The Difficulty and Seriousness of the Danger: An Initial Approach to Frequency and Maximum Loss

Albert and Thomas, like Peter Lombard, deal conjointly with the activities of soldiers, publicans, and merchants (Januard Reference Januard2022b). While Thomas deals mainly with soldiers and merchants, Albert deals more with publicans and merchants. Thomas’s article is much shorter than Albert’s, containing only two objections, a brief sed contra, and a reply, which implicitly endorses the objections without mentioning them and does not even reply to the objections. Albert’s article, on the other hand, contains three general objections, five objections specific to commerce, two specific to publicans, two sed contra, and a long reply.

For Albert and Thomas, the economic justification for trade is the need for supplies. Albert devotes to this necessity two objections that are specific to trade, one considering that “trade is useful throughout the earth [negotiationes utiles sunt toti terrae]” (AM, In IV Sent., d. 16, a. 46, q. 1, obj. 3), the other expressing that without it “the social life of the city is dissolved [dissolvitur civilitas]” and with it is “conserved at its best [optime conservatur]” (obj. 4). Thomas again takes up the necessity of supply with similar formulations in the first objection, although he limits the exchange to necessary things and to the supply of the people of the city, where Albert saw its usefulness for the whole earth: “The city [respublica] cannot be conserved [non potest conservari …] without trade [sine negotiatione], by which the necessary things [necessaria] are procured for the people” (TA, In IV Sent., d. 16, q. 4, a. 2, qc. 3, obj. 1).

It is still necessary for both authors to establish the licitness of trade theologically, by showing that there is no contradiction with Scripture. Albert addresses this question in his first two general objections, in which, relying on Luke 3:14, he stresses that John the Baptist does not forbid soldiers to exercise their profession but that they must be content with their stipend. In the first two objections specific to merchants, Albert then relies on the examples given in Genesis 49:13 and Proverbs 31:14, which mention, albeit in a very allusive way, merchant activity without condemning it. In his second objection, Thomas takes up Albert’s first argument. He says nothing about merchants, but John the Baptist, who taught penance, did not forbid men to be soldiers (Thomas refers to Matthew 3, but the point is made more explicitly in Luke 13:13) or publicans to perform their office (Luke 3:14). There is therefore no significant difference between Albert and Thomas on this question of non-condemnation by Scripture. Thomas summarizes the argument in a more concise text, limits himself to the Gospel, and deals only with soldiers, ignoring the case of merchants. The tacit licitness contained in his respondeo shows, however, that he equates soldiers and merchants in a way that does not contradict Scripture.

Albert preserves this concern for a theological foundation for the licitness of trade in his two sed contra, one biblical, the other patristic, which provide the general line of the article. In his first sed contra, he starts by quoting the Bible’s book of Ecclesiasticus in the common Latin Vulgate version, which indicates, “It is difficult for traders to avoid negligence and the tavernkeeper will not be justified for his sins of lips [Difficile exuitur negotians a negligentia, et non justificabitur caupo a peccatis labiorum]” (Ecclesiasticus 26:28).

He comments by considering that “[h]e who trades [negotiatur] places himself in the critical danger of having difficulty escaping from sin [commmittit se discrimini difficulter evadendi peccatum]” (AM, In IV Sent., d. 16, a. 46, a. 1, s. c.).

He concludes that “no one should put himself in danger [discrimini], therefore no one should trade [negotiari].” Sin appears here as a risk, a highly probable possibility, but not as a systematic situation. The term discrimen, which means the critical point of danger, was taken up by Thomas in the economic section of his political treatise De regno, II, 7 (II, 3): “diversa viarum discrimina [various dangers of the ways]” to describe supply difficulties.

Trade is therefore difficult to conduct fairly, and the lexicon of difficulty appears twice, with difficile and difficulter. This puts the merchant in danger (discrimen). The two terms here, difficulty and danger, evoke the seriousness of the situation, both in terms of probability and in terms of maximum risk. The notion of difficulty (difficile, difficulter) suggests that the sinful situation arises very often, and the term discrimen, which is stronger than the term periculum, usually used to describe danger, evokes the serious peril incurred by the merchant, and hence that we are in a theological context and that his eternal salvation is at stake.

If we consider, in contemporary terms, risk as a random variable running from states of the world to a set of possible consequences, Albert’s association of discrimen with the difficultas contained in the quotation is of major interest, since it distinguishes and states the two aspects of risk: frequency and amplitude.

It should be noted, however, that Albert no longer comments on what he himself states in the sed contra about the merchant’s duty to abstain from this dangerous situation (discrimen). This is a practical danger that the merchant must guard against, but it does not make the activity illegal. We therefore see the emergence of a primary lexicon of risk, difficultas, which indicates frequency, and a secondary one, discrimen, which indicates the intensity of the danger. The sed contra considers that the maximum loss is very high, as indicated by the use of discriminen and simply periculum, which justifies theologically in a subjective way that nobody should trade, but Albert adopts an objective reading of the nature of the activity of his own sed contra. Whatever the maximum loss incurred, namely damnation, this loss is the same as for other activities, but like other activities, trading can be practiced without sin. The issue of the difference between difficulty and impossibility therefore takes precedence over the assessment of the maximum loss, not because in the analysis of risk frequency would take precedence over loss but because, more fundamentally, the notion of frequency places the activity in the category of risk. Thus, in his respondeo, he limits himself to setting out the three conditions for practicing the profession (Januard Reference Januard2022b): persona (person), tempus (time), modus (mode). Priests and monks are forbidden to engage in this activity; it is forbidden on feast days or days of speculative risk, when it would lead to caristia, which in medieval Latin means both a situation of high cost of living and a situation of scarcity (Blaise Reference Blaise1975, p. 149), as at harvest time, and must not be carried out under a vitiated contract (vicius contractus), which would involve deception (deceptio) or price fraud (fraus pretii).

