LA FLÈCHE, COLLEGE OF. The Jesuit Collège Henry IV, the school Descartes attended (ca. 1607–15), was founded in 1604 at La Flèche in Anjou. The student population of La Flèche was diverse, geographically and culturally. The college accepted boys from all corners of France and from all walks of life. During Descartes’s days, its boarders numbered approximately 100, and it taught, in addition, about 1,200 external, or day, students. Like all other Jesuit schools at the time, the curriculum at La Flèche consisted of four or five years of humanities, that is, French, Latin, and Greek language and literature, a year of rhetoric, plus three years of the collegiate curriculum: ethics and logic, mathematics and physics, and metaphysics.
In the Discourse on Method Descartes represented himself as dissatisfied with the education he was given at La Flèche: “in my college days I discovered that nothing can be imagined which is too strange or incredible to have been said by some philosopher” (AT, vol. VI, p. 16). However, he seemed more favorably disposed toward the college in his correspondence. There Descartes asserted: “it is extremely useful to have studied the whole philosophy curriculum in the manner it is taught in Jesuit institutions,” and, to give his teachers their due, “there is no place on earth where philosophy is better taught than at La Flèche” (AT, vol. II, p. 378). Descartes praised the academic rigor of its teaching, its discipline, and its social ethos.
LA FORGE, LOUIS DE (1632–ca. 1666). La Forge was a French physician who became an enthusiastic Cartesian. He worked on the 1664 edition of Descartes’s Treatise on Man, providing it with extensive annotations and illustrations (the latter in collaboration with Gérard van Gutschoven). His main publication was Traitté de l’esprit de l’homme (1666). It is an important statement of occasionalism, the metaphysical doctrine of causation that became dominant with the later Cartesians. La Forge extended the Cartesian program by discussing in detail the mind and its union with the body.
LA GRANGE, JEAN-BAPTISTE DE (ca. 1641–post-1680). De la Grange joined the Oratory in 1660. He taught philosophy at Montbrison and Mans and theology at Troyes. He left the Oratory in 1680 to become curé of Chatres, near Paris. De la Grange wrote a very critical two-volume treatise against the new philosophy, Les principes de la philosophie contre les nouveaux philosophes, Descartes, Rohault, Régius, Gassendi, le p. Maignan, etc. (1675–79). In this work, he acknowledged the widespread appeal of Cartesian philosophy, but he obviously also wished to caution against that appeal.
One of the primary targets of de la Grange’s attack was an unnamed opponent who had just published such views as “some things are known directly through themselves and others are known only through consciousness or inner sensation. . . . As for corporeal things, they are not intelligible by themselves, and thus we can see them only in God” (Les principes de la philosophie, p. 78). Nicolas Malebranche, of course, was the philosopher who presented and defended the claim that we see all things in God, together with the radical occasionalism that denies causal efficacy to finite things, including minds; Malebranche had entered the Oratory in 1660 and had just published the first volume of his Recherche de la vérité. Thus, for de la Grange, Descartes looms as the corrupter of orthodoxy who can even seduce members of the Oratory. De la Grange continued with his refutation of the views of his unnamed opponent; he also wrote critical discussions of Cartesian views on such topics as the possibility of plural worlds, animal rationality, the accidents of the Eucharist, the nature of place, the infinity of the world, the possibility of the void, and the motion of the Earth.
LA MOTHE LE VAYER, FRANÇOIS DE (1588–1672). La Mothe Le Vayer trained and practiced as a lawyer in Paris. He became a member of the Académie Française (1638) and teacher to the Duke of Orléans (1647) and Louis XIV (1652). He belonged to the circle of writers called libertins, or freethinkers, known for their relativism. His first work, Dialogues faites à l’imitation des anciens, was published in 1630, with false title pages, under a pseudonym, and reissued in two volumes with additions in 1631. It contained much material thought shocking for its time. Like Pierre Charron before him, La Mothe argued that, of the main schools of philosophy, skepticism is the most compatible with Christianity, despite its method of displaying the uncertainty of received opinion. What is more, it is best situated to accommodate the diversity of religious belief and observance from ancients to moderns. Among the issues also considered by Descartes, La Mothe reflected on whether theology is a demonstrative science. He considered arguments for the existence of God and doubted their effectiveness against atheists.
