [1978: 666], and Émery [1993: 493]). Indeed, Aquinas came to Paris to read the Sentences and not the Bible, and would have been an exception to his Dominican predecessors in Paris. This argues for a slightly earlier writing in 1251–52, in Cologne, where Aquinas was a biblical bachelor of Albert. He would thus have produced this commentary in Cologne under the direction of Albert and in close dependence on Hugh of Saint-Cher (Weisheipl [1983] 1993: 405).

However, there are two arguments supporting the notion that Aquinas wrote Super Isaiam while in Paris. On the one hand, its character as a course preparation, emphasized by Gils (1958) and which Oliva (2006: 223) stresses, has never been questioned. On the other hand, while In Jeremiam and Super Isaiam are roughly contemporary, the former meets the definition of a bachelor's biblical commentary—a quick commentary to make the literal meaning clear—whereas the latter is clearly richer (Bouthillier and Torrell 1990; Torrell 1993: 40–52). Isaiah 55:1 tends to confirm this, notably through the introduction of the concept of price. This would argue for making Super Isaiam a slightly later work dating from Aquinas's arrival in Paris, since it is an early biblical commentary but still his first personal theological work. Without categorically asserting this, and without affecting the analysis of the expression “just price” that it contains, we can therefore retain the hypothesis that Super Isaiam was written in Paris in 1252 (Torrell 2015: 53–54, following Oliva 2006), or possibly in Cologne just before. In any case, the interest of the dating discussion lies in the common assertion of the importance of Super Isaiam as a foundational work in Aquinas's intellectual life, just before the writing of the Commentary on the Sentences.

The commentary on Isaiah 55 begins by identifying the recipients of the divine promise, the servants of the Lord, who are His sons. Then the commentary deals with the promise by commenting on the verse itself. Aquinas employs the concept of price, pretium, twice, in the phrases “without price [or money]” (sine pretio) and “less than the just price” (minus quam justo pretio), whereas the term does not appear in the biblical verse. Each occurrence of pretium introduces a paradox. The first raises a qualitative paradox (buying with no price), the second a quantitative paradox (a just exchange, since it comes from God, but at a level of exchange ratio below the just price):

Aquinas emphasizes the first paradox of the verse by completing the verb “to buy,” which describes an exchange, with an absence of pretium (price or money). Although the biblical, patristic, and liturgical traces that Aquinas might have known of the use of the term in the context of Isaiah 55:1 are very tenuous, he could have memorized the expression sine pretio in Psalms 43:13: “You have sold your people for no price [sine pretio],” which he quotes three chapters before, in Super Isaiam 52, 3. However, he does not quote the end of the verse, although it links price and exchange: “and not much has been earned in the exchanges [in commutationibus] of them” (Psalms 43:13). It could also be the lexicon of commerce, with the verb “to buy,” which leads him here to treat the paradox of the verse by an internal play on the lexicon of exchange: a purchase without a price. Aquinas goes on to specify that the invitation to “eat” concerns bread and other necessities. Then comes the first occurrence of the just price, introducing the second paradox. Aquinas comments on John 7:37 and specifies “in the delights, come, buy, take as if you were buying, even without money, which is less than the just price [idest minus quam justo pretio].” Finally, he specifies the good “which is given free of charge to the thirsty, divine wisdom [divinae sapientiae]” (Super Isaiam, 55, 1).

Aquinas first introduces pretium to emphasize its absence. It probably means “without money,” but it could also mean “no price,” as in Psalms 43:13, although in Isaiah 55:1 it seems more accurate to read “to buy without money” than “to buy without price.” However, the polysemy of pretium leads to the notion of a price absence. Aquinas goes on to refer to price level, which is lower than the just price, because of the absence of money. There is therefore no identity between absence of price and absence of money. He thus accentuates the paradox of the verse: one buys (lexicon of exchange) without a price but takes (outside the lexicon of exchange) at a price, but lower than the just price, and this price comes into play when the transaction is done without money. A too-quick reading could identify the absence of price (sine pretio) at the beginning of the commentary and then the absence of money (absque argento) with the absence of a counterpart and make the operation a simple gift. However, the introduction of the price level would tend to distinguish the exchange/gift dialectic from the money/barter dialectic. Either it is an exchange that tends toward a gift, or it is an exchange that tends toward barter, without money, with a price reduced to the point of not being fair, but with a counterpart, which is not yet specified here, that man would bring in exchange for divine wisdom.