Rarity and Practical Absence: On the Edge of Possibility?

The second sed contra refers to Gregory. Albert starts from a quotation that evokes the fact that in the Gospel Matthew cannot become a tax collector again after his conversion, but the quotation speaks of business (negotia). Albert repeats, or probably thinks he is repeating, the quotation given by Peter Lombard in his Sentences written around 1150 (IV Sent., d. 16, c. 3). Peter Lombard quoted Gregory VII, who considered in 1078 that the soldier and the merchant “cannot practice without sin [sine peccato exerceri non possint]” (Gregory VII, Concilium Romanum V, col. 801b–c). This text of Gregory VII had already been taken up by Gratian ten years earlier in 1140 (Decretum, II, causa 33, q. 3 De poenitentia, d. 5, c. 6). The activity of merchants would always be marked by sin and they could not therefore practice sincere penance without renouncing their activity. This is at least how Peter Lombard sees it, and how Gratian summarizes it in the title of the quotation from Gregory VII: “it is not permitted to return to trading after conversion, for it cannot be done without sin” (Gratian, Decretum, II, causa 33, q. 3 De poenitentia, d. 5, c. 6). This position is in line with the common perception among the Church Fathers of trade as a sinful activity (O’Brien [1920] Reference O’Brien2001, pp. 79–80; Koehler Reference Koehler2020, p. 362), although Augustine of Hippo seems to be much more open (Enarrationes in Psalmos, LXX, §17; Baldwin Reference Baldwin1959, p. 15).

However, Albert makes a transformation, since he does not quote the same phrase from Gregory. In fact, there seems to be some confusion about the identity of Gregory, since Albert quotes a homily on St. John by Gregory I (540–604), known as Gregory the Great (Hom. 24, §1540, col. 1184c), and not the sentence by Gregory VII quoted by his predecessors: “There are many occupations [negotia] that can scarcely or not at all [vix aut nullatenus] be carried out without sin; therefore, those that involve some sin, it is necessary that after conversion, the soul does not return to them” (AM, In IV Sent., d. 16, a. 46, q. 2, s. c.).

However, the turn of phrase in Albert’s reply seems to echo the words of Gratian and Peter Lombard. As the texts contain only the name Gregorius, it is likely that this is a case of confusion.

The confusion between Gregory VII, who evokes the impossibility of practicing commerce without sinning, and Gregory the Great, who evokes only the rarity or practical absence of the situation, does not appear to have been noted by commentators so far. However, this is vital to understand the transformation achieved by Albert and then Thomas. It allows Albert here again to step into the breach by holding that difficulty is not impossibility. The whole argument of the article is thus based on the difficulty of not sinning, but this difficulty cannot justify concluding that trade is illegal.

The expression “vix aut nullatenus [scarcely or not at all]” refers to the rarity and difficulty (vix) of the occurrence, which may tend towards zero (nullatenus). However, the term nullatenus does not mean an impossibility but a simple empirical absence. It is the result of observation and not of demonstrative certainty. The term comes late and is built on quatenus, which means “up to the point where” in the literal and figurative sense, itself built on “held” or “up to,” with the nuance “no further than” (Ernout and Meillet Reference Ernout and Meillet2001, pp. 450, 552, 685). Thus, nullatenus indicates a direction. Albert’s expression then means “scarcely or to the point where not at all” and refers to a situation that, in contemporary terms, could be considered to have a low or near-zero probability of occurring.

A similar formulation can already be found in Gratian’s Decree. Alongside the passage already mentioned, where he quotes Gregory VII, Gratian deals with merchants in his decree Ejiciens (more precisely, it is a palea, a text added between 1145 and 1160): “A man [who is] a merchant can scarcely or never please God [homo mercator vix aut numquam potest Deo placere]” (Gratian, Decretum, I, causa 88, c. 11, Ejiciens). However, Gratian does not mention Gregory the Great. It is therefore possible that Albert may or may not have deliberately merged Gratian’s two passages, or the passage taken up by Peter Lombard that quotes Gregory VII, and the Ejiciens decree, attributing to another Gregory a quotation that comes from a text other than the one in which Gregory VII is quoted. What is more, it should also be noted that numquam expresses impossibility more than nullatenus, and not just a rarity that tends towards practical absence or zero probability. The lexical shift from numquam to nullatenus reinforces the affirmation of a lexicon of probability initiated by the notion of rarity (vix).

Albert thus proposes a double lexicon: a primary one, that of rarity (vix), and a secondary one, indicating the limit case of this rarity (nullatenus). The aim is no longer, as in the first sed contra, to describe the two dimensions of risk (frequency and intensity) but to describe frequency and its limit. The term nullatenus constitutes an inner boundary of risk, whereas non potere evokes an outer boundary, which is foreign to it, since impossibility evokes the absence of risk.