LAMY, BERNARD (1640–1715). Oratorian philosopher. Lamy taught humanities and philosophy and studied theology at various Oratorian colleges (1661–75). He was teaching at the College of Angers in 1673 when he got into trouble for his Cartesian ideas. In 1671 Louis XIV had banned the teaching of the new philosophy from French colleges. Because of this, censors examined Lamy’s lectures and objected to 10 propositions they identified as Cartesian. They objected to Lamy’s definition of extension as the essence of body and to his rejection of substantial forms, which, they said, did not allow for an explanation of the Eucharist. They ridiculed Lamy’s endorsement of the cogito, his assertion that children think in their mother’s womb, and his thought that sensations such as pain are experienced in the soul, not in the body. They also objected to Lamy’s opinions that God is the principal cause of motion, that the quantity of motion is conserved, and that the only kind of movement is local motion. As a result, Lamy was expelled from Angers in 1675. In 1676 he was sent to the seminary in Grenoble, where he was given a chair in theology. He was in Paris from 1686 to 1689 and afterwards in Rouen, where he stayed for the rest of his life. Lamy is best known for two pedagogical books, L’art de parler (1675), a manual of rhetoric which was often reprinted, and Entretiens sur les sciences (1683), a collection of essays that discuss the proper way of teaching a variety of subjects to young students.
In Entretiens sur les sciences, Lamy showed himself to be a Cartesian, but limited his approbation of Descartes. He discussed, for example, the air pump and the experimental knowledge derived from it, knowledge he said that went beyond what Descartes understood. He also claimed that Descartes gave incorrect explanations of various phenomena because of his lack of experiments. However, he credited him with having opened the path of mechanism; as he said, unless they can explain it mechanically, people no longer believe that something is known. Lamy praised Descartes for his account of mind and the union of mind and body as the philosopher who has spoken the best about the mind and who has distinguished with the greatest clarity its functions from those of the machine of the body. According to Lamy, before Descartes nobody had shown as clearly the relation of man to God.
LANGUAGE. From his earliest works Descartes was fascinated by the phenomenon of language, not primarily as a subject of study but as a model for our relation to the external world. In his view perceptions are not pictures but signs: “If words, which signify nothing except by convention, suffice to make us think of things to which they bear no resemblance, then why could nature not also have established some sign which would make us have the sensation of light, even if the sign contained nothing in itself which is similar to this sensation?” (The World, AT, vol. XI, p. 4). But the problem of language also interests Descartes because of its bearing on the question of animal souls. Is it really likely that animals have no mind or soul if “animals express their feelings and passions by their kind of language and use signs to show their anger, their fears, their love, their pains, their regret for having done evil”? (Alphonse Pollot to Descartes, February 1638, AT, vol. I, p. 514). But according to Descartes “one must not confuse speech with the natural movements which express the passions and which can be imitated by machines as well as by animals; nor should we think, like some of the Ancients, that the beasts speak, although we do not understand their language” (Discourse V, AT, vol. VI, p. 58). In fact, the “natural language” by which animals and men express their feelings and passions is not indicative of mind or consciousness. The language spoken by humans, however, is based on conventions. Conventional language, on the other hand, is one of the signs by which humans can be distinguished from animals or automata.
But language is also a source of obscurity and error. In many learned disputes “the problem is one of words” (Rules XIII, AT, vol. X, p. 433). Not only are most of the problems of traditional philosophy nothing but verbal disputes; words can also be used to conceal ignorance. Given the fact that, “when we store the concepts in our memory, we always simultaneously store the corresponding words . . . the thoughts of almost all people are more concerned with words than with things; and as a result people very often give their assent to words they do not understand, thinking they once understood them, or that they got them from others who did understand them correctly” (Principles I, art. 74, AT, vol. VIIIA, pp. 37–38).
Finally, Descartes deals with the issue of a universal language in reaction to an unidentified project about it (to Marin Mersenne, 20 November 1629, AT, vol. I, pp. 76–82). Each language consists of two elements, meaning and grammar, and according to Descartes it is not impossible but impractical to construct a universal language because such a language would have to be learned on the basis of a natural language, which inevitably produces differences in (and difficulties of) pronunciation. Still, the project could be the basis for a new system of written signs, but most people would find even that too much trouble. In what is visibly a second thought, however, Descartes introduces the notion of a system of signs analogous to that of the symbols and numbers of arithmetic. We have a system of natural numbers and rules for combining and manipulating them, because we have an orderly and hierarchical system of numerical concepts, so, if we could devise an orderly system of all thoughts, we would also have the means of creating a universal system of signs, in which we can express and produce every possible thought. Accordingly, a universal language should be based not only on true philosophy, but also on an exact enumeration of the simple ideas of the imagination. In the end Descartes sees this as a utopian project.
LAWS OF NATURE (LOIS DE LA NATURE, LEGES NATURAE). Descartes first uses the expression “laws of nature” (which until far into the 17th century will keep a normative connotation) in a letter to Marin Mersenne of April 15, 1630, in which he reacts to “an evil book,” in which, possibly, it was claimed that God is subject to the laws of logic (see atheism). According to Descartes, however, it is blasphemous to believe that eternal truths are independent of God. On the contrary “God has established them as laws in nature, just as a king establishes laws in his realm.” Moreover, we can understand those laws simply by considering them, that is, they are evidently true. And finally, they are all, Descartes claims, “inborn in our minds” just as a king would print his law in the hearts of his subjects.
