Scholastic Logic and Cartesian Logic Lucian Petrescu FNRS-Université libre de Bruxelles 1. Introduction As Roger Ariew shows, one of the most fascinating challenges for the authors trying to create a Cartesian complete course on philosophy was com- ing up with a Cartesian Logic based on the existing texts of the master (Ariew 2014). Were the few simple rules from the Discourse on Method the “logic” of Descartes? Were the Rules for the Direction of the Mind “logic”? How can we even have a logic without syllogism? When looking at the authors stud- ied by Ariew one finds that the best that they could come up was adding some Cartesian elements on what remains basically a traditional Aristotelian Logic. It seems that there was no Cartesian Logic after all. I want to show here that Cartesian Logic is something else, not exactly “Logic” in the way that was taught in the first year of college, but some- thing meant to replace Aristotelian Logic once we have done away with syllogism. A treatise such as the Rules for the Direction of the Mind belongs to a new genre, one that comes out of the transformation of Aristotelian Logic in the early seventeenth century. I call this genre the “Art of dis- course.” In the Cartesian corpus the most complete incarnation of this genre is to be found in the (incomplete) Regulae; the preface written for the Essays of 1637, the Discourse on Method, while containing some elements of the art of discourse such as the famous “rules,” remains a preface and not a system- atic treatise. While the textual sources of Descartes’s Regulae and its relationship with antique or Renaissance authors have been well scrutinized by Cartesian scholarship, its immediate context, which is that of the early seventeenth- century treatises of Logic, is not well known. This is understandable be- cause the topic itself is very difficult: what Renaissance Logic and early seventeenth-century Logic is remains hard to master, in spite of some eminent Perspectives on Science 2018, vol. 26, no. 5 © 2018 by The Massachusetts Institute of Technology doi:10.1162/posc_a_00287 533 Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/posc_a_00287 by guest on 26 September 2021 534 Scholastic and Cartesian Logic research done by Renaissance scholars ever since Die Logik der Neuzeit of Wilhelm Risse (Vasoli 1968, Jardine 1974, Gilbert 1960, and others).1 However, this is a project that needs to be done if we want to understand the motivations of Descartes’s text—that is, not so much the tradition on which he draws and in which we are to place the Regulae, but rather the tra- dition against which it reacts. Marion’s edition and early work on the Regulae remains the only extensive study on the Aristotelian sources of the text (Marion 1975; Marion and Armogathe 1977; Marion 1978). Marion looked at the Regulae as a direct confrontation with Aristotle, which, as necessary as it is, may give the impression that Descartes was arguing directly against Aristotle, bracketing the entire Aristotelian tradition. The only extensive study on the immediate context of the Regulae is that of André Robinet, which traces, as he puts it, an axis, understood as a continuity of thinking, between Pierre de la Ramée and Descartes, and inscribes Descartes in the Ramist current that traverses the Northern half of Europe in the sixteenth century (Robinet 2000).2 This reconstruction definitely has its merits and one can certainly recognize elements of “Ramism” in the Regulae if one is set to look for them. The conceptual language of the Regulae, terms such as ingenium, invention, deduction, mathesis universalis, and method, lead directly to the Ramist vocabulary. However, one should be careful when presenting Descartes as a represen- tative of something, in the continuity of something, or on a certain “axis,” because he always presented himself in opposition with everyone. Descartes has constantly criticized “the dialecticians” and his adversaries are not only the Aristotelians that he later thought to replace, but also some of the mod- erns. Anti-Aristotelians such as Pierre de la Ramée are rather to be seen as rivals of Descartes, as figures that he would be susceptible to oppose as much as he opposed the Aristotelians. Descartes would not have seen him- self as another Ramus, but as a new Ramus. What counted as Logic for Descartes was foremost the Jesuit Logic that was taught in schools such as the Collège de La Flèche. My purpose is to show that Aristotelian logic in the early seventeenth century was already understood not as an instrument that forms automatisms of thinking to be used by other sciences, and not as a science of demonstration centered on the Posterior Analytics;an“art of discourse,” understood in the perfectly Cartesian sense of directing one’s ingenium in the search of the truth. It 1. Jardine, 1974, esp. pp. 17–58, “Dialectic and Method in the Sixteenth Century.” On Pierre de la Ramée, besides the edition of La Dialectique (1555) of Michel Dassonville (1974), the classical study remains that of N. Bruyère, Méthode et dialectique dans l’œuvre de La Ramée (1984). 