A superficial reading might be limited to what appears to be a simple nuance of expression between the two popes called Gregory. A more suspicious reading might see the change in quotation as a clever device on Albert’s part to legitimize the trade. In reality, the quotations from Gregory VII and Gregory the Great reflect, in the medieval conception, the expression of two radically different situations. Gregory VII’s expression non possint literally translates an impossibility, i.e., a certainty, whereas vix aut nullatenus evokes an absence of certainty, i.e., what is contingent. In the Aristotelian perspective taken up by Thomas, a clear distinction is made between what is necessary, what is possible or contingent, and what is impossible, and the contingent is not presented as a degree towards one or the other of the other two terms (TA, Peryermeneias, I, 13–15, pp. 65–82).

We find a somewhat similar situation in terms of the order of knowledge. Although the probable is what is held to be true (Schuessler Reference Schuessler2019, pp. 22–59), there are two different orders of knowledge. The first one belongs to opinion and argumentation; the other belongs to science and demonstration (Aristotle, Rhetoric, II, 1402b20–21; see also I, 1357a24–35; TA, In Post., I, 1, p. 5, l. 69–71). Thomas writes almost five centuries before the expression of probability that derives from the calculus of probability as a “degree of certainty [gradus certitudinis]” by Jacob Bernoulli in 1713 in his Ars conjectandi, IV, 1, p. 211; and IV, 4, p. 225 (Byrne Reference Byrne1968; Daston Reference Daston1988; Hacking Reference Hacking2006). It leads to distinguishing the certain and the probable. However, the word certainty (certitudo) may sometimes refer to probable certainty (certitudo probabilis), which is not an absolute certainty. In fact, the expression is rarely used by Thomas, but it occurs in TA, S. T., IIa IIae, q. 70, a. 2, resp. The “probable” is opposed to demonstrative certainty (certitudo demonstrativa), which is proved by science. This is one reason why—among others—when Thomas writes that the argument against usury, according to which a monetary loan is a mutuum, an interest-free loan derived from Roman law, is satis probabilis (quite probable) in TA, In III Sent., d. 37, a. 6, resp., he may be expressing his doubts because it means it cannot be demonstrated to be certain (Januard Reference Januard2021, pp. 611–617; Januard Reference Januard2024, pp. 425–430; Januard Reference Januard2025, pp. 12–13, 31–32).

The distinction between the necessary and the probable then explains the difference in moral position between Gratian and Peter Lombard on the one hand, and Albert and Thomas on the other. It is not a question of a different assessment of the probability of sinning but of a different classification of the activity. For the former, it is an activity that leads to sin by necessity; for the latter, it is an activity that, like all human activities, can lead to sin but also meets certain interests, in this case supply. The practical fact that few, if any, merchants can be found who do not sin does not change the classification of the activity.

The end of the article, in which Albert finds himself caught up in the confusion over the two Gregorys and visibly thinks he is correcting the version his predecessors give of Gregory VII, whereas he relies on Gregory the Great, clarifies the distinction between the two conceptions of trade: “It must be stated that [Gregory] himself does not say that they cannot [non possint] be practiced without sin, but rather that scarcely or not at all [sed vix aut nullatenus] … it is difficult (difficile) for them not to exceed what is due in their demands” (AM, In IV Sent., d. 16, a. 46, ad obj.).

Albert unifies the two expressions of the risk of sin, the lexicon of difficulty (difficile), which came from the first sed contra, and that of scarcity and practical absence (vix aut nullatenus), which came from the second. He contrasts these expressions with the expression of impossibility (non possint). This synthesis is of interest not only for understanding trade but also for establishing the analytical framework for understanding all economic activity. Indeed, Albert establishes the assimilation of commerce to the usual activities of human beings, and hence its licitness subject to certain precautions, which he then sets out through his three conditions persona, tempus, modus. But more than that, Albert introduces the notion of risk in economic activity through two main lexical fields, to which he adds two related fields: that of difficulty (difficultas), to which he adds that of danger (discrimen), which enables him to consider risk both in terms of frequency and maximum loss; and that of rarity (vix), to which he adds that of the tendency towards practical absence (nullatenus), which enables him to assert, in contrast to the expression of impossibility (non potere) of his predecessors, a new approach to the activity.

Thomas or the Introduction of the Lexicon of Frequency

Thomas takes up Albert’s thesis but with some differences. The quotation from Ecclesiasticus 26:28 is absent from TA, In IV Sent., d. 16, q. 4, a. 2, qc. 3. The second part of the verse, without the expression of the difficulty, will only appear in TA, S. T., IIa IIae, q. 77, a. 4, ad 3, at the end of the question of the Summa theologiae on commercial fraud.

In the Commentary on the Sentences, however, Thomas refers to Gregory, as do Gratian, Peter Lombard, and Albert, again with, no doubt, a confusion between Gregory VII and Gregory the Great. The position of Gratian and Peter Lombard and their quotation of Gregory VII seem to be mixed up with Albert’s position with the quotation of Gregory the Great. His sed contra, which responds to objections in favor of trade, is terse: “Gregory says the opposite in his writings” (TA, In IV Sent., d. 16, q. 4, a. 2, qc. 3, s. c.), which can apply to both Gregorys (Gregory VII and Gregory the Great) but seems more clearly in line with Gratian’s and Peter Lombard’s quotation of Gregory VII than with the homily on the Gospel of John by Gregory the Great quoted by Albert. However, Thomas’s response is, like Albert’s, open to trade. Thomas uses Albert’s criteria persona, tempus, modus simply to provide a framework for trade.