In order to know whether it is a gift or a barter, it is necessary to establish the link between the absence of money and a price lower than the just price. Indeed, the second term, the price, is quantitative; it is expressed according to a level. It is also necessary to know whether the first term, the absence of money, is quantitative or qualitative. If the expression is quantitative, in the sense that the counterpart would be money but that it would be reduced to zero, then in this case the price would tend toward zero. We would then find ourselves in the initial framework of an exchange, but where the seller would lower the price so much that it would be a gift. If the expression is qualitative, it is impossible to exchange with money, but there is another counterpart. In this case, it would be the qualitative criterion of the nature of the counterpart, which would be nonmonetary, that would lead to a quantitative reduction in the price, which would no longer be fair. There are two arguments for the first (quantitative) hypothesis: the fact that the expression “without price” appears earlier in the verse and the fact that there is no counterpart other than money, which is absent. This would suggest that it is a sale that is transformed into a gift. There is an argument for the second (qualitative) hypothesis: it seems to fit better with the idea of price level; otherwise, Aquinas could repeat the expression “without price” here. In order to favor one of the two interpretations, gift or barter, it is necessary to look at Aquinas's use of Isaiah 55:1 in his other works, as well as the way he articulates the possibility of a price and price level.

3.2. The Need for Affordable Price and Available Currency: Isaiah 55:1 in Aquinas's Other Biblical Commentaries

In Aquinas's works, the quotation from Isaiah 55:1 appears only in the scriptural commentaries: in the almost contemporary writings of the early biblical commentaries on the prophets Jeremiah and Isaiah, and then in the mature evangelical commentaries on the Gospel According to Matthew and the Gospel According to John.

In the Commentary on Jeremiah (1252), Aquinas briefly interprets Isaiah 55:1 in the spiritual sense of the teaching, which is like “regenerating waters” (aquae reficientis doctrinae) (In Jeremiam, c. 2, l. 10). He quotes only the first part of the verse, according to the Vulgate, without the final expression “without money and without exchange.” Aquinas therefore does not enter, contrary to what he does in Super Isaiam, into the register of economic metaphor.

Eighteen years later, however, Aquinas takes up the lexicon of the price used in Super Isaiam. The reportatio of the Commentary on the Gospel of Matthew (1269–70), like that on Jeremiah, quotes only the first part of the verse according to the Vulgate. There is therefore no question of price. Nevertheless, he comments as follows: “But how is it sold without money [sine argento venditur]? I say that wisdom is sold without money. And what is its price [quod est pretium eius]? Let a man willingly study [libenter studeat], that is the price of wisdom [pretium sapientiae]” (Super Matthaeum, c. 25, l. 1, no. 2026). The term “price” appears, but it undergoes three shifts. First, it comments on the quotation in the first part of the verse by introducing the second part of the verse, sine argento. In addition, the man pays a price, that of study, whereas in Super Isaiam the gift of God seems free, therefore “less than the just price.” Finally, the commentary no longer introduces a price level or the justice of the price, but deals with what makes the counterpart, “to study,” that allows the payment for a good, “wisdom.”

The Commentary on the Gospel of John (1270–72) contains two mentions of Isaiah 55:1, although they seem less marked by economic metaphor and the lexicon of price is absent. But they echo the Commentary on the Gospel of Matthew in taking up the question of the good and the money with which to buy it. First, in a brief quotation, “All you who are thirsty, come to the waters” (Isaiah 55:1), Aquinas limits himself to a spiritual meditation on water, without mentioning money or price (In Joannem, c. 4, l. 2, no. 577). Later, Aquinas quotes the following verse, Isaiah 55:2, and comments, “‘Why spend your money,’ which is eloquence, ‘not on bread,’ that is, on true wisdom” (“quare appenditis argentum vestrum,” idest eloquentiam, “et non in panibus,” idest, non in vera sapientia) (In Joannem, c. 6, l. 1, no. 849). Here we see that it is a question of paying (a price—the term does not appear but it is implicit), with a counterpart (whereas the verse of Isaiah insists on the absence of money). Here it is “eloquence,” as it is in patristic and medieval commentaries, whereas in Super Matthaeum, c. 25, l. 1, no. 2026, it was “study.” This counterpart is not a monetary one, but it is a kind of currency because Aquinas here uses argentum. It should be noted that Aquinas thus transforms the reference to eloquence into a positive element: it is no longer a question, as in Albert, of those who have no eloquence, but explicitly of those who have it, since they pay with it.

Do the later commentaries mark an evolution in Aquinas's thought in the sense of an inflection: after a first step where Super Isaiam would describe a kind of gift through the expressions “without price” and “without money” and by a level of price that would tend toward zero, later commentaries such as Super Matthaeum and In Joannem present a trade? Or do they rather bring a progressive clarification of the nature of an exchange that would be a barter? Both possibilities remain open, but it is the latter interpretation that seems to be retained. Indeed, the late commentaries seem to harmonize well with Super Isaiam if one retains the reading according to barter. If Super Isaiam introduces the notion of price level, the commentaries of the gospels of John and Matthew introduce the affirmation of its possibility and propose counterparts that allow the payments to be made. These later commentaries thus add the counterpart dimension necessary for the realization of the exchange once the existence of a price has been established.