2. See also the critique of Robinet’s thesis by F. de Buzon 2005. Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/posc_a_00287 by guest on 26 September 2021 Perspectives on Science 535 is this logic, wholly Aristotelian in its constitutive elements, but defined in a non-Aristotelian way as the art of discourse, that Descartes has in mind when he sketches his own Rules for the direction of the mind. The Regulae arrive at an important moment in the history of Logic. Aristotelian Logic used to be a preparatory discipline, the first thing taught in the Faculty of Arts or in the first year of college as an instrument that teaches the student how to give proper scientific demonstrations when he would be faced with the sciences of real things, such as physics, meta- physics, or medicine. Seventeenth-century logic becomes a science of the operations of the mind, a critique of reason, having as its object the proper scientific discourse. The art of discourse has been associated by scholars with more “innovative” strands of the Nordic Renaissance: either Ramism, Philippo-Ramism, Baconianism, or Northern Italian discussions of method. The second point I want to make is that this evolution of Logic is not a criticism of Aristotelian Logic or something that comes from the outside of the Aristotelian tradition, as the lecture of some novatores has led us to believe. If we look at more conservative strands, such as Jesuit philosophy, one can see this transformation of Logic taking place within the Aristotelian tradition itself. Jesuit Logic was also an “art of discourse” and it developed into one not under the influence of Ramism, but as an organic growth from within the medieval tradition. The art of discourse in the seventeenth cen- tury is simply what seventeenth-century Logic is meant to be, and its func- tion is to direct the mind, regardless of whether the material it deals with comes from Aristotle, Melanchton, Pierre de la Ramée, or Descartes. 2. Logic between Aristotelianism and Ramism According to Wilhem Risse’s monumental Bibliographia logica (1965), there are some 20,000 works on Logic published during the sixteenth and the seventeenth centuries throughout Western Europe. The breadth of this material defies any effort of systematization. I propose to start getting a sense of the picture from one of the most influential logicians of the century, Franco Burgersdijk (1590–1635), professor at the University of Leiden in the 1620s when Descartes was writing the Regulae, and later rector of the same university (see Bos and Krop eds. 1993). Burgersdijk’sLogichada tremendous success in England and was taught in universities until well into the eighteenth century. In his Institutionum logicorum libri duo (1626), where he proposes a quite innovative “system” of Logic, he divides the recent logicians into three classes or three currents, each with its own faults. In the first class there are those that follow Aristotle step by step (kata podas). They put together Aristotle’s Organon from his writings, extract the same principles from them, follow the same method, and even give the same examples. They Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/posc_a_00287 by guest on 26 September 2021 536 Scholastic and Cartesian Logic produce merely Introductions to Aristotle (Isagoge) that are useful books for understanding Aristotle’s doctrine but cannot count as systematic Institutions of Logic. Aristotle’s books are admirable taken individually, says Burgersdijk; butitisdifficult to extract an Organon from them. There are problems of edition and transmission of texts: we do not know the order in which Aristotle has written or edited them, and they are obviously written in dif- ferent occasions and for different purposes. In short, putting Aristotle’slog- ical books together in one volume, as some recent authors do, will do nothing to bring us closer to a complete Logic. What would then be a complete Logic? It should treat of four “instru- ments”:definition, division, syllogism, and method, the landmark tetrad of Burgersdijk Logic. Aristotle and his followers only speak of one of them, syllogism, and even of this one they give an incomplete treatment, ignor- ing some of its forms. Here Burgersdijk invalidates the entire project of the Aristotelian courses on philosophy that were starting to be developed in Jesuit colleges at the turn of the century. Not only so, but he invalidates the Aristotelian corpus itself—very little of the material found in Aristotle’s books pertains to Logic proper, he says.