Thomas mentions Gregory only at the end of his respondeo, referring to the tax collectors, which is more in line with the quotation from Gregory the Great. He proceeds in the same way as Albert, with a concluding sentence that gives a liberal interpretation of Gregory after setting out the conditions of licitness for trade: “What Gregory says in his letter must not be understood as meaning that it is not possible without sinning, but that it frequently leads to sinning [frequenter ad peccatum implicat]” (TA, In IV Sent., d. 16, q. 4, a. 2, qc. 3, resp.).

The distance taken, exceptionally in Thomas, between the sed contra and its evocation in the response seems to attest a form of embarrassment that is not found in Albert. It is possible that he did not realize that they were two different quotations and that he was trying to put the quotations together and apply Albert’s position (difficulty is not impossibility) to his own sed contra in his respondeo, which was the statement by Gregory VII that he had read in Gratian and Peter Lombard.

Thomas does not use the vocabulary of difficulty, which is logical since he does not refer to Ecclesiaticus 26:28 in his article in the Commentary on the Sentences. He interprets Gregory’s expression obviously with Albert’s text in mind, i.e., the quotation from Gregory the Great “vix aut nullatenus [scarcely or not at all].” Where Albert confined himself to the lexicon of scarcity and practical absence, Thomas introduces the more conceptual lexicon of frequency. Indeed, activity frequently leads (frequenter) to sin (TA, In IV Sent., d. 16, q. 4, a. 2, qc. 3, resp.). Thomas then takes up this word in the Summa theologiae: “the frequent vices of merchants [frequentia negotiatorum vitia]” (TA, S. T., IIa IIae, q. 77, a. 4, ad 3).

Thomas retains the same idea of risk that Albert expressed with the notions of difficulty or rarity. However, by using frequenter, then frequentia, Thomas introduces two distinctive tones. First, although there is no question of mathematical quantification before the development of probability calculus, the expression frequenter insists less than Albert’s expressions difficile, vix, or even nullatenus on the fact that commercial activity almost always leads to sin. So there is a kind of alleviation of risk. Admittedly, in Latin, as in modern language, frequency evokes both the idea of regular repetition and a certain closeness of these repetitions, with a primary meaning that expresses abundance (Ernout and Meillet Reference Ernout and Meillet2001, p. 253). However, the notion of frequency paradoxically suggests a lower frequency of occurrence of the merchants’ sinful situation than did the three terms used by Albert.

Second, the notion of frequency brings a more objective character to this risk, by expressing more the approximation of occurrences of the situation than the more subjective difficulty for the agent to avoid it. Although this seems to correspond better to the general tone of Thomas’s expression of risk, which is rather objective, the notion of difficulty put forward by Albert, if Thomas had taken the first part of the quotation from the Ecclesiaticus, could also have been integrated into the lexicon of risk developed by Thomas (Januard Reference Januard2024). Other terms have a subjective dimension. Thus, in his later works, Thomas’s vocabulary incorporates both the objective and subjective dimensions of risk. In addition, these terms introduced later describe more specific aspects of risk. This is the case for prudence, mentioned in De emptione, III, with regard to merchants who behave incaute (without precaution) and imprudenter (unwisely), or, in part, the estimation (aestimatio) of merchants who seek the just price by approximation (TA, S. T., IIa IIae, q. 77, a. 1, ad 1), or of the danger (periculum) of the transport that affects them (TA, S. T., IIa IIae, q. 77, a. 4, ad 2).

The use of the lexicon of frequency marks an even more important step in the conceptualization of risk and its field of application. The expression frequenter seems to be parallel to probabilis (probable), which Thomas uses in his article on usury in the Commentary on the Sentences (TA, In III Sent., d. 37, a. 6). The two founding texts of Thomas’s economic thought, namely the article on usury and the article on commercial activity in his early work, the Commentary on the Sentences, each introduce an adverb that expresses notions that still structure risk today: frequency and probability. Having laid these foundations, Thomas uses more specific vocabulary in his later works: estimation, which, when he uses it to find the just price, refers to an approximation with a margin of error; prudence, or rather imprudence, which refers to behavior that increases the risk of loss; and danger, which deals with risk in terms of the specific possibility of loss. In addition, the initial lexicon will be used again a few centuries later, when it becomes possible to conceptualize and calculate risk.

By choosing the lexicon of frequency in relation to the sin of the merchants, Thomas performs the same lexical and conceptual operation as in using probability to judge the validity of the arguments used to justify the prohibition of usury. He locates his understanding of the activity in that which is not certain. However, he makes a shift to apply this absence of certainty not to the truth of knowledge but to future contingency. In the case of usury, it is a question of uncertainty as to the validity of the argument legitimizing the condemnation of lending at interest. Thomas locates the justification within the order of opinion and argumentation and not of apodictic knowledge by way of demonstration. In the case of trade, it is a question of uncertainty as to the future occurrence of a situation, i.e., of future contingency. Beyond the specific issues of lending and trading, Thomas provides a major framework for understanding the notion of risk. These two uses cover the two main fields of application of risk: the risk of error in the order of knowledge and the risk relating to the future realization of situations.