Combining the commentaries, we can therefore conclude that the economic transaction (at least metaphorically) wherein the notion of “just price” appears, when God sells “without money and without exchange,” has three characteristics. (1) It is below the just price. (2) It still remains an exchange ratio to be paid, the “price” of wisdom. According to the Bible (Vulgate) there is no exchange (commutatio), probably in the restrictive financial sense of trade against money; but according to Aquinas, even if not in a financial sense, there is still an exchange whereby man can get wisdom against another good (study or eloquence), at a certain price—or at least exchange ratio—level. So there is an exchange ratio. (3) The “price” is paid with another counterpart that is not money in a financial sense but study or eloquence. Thus we see that what seemed to be a gift, made “without money and without exchange,” is paradoxically a trade, where we can identify a good exchanged (wisdom), at a price (not a just one), with a currency (study or eloquence). It is a kind of “barter of spiritual goods.” God therefore offers all the possibilities for the trade to take place: a “price” at an unfairly low level in order to be affordable and an accessible and available currency.

3.3. Can God Make an Unjust Trade?

With the expression “less than the just price” Aquinas not only introduces a quantitative paradox, but also a moral one. Can God commit an act, in this case a sale, that is not just? Justice is one of the divine attributes (S. T., Ia, q. 21, a. 1). Sed contra, quoting the psalmist, says “God is just, he loves justice” (Psalms 11:7). Aquinas thus lays down the general principle that God is just. In this case, since it is related to a sale, justice is relative to what Aquinas calls “particular justice,” which consists in commutative and distributive justice. Commutative justice consists in “giving and receiving in return, as in purchases, sales and other communications or exchanges.” This kind of justice “is not suitable [competit] for God” (S. T., Ia, q. 21, a. 1, resp.). Indeed, God cannot be held to commutative justice since he owes nothing, being the first giver. So Aquinas quotes Romans 11:35: “Who gave to him first, that he should be paid in return?” A clarification is needed here. Aquinas is not saying that God contravenes commutative justice, but rather that He is not concerned by it: because in order to have an exchange ratio to pay, He would first have to receive something, whereas He is the origin of everything. God is never in a situation of commutative justice in a real way. However, Isaiah 55:1 is concerned with a metaphorical exchange. Moreover, the situation is reversed with respect to the impediment mentioned by Aquinas, since it is not a question of God having to pay an exchange ratio, but rather of receiving a counterpart for an exchange of which he is the initiator.

The case presented preserves well the postulate that prevented God from meeting commutative justice, namely, that God owes nothing and that everything comes from Him. We can therefore imagine that God meets it, at least metaphorically, since it is a question of a purchase (“buy” [emite]), an activity that enters into the initial enumeration of situations where commutative justice applies. In this case, the general principle applies in the absence of any indication to the contrary: God is just; therefore He respects this commutative justice.

The other kind of particular justice, distributive justice, which consists in distributing (unilaterally, without counterpart) a common good to each person according to his or her merit, “manifests the justice of God” (S. T., Ia, q. 21, a. 1, resp.). At first sight, we could believe that the transaction presented in Super Isaiam, 55, 1 is a matter of distributive justice. On the one hand, it is about God, who according to the beginning of the repondeo is never in a situation of commutative justice, but rather of distributive justice because God owes nothing. In addition, God is like the whole in relation to the part (S. T., IIa IIae, q. 61, a. 1, resp.). On the other hand, we have seen that the Fathers had sometimes read this verse of Isaiah as referring to a unilateral gift without counterpart. Two elements, however, take Super Isaiam, 55, 1 out of the framework of distributive justice and bring it back into that of commutative justice. First, in distributive justice, the ruler, in this case God, “assigns to each one according to his dignity [or merit: dignitatem]” (S. T., Ia, q. 21, a. 1, resp.), but the situation presented does not mention any selection among the recipients, since God invites “all those who are thirsty [omnes sitientes]” (Isaiah 55:1). It must also be noted that even in the case presented by Albert of merit allowing a reward, the transaction is presented as an exchange. Second, Aquinas explicitly introduces a counterpart in his later commentaries on the verse in In Matthaeum and In Joannem.

Religion as a part of justice could be a third way, although it does not appear in S. T., Ia, q. 21, a. 1, resp. about the justice of God because it is not an act of God but of the people. The virtue of religion, which is a distinct part of justice (S. T., IIa IIae, q. 81, a. 4, s. c.), involves a counterpart from the people to God, as in Super Isaiam, 55, 1. However, in this early text the counterpart is not to give back to God what is due because of who God is, but to pay for a good, namely, divine wisdom. The counterpart belongs to the transaction itself. From the buyer's point of view, a distinction must be made between the real and the metaphorical meaning. In the real sense, since he owes God a counterpart, it is an implementation of the virtue of religion, but in the metaphorical sense of the transaction described as a sale, it is an implementation of commutative justice. Looking at the justice of the exchange through the virtue of religion can help to assess the justice of men, but not of God. The issue is about God's justice, since He initiates the sale and charges a price that is not fair.