Towards a Professional and Occupational Risk

We are witnessing not only an evolution in the terminology used to designate the risk of the sin of the merchant, so as to arrive at Thomas’s concept and lexicon of frequency, but also a professionalization of this risk.

The verse from the Ecclesiasticus in the Vulgate and Albert’s article in general use the word negotians, meaning “one who negotiates,” with the substantival present participle indicating the exercise of the activity. We regularly find the verb negotiare (to do business) and the nouns negotiatio and negotium (trade, business), which have a fairly broad meaning (Langholm Reference Langholm1992, p. 176), but the noun negotiator appears only in the introduction to specific objections to trade.

Thomas, for his part, commonly uses negotiator, in TA, In IV Sent., d. 16, q. 4, a. 2, qc. 3, resp., and then in the article of the Summa theologiae in which he cites the verse of the Ecclesiasticus, TA, S. T., IIa IIae, q. 77, a. 4, which repeats the prohibition against clerics. Thomas thus professionalizes this activity by making it a profession and a social status designated by a name, negotiator, the trade or business professional. The term negotians most likely refers to someone who trades for gain (propter lucrum) and who can commit a sin with his lips. There is therefore no difference in activity, but negotians emphasizes the act, whereas negotiator emphasizes the professional social status of the person. Thomas thus truncates the quotation from the Ecclesiaticus by writing negotiator and not negotians, even though the textual tradition of the Vulgate seems unanimous in retaining the word negotians.Footnote ³ Among the possible origins of this evolution, we note that the use of negotiator seems to come more from Thomas’s legal sources. The current usage can be found in Gratian (Gratian, Decretum, II, causa 14, q. 3, c. 3). Thomas even uses mercator, which explicitly refers to the professional activity of trade for gain (TA, De emptione; Politicorum, I, 9; De regno, II, 7 (II, 3); S. T., IIa IIae, q. 77, a. 3, obj 1; q. 78, q. 2, obj 5, and ad 5), although mercatores are condemned by Gratian (Decretum, I, causa 88, c. 11 Ejiciens).

Thomas’s precision is also grounded in medieval economic life. He sees the emergence of a new social class, that of the professional merchants (Le Goff [2010] Reference Le Goff2019, pp. 121–231), who increasingly exercised economic and social dominance (Le Goff [1956] Reference Le Goff2001, pp. 41–67). Well versed in accounting, foreign exchange, navigation, and commercial law (Feller Reference Feller2020, pp. 57–61), they have more money and better information than their clients, and the boundaries of their activity are sometimes blurred between trading and usury disguised as commerce (McLaughlin Reference McLaughlin1939, pp. 95–111; McLaughlin Reference McLaughlin1940; De Roover Reference De Roover1953, pp. 28–29; Ege Reference Ege2014, p. 392). Professional merchants are therefore exposed to a specific risk. The legal precision given by Gratian is echoed in economic life, which justifies the use of its own lexicon to describe the specific nature of the risk of trading in a professional context.

This shift from negotians to negotiator, which takes place as early as Thomas’s Commentary on the Sentences, constitutes for him the first of two stages in the reduction of the scope of the prohibition of commerce. The second step occurs only with the Summa theologiae. Albert presents the first criterion governing trade, the persona (person) criterion, which prohibits buying and selling “from any person consecrated to the divine office, such as a cleric or a monk,” except the fruit of their production (AM, In IV Sent., d. 16, a. 46, ad q. 1). Thomas takes up this idea but limits it to the profession of merchant (negotiator), which is forbidden to those who are prevented from doing so by their office (officio), such as clerics and monks (clericis et monachis) (TA, In IV Sent., d. 16, q. 4, a. 2, qc. 3, resp.). Clerics and monks are typical examples of a broader prohibition, which now concerns only the formal practice of the profession of merchant.

Thomas then made a second restriction, since, fifteen years later, in TA, S. T., IIa IIae, q. 77, a. 4, ad 3, only clerics (clerici) were concerned, without mentioning monks. He thus repeats the prohibition on clerics alone trading (negotiationis ingenio) (Gratian, Decretum, II, causa 14, q. 4, c. 1; see also I, causa 88, c. 1 and c. 9). In this passage of the Summa theologiae, as in the article of the Commentary on the Sentences, Thomas uses negotiator and not negotians. Thomas therefore reduces the prohibition in two ways, by limiting it first to the professional activity and social status of the negotiator, and second to clerics only. However, it can be considered that the cloistered monks are implicitly excluded from the merchant’s activity, in the restrictive sense of the merchant’s profession. In an article explicitly devoted to the professional activity of merchants who trade “for gain,” as opposed to those who trade for “the necessities of life” (TA, S. T., IIa IIae, q. 77, a. 4, resp.), what may appear to be a simplification of the expression or a reduction in the extent of the risk rather reflects a professionalization of this risk. Albert deals with merchants by revolving around activity and profession: Ecclesiasticus 26:28 speaks of negotians (those who trade) and caupo (tavernkeeper). Thomas specifies the field of application of the risk by a clear professional delimitation.