The metaphorical framework of the sale takes us back to commutative justice. However, this use is metaphorical. It refers to an exchange with a counterpart, but this exchange is not made according to one of the usual properties of commutative justice, namely, the equality between the things exchanged (S. T., IIa IIae, q. 61, a. 2, resp.). This does not seem to present any difficulty since “in commutative justice one considers principally the equality of things [principaliter aequalitas rei]” (S. T., IIa IIae, q. 77, a. 1, ad 3). Through the adverb principaliter, Aquinas allows an extension of commutative justice to particular cases where it is not exercised through this equality ratio.

In any case, whatever the type of justice chosen, there is nothing in Aquinas's works to suggest that God acts contrary to justice. Thus, Aquinas's text deserves special attention. He says “without money, i.e. less than the just price,” but he does not say “at a price lower than the just price,” which would be contrary to justice. It should therefore be considered an exchange ratio that is just and whose level would be lower than what a just price would be.

4. Super Isaiam: The Grounding of Aquinas's Economics-Focused Later Work

Super Isaiam, 55, 1 does not contain any direct development of economic issues. However, the words and the discursiveness of the commentary in this first great work of Aquinas, describing the paradoxical situation presented by the prophet Isaiah, set the foundational intuitions that were to structure his economic thinking henceforth. Three intuitions can be accounted for through three lines. First, Aquinas sets up the notion of “just price.” This just price is higher than the ratio at which the transaction is carried out because the just price does not integrate agents’ resources. Second, the paradox of Super Isaiam's transaction, which is made “without price” but which is a buying operation measured by the yardstick of the “just price,” paves the way for new kinds of transactions, which although falling within the framework of exchange are not truly trading. Third, through this diversity of transactions conceived within an exchange framework, Aquinas introduces different kinds of counterpart. Super Isaiam implements a just exchange ratio, which is below the just price. This counterpart integrates other justice criteria, such as the buyer's limited resources and the currencies available. Diversification of ratios paves the way for a functional distinction between counterparts, and then of incomes.

4.1. Value, Price, and Just Price: Toward a Conceptualization Serving the Justice in Exchange

The framework generated by the references to Isaiah 55:1 in Aquinas's work is that of a barter between divine wisdom, provided by God, and a counterpart, described later as study (In Matthaeum, c. 25, l. 1, no. 2026) or eloquence (In Joannem, c. 6, l. 1, no. 849), provided by people. There remains, however, the issue of the price level, which would transform the barter into a gift if it were equal to zero. Then the two expressions found in Super Isaiam, “without price” and “less than the just price,” would be equivalent, not from a conceptual point of view but from a practical and effective one.

Here, God's will to achieve the sale through any means takes precedence over the justice of the exchange. Transposed into other words, the situation described is as if God had the lowest bargaining power. He does not force the exchange, but He is prepared to do anything, that is, to charge an effective price much lower than the just price that would be consistent with the value of His wisdom to man. The exchange presented describes a scene where the seller knows that the good he is supplying is most useful to the buyer and that its value is very high, but the buyer is not aware of this or could not afford to pay the just price. The seller, who is determined (we would say, according to a French idiomatic expression, à tout prix, at any price) to make the exchange (in this case, to sell his wisdom), keeps lowering the price and facilitating the transaction, even by shifting to a currency more appropriate to the buyer. Presenting such a situation, Super Isaiam can be seen as foundational and innovative. Although the notion of a just price is developed by Albert the Great in his Commentary on the Sentences about the merchants (In IV Sent., d. 16, a. 46), it takes on a new breadth with Aquinas, starting with this first occurrence, and Aquinas was the only one in his time to introduce distinctions between value, price, and other exchange ratios.

Super Isaiam is foundational for Aquinas's further developments on price, notably in the Summa theologiae:

1. Value and price. Although value is not explicitly mentioned either in the biblical verse or in Aquinas's commentary, two dimensions of value are to be found (there was already a plurality of approaches in the works of the Fathers of the Church, as Hengstmengel [2021] has shown). Indeed, the good exchanged, divine wisdom, has both an intrinsic value secundum se, conferred here metaphysically, by its divine origin, and a value or a price derived from its usefulness to those who receive the good. These two approaches to value and price would later be developed in an interlocking manner in his Summa theologiae (Januard 2022d: 744–51). It is both a secundum se value, and a value for the one who holds it: “One may licitly sell something beyond its value secundum se, although it is not sold more than it is worth to the possessor [plus quam valeat habenti]” (S. T., IIa IIae, q. 77, a. 1, resp.).

2. From values to prices: the adjustment process. Aquinas lays the foundations for a conceptual distinction between value and price, since divine wisdom has a metaphysical value secundum se and a just price. This distinction, rarely taken into account in the literature,¹⁶ becomes a structuring feature of Aquinas's works (Januard 2022d: 744–47).¹⁷ In Super Isaiam, just price integrates these needs in a special interaction. From an economist's point of view, the just price is high because of the metaphysical value secundum se of divine wisdom, but also because it takes place in a bilateral exchange in which God would be characterized by an objective function whose argument is the effective advantage drawn by the human being. This advantage is very high, despite the fact that the human being ignores or underestimates the divine wisdom that is to be transferred.

3. The just price's objective content. The sale is not made at the just price, but “less than the just price” (Super Isaiam, 55, 1), that is, below the price which takes into account divine wisdom's value secundum se and the advantage drawn by people. The just price would be so high that man cannot pay it. From an economist's point of view, the seller (God) voluntarily agrees to grant a discount that is not in line with the just price but is in line with the resources of the buyer. Otherwise, the transaction cannot take place. In considering such a just ratio not to be a just price, Aquinas provides an element that is taken up implicitly in his later writings: the purchasing power of the buyer does not enter into the determination of the just price. This sheds light on both his treatment of the just price in commercial exchange (e.g., S. T., IIa IIae, q. 77) and of usury (e.g., S. T., IIa IIae, q. 78). Aquinas does not rely on the resources of the agents but only on the good to settle the justice of the exchange. For instance, concerning usury, he keeps a certain distance from the traditional argument of the Fathers, namely, the “conditioned will,” where lending would always consist in the enslavement of the poor by the rich. He does not seek to show that interest is unfair because it is too high for the resources of borrowers, but because of the very good exchanged. Aquinas thus draws a major outline of his later writings as early as Super Isaiam. In order to establish the justice of exchange, he bypasses the lack of information about the agents (their intention, but also their resources) to look for visible and objective criteria of justice related to the nature of the good exchanged (Januard 2023: 664–76).

This objective approach leads to a clarification of posterior developments about the just price. In Super Isaiam, price does not come from the individual fancy of the agents but from some objective advantages that God knows and that people sometimes admit. It is not denied that people can subjectively feel it, although it is external to them and objectively given. In this early work, Aquinas thus laid the foundations for further developments on utility in his later works (Lapidus 1994: 440). Nonetheless, this objective dimension of the just price is only shown implicitly: the transaction has to take place, and to do so other criteria must be taken into account, such as the agent's resources. God adjusts the amount of the exchange ratio to allow people to benefit from His wisdom even if they cannot afford it.

The approach already present in Super Isaiam, 55, 1 shows that the quest underlying Aquinas's study of economic issues is already at work in this early writing. The search for visible indicators of the justice of exchange that reduce the lack of information about the subjective dimension of this exchange, such as the intention, the resources, or the perceptions of the agents, finds in Super Isaiam an already extended exposition, not by explanations, which are absent, but by the situation presented.

4.2. A Third Way between Gift and Trade: A New Kind of Exchange and a New Role for Price

After considering value and price, it is appropriate to consider the nature of the transaction, because Super Isaiam, 55, 1 describes a transaction that is somewhat strange. Indeed, it remains to articulate the two dimensions of the price: its absence and its level. The kind of “presence-absence” of a price is ambiguous, but it helps to distinguish the issue of the possibility of an effective price and the concept of price and just price. First, Aquinas comments upon “buy” with sine pretio. Second, the Vulgate contains “without exchange” (absque ulla commutatione) and not “without price” (absque pretio) like the Vetus latina (Isaiah 55:1). However, the concept of price is more likely to appear afterward. The just price is present and has a level: the Bible describes a transaction where people are invited to “buy” (Isaiah, 55:1), which implies counterpart, and Aquinas comments on “without money” (absque argento) with “less than the just price” (minus quam justo pretio) (Super Isaiam, 55, 1), introducing a quantity criterion on price. Later works such as In Matthaeum and In Joannem confirm this quantified counterpart, namely, study or eloquence. However, although the just price is conceptually present, the effective price is absent since if it were present it would be lower than the just price and the transaction would be unfair.

This double dimension highlights the importance of Super Isaiam in three ways. First, it shows that Aquinas, from his first great biblical and theological work, and on a subject that is spiritual and where exchange is taken only in a metaphorical mode, has recourse to the concept of price and just price through the dialectic between possibility and price level.