A Risk Incurred by Speech

In the Summa theologiae Thomas makes another change, which concerns the nature of the merchant’s sin and therefore the risk involved. The quotation from Ecclesiaticus 26:28 of Albert’s first sed contra (AM, In IV Sent., d. 16, a. 46, q. 1, s. c.) mentions two sins for two different categories of people: negligence (negligentia) for the merchant (negotians) and the sin of lips (peccatum labiorum) for the tavernkeeper (caupo). Thomas does not use this quotation from the Ecclesiasticus in his Commentary on the Sentences, but he does use it fifteen years later in the Summa theologiae to justify the prohibition of trade for clerics: “The merchant avoids with difficulty the sins of lips [difficiliter exuitur negotiator a peccatis labiorum]” (TA, S. T., IIa IIae, q. 77, a. 4, ad 3). Thomas truncates the biblical quotation in two ways: Not only, as we have seen, does Thomas professionalize this activity by making it a profession, negotiator, where the Vulgate and Albert’s text use negotians, the one who negotiates, but Thomas also eliminates the tavernkeeper (caupo) and negligence (negligentia).

To understand these changes, it is necessary to look at the term caupo, a generic name that can designate the tavernkeeper or the innkeeper but also sometimes the shopkeeper or the merchant, with a petty craftsman or huckster aspect. His use of the spoken word thus seems more important than the object of his activity. In the paragraph of the respondeo dealing with the persona criterion, Albert expands on the activity of taverns and calls the tavernkeeper tabernarius. Priests and monks cannot be merchants because of the debauchery of taverns: “In a tavern, discussions are made up of backbiting [conciliabula fiunt malorum], and the consumption of wine is immoderate [immmoderata consumptio vini], to which the tavernkeeper assures his patronage [patrocinium praestat tabernarius]” (AM, In IV Sent., d. 16, a. 46, ad q. 1).

Is the sin of lips the work of the caupo, who would then be like a tabernarius, and would find its source in the heat of the taverns, or is it linked to the caupo’s activity as a professional merchant? At least, caupo, as opposed to negotians, explicitly refers to a professional. More than the specificity of the agitated nature of taverns, Thomas retains the professional nature of his activity. By choosing to abandon the passage comprising negotians and to replace caupo by negotiator, Thomas has merged the broad activity of trading initially rendered by negotians with the professional practice rendered by caupo.

Then, by deleting negligence (negligentia), Thomas attributes the sins of lips (peccati labiorum), specific in Albert to the tavernkeeper, to the merchant. The articulation formed by two pairs of terms in Albert, negotians – negligentia and caupo – peccati labiorum, becomes in Thomas’s text negotiator– peccati labiorum.

A quick reading could lead to an erroneous interpretation of the disappearance of negligence in TA, S. T., IIa IIae, q. 77, a. 4, ad 3 in favor of the sins of lips, a sin that would not be commercial but simply particularly unsuitable for clerics. This would be consistent with the second reason given immediately afterwards by Thomas for forbidding commercial activity by clerics. This reason is not strictly commercial either but has more to do with the specific way of life of clerics: “Trade [negotiatio] takes up much of the mind by attention to secular things [which] distracts from spiritual things” (TA, S. T., IIa IIae, q. 77, a. 4, ad 3).

These two reasons would not therefore constitute an obstacle to trade per se but to the practice by clerics of such a profane activity. One might think that the text sets out two risks that are specific to clerics but that are not linked to the nature of commercial exchange. The sins are merely relational and spiritual: The sin of lips is simply backbiting and gossiping, which is then associated with the monopolization of the mind.

There are, however, three elements that invalidate this interpretation. First, Thomas truncates the biblical quotation, not by replacing negotians by cleric but by negotiator, so what it says, namely the sin of lips, does indeed concern the merchant profession. Then, at the beginning of his passage justifying the prohibition against clerics, Thomas situates his remarks in the context of what is proper to mercantile activity: Trade is “a species of evil [speciem mali],” “either because it is ordered to earthly profit [ordinata ad lucrum terrenum],” “or because of the frequent vices of merchants [frequentia negotiatorum vitia]” (TA, S. T., IIa IIae, q. 77, a. 4, ad 3). It is therefore more a question of taking up the question of practice by clerics in order to reflect further on the nature of the risk constituted by the sin of merchants. Once again, a look at the lexicon is very useful. The use of the terms gain and frequent sheds light on his point.

Gain (lucrum) here refers to the gain mentioned in his respondeo, which deals with the difference between the professional merchant who trades for gain (propter lucrum) and the master of the domain (œconomicus) who trades for the necessities of life (propter necessarias vitae). The preliminary condition of licitness of the merchant’s activity is that he should have a moderate gain (lucrum moderatum), and the three conditions relating to the purpose are that the merchant should order (ordinat) his activity to feed his family, or to help the needy, or to supply the city (TA, S. T., IIa IIae, q. 77, a. 4, resp.).