Second, Super Isaiam is a founding work and a harbinger of future developments in Aquinas's thought, when he deals with goods that cannot be traded, and where the price is first expressed in terms of impossibility, before being expressed in terms of an unattainable level. This will be the case for the second occurrence of the expression “just price,” which appears in the Commentary on the Sentences, an early work that follows Super Isaiam, when it deals with simony, the sale of spiritual goods, which is forbidden (In IV Sent., d. 25, q. 3, a. 1, qc. 1). Here Aquinas distinguishes between the justice of exchange according to quantity (in quantum) and according to the nature of the good (in quid), which may make it priceless. Fifteen years later, in the Summa theologiae, this impossibility will no longer be expressed only in qualitative terms but sometimes in quantitative terms, with the idea that the effective price would always be much lower than the just price for such a fine good: “This would be selling a great thing for a very low price” (S. T., IIa IIae, q. 100, a. 3, ad 2). We see the same quantitative expression about the free man: “The person of a free man surpasses all pecuniary estimation” (S. T., IIa IIae, q. 189, a. 6, ad 3). The just price is possible but unattainable (Januard 2022a: 584; Januard and Lapidus 2023: 128–29).

Finally, it testifies to the nature of the good, which is at first without price before in the later works being exchanged for under the just price. The evolution in Aquinas's work concerns nontradable goods, which cannot be sold, and particularly spiritual goods, to which the divine wisdom referred to in Super Isaiam, 55, 1 can be related. While the rhetorical expression evolves to adopt market terms and the lexicon of the price level, it only continues to describe the ontological impossibility of selling spiritual goods. Here, then, would seem to be an argument for the absolute gratuity of divine wisdom and the definitive affirmation of the framework of the gift. However, in the cases of simony or the free man, it is on the one hand the disproportionality that is asserted, as no just price can ever be effectively paid. And on the other hand, there is nothing to prevent a contribution in the form of an offering (In IV Sent., d. 25, q. 3, a. 2, qc. 1, ad 4; S. T., IIa IIae q. 100, a. 2, resp.).

The second occurrence of “just price” (In IV Sent., d. 25, q. 3, a. 1, qc. 1) thus sheds light on the first (Super Isaiam, 55, 1). The transaction is not strictly speaking a barter in the sense of a nonmonetary commercial exchange, since the exchange is not made according to an equality of exchanged goods, an aequalitas rei (S. T., IIa IIae, q. 77, a. 1, ad 3) through a price, but simply by the payment of an offering which is here study or eloquence. In this sense, the two expressions found in Super Isaiam can be unified, since it is indeed an exchange “without price” but at the same time with a payment evaluated quantitatively but that is “less than the just price.” It is not strictly speaking a gift either, since a counterpart is expected, and although the fact that God's priority is to impart divine wisdom means that the counterpart may tend toward zero, the framework is still that of an exchange ratio.

4.3. An Exchange Ratio Which Is Not a Price: Toward a Functional Distinction between Incomes

Recent literature has highlighted the articulation of gift and exchange, and sometimes their interweaving, through adopting an anthropological approach.¹⁸Super Isaiam, 55, 1 suggests a complementary path, which is more objective and focused on the transaction rather than on the agents. It paves the way for a functional distinction between incomes within the exchange itself, that is, in a framework that is not that of the gift: Aquinas proposes a model of a transaction that is not a gift but whose exchange ratio is less than the just price. This ratio would therefore be unjust if it were a price, but it is not unjust in its own kind (God's action is fair). This early writing thus introduces an income that is thought of as a compensation, not as a price.¹⁹ The situation found in Super Isaiam, 55, 1, where a just ratio takes into account the agents’ resources and their purchasing power (but if it were a price, it would be unjust), is not found any more in later works. Indeed, in these works, ratio variations linked to personal situations of the agents are price variations. They derive from needs and not from resources, and fall under a situation of just price (see, e.g., the case of the buyer who voluntarily pays more out of honesty because of his high need in S. T., IIa IIae, q. 77, a. 1, resp., or the evocation of useful friendship in S. T., IIa IIae, q. 77, a. 1, ad 3). In a purchase and sale transaction, there is no case of a fair exchange ratio that is anything other than a price.

However, the functional distinction between incomes suggested in Super Isaiam, 55, 1 gives an as-yet-unexploited key to understanding many situations. The first one is the remuneration of the lawyer (advocatus), which, like that of the doctor (medicus), must be moderate and is not based solely on the equality of things, but is done “taking into account the personal condition [of their clients: considerata conditione personarum], the cases [handled: negotiorum], the work [laboris], and the customs of the country [consuetudine patriae]” (S. T., IIae IIae, q. 71, a. 4, resp.). Here, as in Super Isaiam, the fair exchange ratio takes into account the resources of the buyer and is therefore not a price.

This specific focus on lawyers’ remuneration had already been present in Roman law since the Roman mid-Republic (Melkevik 2019: 105–7). The Lex cincia de donis et muneribus (204 BC), which underwent a series of nonapplications and reinstatements until the beginning of our era, was intended to be very strict. By prohibiting gifts, this law meant in practice that lawyers were not allowed to receive any remuneration. There are two reasons why lawyers are not paid: corruption, but also enrichment, as lawyers would make false accusations in order to enrich themselves. Aquinas's argument seems a bit different. Vigilance in the face of the abuses committed by the profession may lead him to insist on the need for moderation of income. However, the association with the doctor and his reference to the personal situation of the clients focus attention on the need for services as indispensable as those of a doctor or lawyer to be accessible to all. Certain goods and services can therefore only be exchanged if the buyer's financial capacity is taken into account in the exchange ratio, whereas the price is an exchange ratio based on an equality of values, with no personal considerations for the situation of the agents.

Other cases are loan interest, merchant's income, and the Mass offering given to the priest. First, the loan cannot involve interest, because the compensation (recompensatio), or the amount of the sale of money, is the equal sum returned (S. T., IIa IIae, q. 78, a. 1, ad 5 and a. 2, ad 4). It is a quantified counterpart, but the word used is not “price.” Moreover, the loan can give rise to another kind of compensation: a gracious gift (gratium donum) or a nonfinancial compensation such as benevolence and love (S T., IIa IIae, q. 78, a. 2, resp. and ad 1). Even more, Aquinas gradually admits extrinsic titles in S. T., IIa IIae, q. 78, a. 2, ad 1 by stipulating compensation for the damage caused by the deprivation of the sum (damnum emergens), that is, the opportunity cost (but excluding lucrum cessans, loss of profit) and in De malo, q. 13, a. 4, ad 14, where Aquinas opens the way to poena conventionalis, a penalty for late repayment. The literature so far has done little to emphasize that Aquinas did not use the term “price” to describe these compensations and did not present them as necessarily being of equal value. But Aquinas does not present it as an equal-value counterpart.²⁰

Super Isaiam, 55, 1 suggests moving away from the binary approach of distinguishing between transactions that have an exchange ratio (which would necessarily be a price) and those that do not. This early text leads us to consider a multitude of possible ratios. Indeed, if any ratio were a price, the price of the loan being the sum lent, any additional counterpart (gift, benevolence) would be integrated into the price and would make it unjust. In addition, extrinsic titles are exchange ratios, but not prices. S. T., IIa IIae, q. 78, a. 2, ad 1, setting damnum emergens, stipulates a compensation (recompensatio) for prejudice (damnum), but it is not a price. De malo, q. 13, a. 4, ad 14, setting poena conventionalis, considers that in this case the borrower “is bound to an interest” (tenetur ad interesse). The verb intersum (to be between) appears in the Roman law (Digestum, XVII, 2, 60), and the noun interesse is used by canonists in the Middle Ages (McLaughlin 1939: 141; Blaise [1975: 499] gives Aquinas's De malo as the key reference) to indicate that the time gap has to be compensated (in contrast to the later meaning of the term “interest,” this refers to the delay in payment, not to the interval between the loan and its due date). Aquinas uses this specific noun, and by doing so he sets up a new kind of counterpart. Moreover, he contributes to laying the foundations for a future characterization of loan's income (the interest it earns), since the term interesse will be retained, but with a shift in meaning, as the name of this income.

Second, the functional distinction between incomes is also used in another context. Aquinas distinguishes between a stipend or allowance (stipendium) and wages (praemium), thought of as “the price of work” (pretium laboris) (De veritate, q. 26, a. 6, obj. 10). Stipendium is not a price that would be a counterpart of equal value (Januard 2022c: 86–90). It is the soldier's income (In IV Sent., d. 16, q. 4, a. 2, qc. 3, resp.). Aquinas takes up this notion of compensation in the Summa theologiae to characterize the merchant's income as a quasi stipendium laboris, “like a stipend for the work” (S. T., IIa IIae, q. 77, a. 4, resp.). It is the same term that designates a witness's allowance in a court case (S. T., IIa IIae q. 71, a. 4, ad 3) and the tribute due to the king (Ad Romanos, c. 13, l. 1, 1041). Although it rewards an effort (Koehler 2020: 362), it is a social compensation that allows the beneficiary to provide a service, but this compensation is not of a value equal to the work provided.

Third, Aquinas specifies the priest's income according to the prohibition of the sale of spiritual goods (simony). The priest cannot receive an income coming from a price: neither “the price of a wage” (pretium mercedis) (S. T., IIa IIae q. 100, a. 2, resp.) nor the price of the sacrament that he celebrates, “the price of the Mass” (pretium missae) (In IV Sent., d. 25, q. 3, a. 2, qc. 1, ad 4). Nevertheless, he can receive a “kind of means of subsistence” (quasi sustentamentum vitae) (In IV Sent., d. 25, q. 3, a. 2, qc. 1, ad 4) or a “tribute paid to necessity” (stipendium necessitatis) (S. T., IIa IIae q. 100, a. 2, resp.). This, therefore, seems more like a subsistence allowance, allowing him, as is the case for the soldier or the merchant, to be available to carry out his mission.