The frequency (frequentia) of the vice of merchants refers here to the adverb frequenter used in the Commentary on the Sentences (TA, In IV Sent., d. 16, q. 4, a. 2, qc. 3, resp.). Thomas did not detail the object of the frequency of sin, apart from the criteria persona, tempus, modus. The persona criterion is the very object of the passage in the Summa theologiae, but the tempus criterion, which aims to avoid holidays but also days of possible speculation, and above all the modus criterion, which provides for the absence of fraud and compliance with a licit contract, are specific to the activity of merchants. Unlike Albert (AM, In IV Sent., d. 16, a. 46, ad q. 1), Thomas does not yet include the notion of price and just price in his article in the Commentary on the Sentences to explain his modus and the notion of fraud, but he will do so throughout q. 77, which TA, S. T., IIa IIae, q. 77, a. 4, ad 3 concludes.

The merchant’s risk is therefore that his activity is ordered towards gain, and this risk is high, with a frequency of occurrences, and that it touches on vice, which will be practiced above all through fraud, especially on price.

Another passage in the Summa theologiae, in which Thomas cites Ecclesiasticus 26:28, this time in the version of the Vulgate and Albert, explicitly confirms that the sin of lips is a commercial sin that affects the justice of the exchange:

Thomas retains caupo here, but the tavernkeeper appears here as the example of the professional tradesman. His sin is directly commercial. Language is what enables him to distort the justice of the exchange. It is not a sin linked to the specific nature of his trade and the heat of the taverns, or to the merchant’s idle talk at the marketplace, but a sin of fraud and deceit committed by the merchant.

Finally, the text is not divided into a first part, which would group together the words on the vices of merchants, and a second part, which would group together the sin of lips in the verse of Ecclesiaticus and the overapplication to secular things, but rather there is a break between the sin of lips and the application to secular things. In fact, after stating the vices of the merchants, the quotation is introduced by “quia [because],” a conjunction that indicates continuity and causality. On the other hand, between the quotation and the application to secular things, it is written “et alia causa [and another cause],” which introduces a new part, more focused on the specific life of clerics.

To conclude, the introduction of the causal quia, together with the subject of the modified verse, which is negotiator, make the sin of lips the sin of the merchants. The content of this sin is evoked in the preceding sentence: the pursuit of gain (lucrum) and vice, the frequency of which refers to fraud and indirectly to the just price, i.e., the justice of exchange.

An Informational and Relational Risk to the Justice of Exchange

It remains to clarify the deletion of the lexicon of negligence in the quotation from the Ecclesiasticus modified by Thomas in TA, S. T., IIa IIae, q. 77, a. 4, ad 3. The term is common for Thomas, and the notion appears under another name in his economic thought as early as De emptione et venditione ad tempus, a letter on forward buying and selling of 1262.

At the end of De emptione, Thomas discusses the licit and illicit expenses of merchants, i.e., those that they can recuperate (recuperare) in the price and those that remain at their expense. Thus, they cannot include in the price imprudent expenses, made incaute (without precaution) or imprudenter (unwisely). The adverb incaute is used to describe negligence, whereas imprudenter refers more to incompetence, which leads to forecasting errors. Negligence and incompetence are therefore the two forms of imprudence on the part of the merchant. See De emptione, III; Gardin-Dumesnil (Reference Gardin-Dumesnil1788, p. 544); Quicherat (Reference Quicherat1893, pp. 524, 528); Blaise (Reference Blaise1954, p. 421); Blaise (Reference Blaise1975, p. 465); Ernout and Meillet (Reference Ernout and Meillet2001, pp. 107, 159, 541); Januard (Reference Januard2022a, pp. 258–259). Prudence, here, is a virtue and is not based on statistics, or calculation as a procedure or results (Yuengert Reference Yuengert2012, pp. 57, 74–75; Hirschfeld Reference Hirschfeld2018, p. 179). However, this is consistent with the contemporary approach where imprudence refers to a leftward spread of the curve representing the probability density function (Kimball Reference Kimball1990): The trader does not develop an attraction for risk (in the sense that he would prefer spread distributions to concentrated distributions) but an imprudence in the sense that he would prefer distributions spread in the direction of losses (negative skewness) to concentrated distributions.

Negligence, which is part of imprudence, is not treated for its own sake but for its commercial impact. Thomas does not discuss the risk of negligence from the point of view of the quality of management and the viability of the business but for what it implies for the justice of the exchange. According to Thomas, negligence represents a risk when it leads to a fraudulent increase in the sale price, i.e., not for the success of the business but for the justice of the exchange, and therefore for the sinful moral situation of the merchant. His framework of analysis is therefore relational, not individual, because it concerns the justice of the exchange relationship.

Justice characterizes an act of relationship. Justice manifests a relationship of proportion, thus externally (Lapidus Reference Lapidus1994, p. 436), as the Summa theologiae testifies: “The matter of justice is an external activity” (TA, S. T., IIa IIae, q. 58, a. 10, resp.) and “the object of justice [objectum justitiae]” is “something external [aliquid exterius constitutum]” (TA, S. T., IIa IIae, q. 59, a. 2, ad 3). Thus injustice is the maladjustment of an external act to the right of someone else. It is therefore a matter of the objective and external character of the act (Delos Reference Delos and d’Aquin1932, pp. 194–195, 198–199). However, justice characterizes the act of a just person (Koehn and Wilbratte Reference Koehn and Wilbratte2012, p. 505). This person is in relation with another. Trade activity is presented by Thomas in the Summa theologiae as an act of relationship and as an interaction between people: the discussion, implicitly presented, between buyer and seller, who exchange for “the common interest of both parties” and the satisfaction of needs, with a comparison of benefits and harms (TA, S. T., IIa IIae, q. 77, a. 1); the need for some form of communication about the three characteristics of what is being sold—the nature, quantity, and quality of the object (a. 2); the discussion of cases where communication through price is sufficient and cases where explicit information is necessary (a. 3); and the need for clarification between natural exchange and exchange “for gain,” and between the simple merchant or the merchant-craftsman who improves the good (a. 4).