Super Isaiam thus already bears the seeds of a functional distinction between incomes, not yet between income from capital and income from work, but between wages and compensation. This distinction between incomes is part of the justice of the transaction, because before establishing the fairness of the amount of the transaction, it is necessary to establish its nature. Thus, in Super Isaiam, 55, 1, the transaction made by God is just. The counterpart corresponds to an unjust price level, but the just nature of this counterpart is not a price; it is a compensation, whose level is just. The nature and level of the compensation are therefore just. Conversely, if a just price were applied, the transaction would not be just, because the nature of the counterpart would be unjust.

This approach, based on the nature of the income, once again makes it possible to reduce the risk arising from the lack of information about the agent (Januard 2024), whose virtue and charitable intention remain hidden, in order to stick to the objective and visible nature of the transaction and to base the justice of the exchange on the justice of the nature of the counterpart, then on its level.

5. Conclusion

In Super Isaiam, 55, 1, Aquinas takes an epistemological step in economics. Theology provided him with an opportunity to deepen his understanding of economic mechanisms. Aquinas introduces the expression “just price” for the first time in a text dealing with the relationship between man and God, and by using this metaphorical expression he establishes a properly economic framework for analysis that will be used in subsequent works to account for situations involving the exchange of goods and services. Our aim is not to make a normative, religious, or moral reading of this metaphorical use, in terms of how economic activities should be guided, but to make a properly positive reading of it: to understand what this use contributes to Aquinas's understanding, and to that of economists today, of what an exchange ratio is and of the different modes of exchange.

While theologians and philologists have been able to see in Super Isaiam Aquinas's first theological work, it is also possible to recognize in it his first work of economic significance. The first reason is lexical, with the appearance of the expression “just price,” which would later constitute one of the characteristic markers of the Thomasian analysis. It is a metaphorical description of the spiritual relationship between God and man. Aquinas takes up more explicitly the reading in terms of reciprocity initiated by Hugh and Albert and strengthens it by introducing the notion of price. God gives His grace, but man is obliged to give in turn what he can. Whereas the use of “price” is metaphorical, the meaning is strictly economic.

In addition, this use is innovative. The term pretium does not seem to be very prominent in the sources available to Aquinas, either in the Latin versions of the verse or in the commentaries. It is found in a liturgical version of the verse in Isaiah, but probably more in the sense of “money” than in the sense of “price.” Furthermore, the introduction of the expression “just price” is a Thomasian innovation. Here again, although innovative, the expression could be incidental. But the reading of Aquinas's text shows, on the contrary, that it introduces not only the concept of just price, to which Aquinas has recourse in his later works to consider the justice of exchange, but also contains a reflection on the notion of counterpart that opens up a first functional distinction between incomes. Indeed, God commits no unjust acts, so He cannot charge a price that is not the just price: however, the exchange does take place here under the just price. We must therefore deduce that the exchange ratio is not a price, which would be unjust, but is of another nature.

Aquinas thus introduces a distinction between a price and a compensation, which would be very useful to him later, in the Commentary on the Sentences, the Summa theologiae, and De malo, when considering exchanges, which are gifts and for which there is a counterpart, but which concern goods or services that cannot be the subject of a price. This is the case of the priest (to sell spiritual goods such as the sacraments is a sin of simony, but the priest needs to be given means of subsistence), of the soldier (who receives a stipendium, stipend or allowance), and also of the merchant (who can receive a quasi stipendium, a kind of allowance), or of the lender who suffers damage because of the deprivation of the sum lent (and who can receive a recompensatio, a compensation for the damage) or who is reimbursed with delay (who can receive an interesse, a specific time-related compensation). They receive compensation for the social service they provide, but it is not a salary that would be the price corresponding to the value of this service.

In Super Isaiam, 55, 1, the reason why compensation is not a price is different. God wants the exchange to take place, but man could not pay the just price for the grace given by God. The just exchange ratio differs from the just price because it takes into account the resources of the buyer. In the case of the priest, the soldier, the merchant, or the moneylender, it is more a question of not getting rich by being paid according to the value of one's activity, but simply compensating him for being able to exercise it. However, in his early work, through a metaphorical situation, Aquinas introduces into his analytical apparatus a plurality of possible exchange ratios and counterparts according to the nature of the activity and the agents. This allows him to specify what is contained in the price and what would belong to another exchange ratio, and to think of a multitude of limit cases within the framework of exchange. It also adds a first step to the justice of exchange. Emphasis has often been placed on the notion of a just price: but before checking that the level of the exchange ratio is just, it is necessary to choose the right exchange ratio. This is important today when dealing with specific goods whose exchange is not, or is not purely, commodity-based.

The author would like to warmly thank André Lapidus, Nathalie Sigot, Nadeera Rajapakse, Timothy Bellamah, and Benedict Young, as well as the two anonymous referees, for their helpful remarks and suggestions. Responsibility for the opinions expressed in this article lies entirely with the author.

Notes

References