Negligence is therefore part and parcel of everything that can lead to injustice in the exchange on the part of the merchant. An important part of the merchant’s activity is the act of communicating defects or the price. Then, negligence is contained implicitly in the sin of lips mentioned in TA, S. T., IIa IIae, q. 77, a. 4, ad 3.

The insistence on the sin of lips in what constitutes the last lines of what is undoubtedly Thomas’s last great text on trade does not therefore constitute an omission of negligence but confirmation of its understanding from a relational perspective and its integration into a broader category, which becomes the major risk for Thomas: the sin of lips.

One must not forget that speech has legal status. In Roman law, and especially in economic affairs, contracts are mostly oral contracts, often with witnesses (Macqueron Reference Macqueron1971, p. 49). One may resort to a written document, so-called instrumentum, but it is not mandatory. Formal written (litteris) contracts are scarce. Sin may lie in the injustice of the content of the speech, which would make a contract unjust. In addition, one can imagine, for instance, in the case of the contact verbis, where a formula must be recited exactly, a deviation that would deliberately render it invalid. The injustice created by communication is therefore a legal injustice on contracts.

This reduction of the injustice of exchange to the sin of the merchant’s lips makes an epistemological statement about the nature of exchange and an anthropological statement about the nature of its agents. On the one hand, the risk incurred by the merchant is a risk of sin of lips because his action is a relational action but even more so an action of the relation through speech. On the other hand, the injustice of the exchange is an injustice of the word, and therefore of the information communicated. The risk for the merchant is that the information he gives about the quality of the good or the just price is erroneous and that he should find himself in a situation of sin.

This makes it easier to understand one of Albert’s enigmatic comments in the respondeo of his article. He quotes the Gloss on the verse of the Ecclesiaticus in his first sed contra in which, after quoting the verse and considering that the merchant did not always sin, he nevertheless incurred a critical danger (discrimen), which justified that no one should incur such a risk by engaging in trade. In order to establish the licitness of trade, Albert went a step further and considered that perjury was more serious than the price: “The worst act, not an honest thing, that is condemned—one who, through excessive ambition, burdens his mind more with perjury [perjurio] than with price [pretio]” (AM, In IV Sent., d. 16, a. 46, ad q. 1).

This passage can be understood as a relativization of commercial fraud and the injustice of the price. The danger, or risk of maximum loss (the seriousness of the sin and the associated moral penalty), would not be so great as to justify prohibiting trade. Perjurers would be exposed to a much higher maximum loss. Perjury is more serious than lying, because it does not offend only one’s neighbor; it offends God by calling upon Him to confirm what is false or illicit (Casagrande and Vecchio Reference Casagrande and Vecchio1991, p. 208). The risk would thus be high in frequency but limited in magnitude. The same idea appears in Thomas’s works: There is no penalty for an unjust price other than restitution (TA, S. T., IIa IIae, q. 77, a. 1, ad 1). This is a principle of medieval commercial justice whose requirement is first and foremost moral and religious, in order to receive absolution (Todeschini Reference Todeschini1994, p. 135; Dejoux Reference Dejoux2014, p. 854).

However, the combination we can propose—the combination of, on the one hand, Albert’s comparison in the Commentary on the Sentences between the abusive price charged by the merchant and perjury, and, on the other hand, the sin of the merchant’s lips, which completes Thomas’s entire commercial treatise in the Summa theologiae —opens up another way of understanding. It may be seen as a reprise of Gratian’s argument formulated 100 years earlier: “he who buys and sells cannot avoid lying and perjury [qui emit et vendit sine mendacio et periurio esse non potest]” (Gratian, Decretum, I, causa 88, c. 11, Ejiciens). Albert’s sentence is therefore consistent with Gratian’s statement: The offence of perjury and the offence of price both concern the merchant. Augustine of Hippo’s Commentaries on the Psalms were even more precise: If the merchant not only lies about the price but also swears, he is blaspheming (Enarrationes in Psalmos, LXX, §17). The merchant’s oral sins thus relate to the price.

For Albert, fraud is an infringement of the law, either by a defect in the contract or by failure to comply with a licit contract. This fraud is oral, by the sin of lips, as says the verse of the Ecclesiasticus that the Gloss comments on here. However, the legal framework laid down by Albert makes it a form of perjury. Thus, for Albert, the seriousness of the merchant’s sin would not be his illicit gain but his perjury, his breach of contract. For Thomas, who does not take up the juridical tone of perjury but retains its orality through the sin of lips, and for Albert, who also holds to orality and the sin of lips, the seriousness of the sin would lie in the use of speech and communication to deceive, and thus to undermine the justice of the relationship. The maximum risk (seriousness of the moral fault) incurred therefore comes from the act of using false speech rather than from the desire to obtain illicit gain by means of an unjust price.