An objection considered by Descartes was that, in that case, God could change those “eternal truths.” And, indeed, he could if his will could change. However, God’s power is incomprehensible. Accordingly, we may assume that God can do whatever we understand, but that there are many other things he could also do which we do not understand. Indeed, it would be a great temerity to believe that our imagination has as much extension as his power. That this has something to do with the laws of nature or what we would call the laws of physics is clear only by the fact that Descartes tells Mersenne that in two weeks he will put this in his physics (at the time he was writing The World). Usually, however, eternal truths are either demonstrated mathematical truths (like the Pythagorean theorem) or general axioms (like “the whole cannot be smaller than the sum of its parts” or “two contrary propositions cannot be true at the same time”). “Laws of Nature” or “Laws of God” on the other hand were generally understood to be prescriptive, normative laws (such as “thou shalt not kill”), which according to many people were inscribed in the heart. Finally, we do not know whether this was the idea of laws of nature that actually did find its way to Descartes’s physics—indeed, Descartes asks Mersenne to publicize this opinion (without naming him), “so I can know the objections one could make against them.”
In any case, “laws of nature” do appear in Descartes’s physics. The first time is in the context of Descartes’s “fable” that God creates a new world without using more than matter (indefinite three-dimensional extension) and local motion. In this fable several ideas from the letter to Mersenne can be discerned: 1) God can create whatever we can imagine; 2) it is much easier to ascribe limits to our thoughts than to the works of God, which can be seen as the equivalent of the idea that God can do many things which we do not understand; 3) there are laws of nature because God cannot change. Still, the “laws God has imposed on nature” (World VII, AT, vol. XI, p. 36) do not seem to be arbitrary at all once we suppose that God created matter and local motion. For “nature” is “matter itself insofar as I consider it with all the qualities I have attributed to it together, under the condition that God continues to preserve it in the way he created it.” But it cannot be denied that in nature there is also change, which, given God’s immutability cannot be attributed to him but must be attributed to nature. Finally, the rules according to which these changes occur are called laws of nature, which Descartes also calls the secondary and particular causes of the various motions we see in separate bodies. Accordingly, with respect to the eternity of the laws of nature, the point of God’s immutability is not to make them as eternal as God himself but to prevent him from interfering with matter and motion as they were once created, that is, their quantity and their inherent laws.
However, God’s immutability also intervenes on a lower level, namely, that of the laws themselves, which according to the Principles can be known on the basis of God’s immutability. The first law is that “every particular part of matter continues to be in the same state as long as a meeting with other parts does not force it to change it” (World VII, AT, vol. XI, p. 38; Principles II, art. 37, AT, vol. VIII-A, pp. 62–63); the second law that in a collision between two bodies no (material) body can lose anything but the exact quantity of motion which the other acquires and vice versa; and the third law that, if a body moves, it tends to continue its movement in a straight line. The second law in particular (in the Principles, the third law) is the basis for more specific laws of collision and perhaps also for the laws of statics. In sum Descartes thinks of “laws of nature” not as empirical laws or as formulas concerning a constant relation between two or more variables, but rather as fundamental laws that are constitutive of nature.
LE BOSSU, RENÉ (ca. 1635–80). A French Genévofain about whom Mme de Sévigné remarked in 1676 that he is “Jansenist, that is to say, Cartesian.” Le Bossu was a proponent of the strategy of “Aristotelianizing” Cartesianism, or perhaps “Cartesianizing” Aristotle, in order to render Descartes’s views more acceptable to proponents of scholastic philosophy. As he saw the situation, Aristotle had been teaching beginners, and so started with what was obvious to everyone, the sensible things around us, for example, and asked what they were made of. Descartes, at a more advanced stage of science, considered the matter common to everything, which is extended substance, and every particular is given a form by the way that general matter is shaped. Their principles are therefore not so opposite to one another. This strategy is reflected in Le Bossu’s Parallèle des principes de la physique d’Aristotle et de celle de René Des Cartes (1674), which emphasizes the compatibility of Jacques Rohault’s brand of Cartesian physics with Aristotelian categories. The strategy contrasts with the view of Cartesians such as Antoine Arnauld and Nicolas Malebranche that Descartes offered a Platonic form of philosophy similar to that found in the work of Augustine.
LE GRAND, ANTOINE (?–1699). Le Grand joined the Franciscans at Douai, where he was born and educated, and where he taught philosophy. He was sent by the order as a kind of missionary to England. There he divided his time between his studies and administrative duties. He wrote a popular version of Descartes’s philosophy in the form of a scholastic textbook. He first published it as Philosophia veterum e mente Renati Descartes, more scholastica breviter digesta (1671) and expanded and republished it as Institutio philosophia, secundum principia Renati Descartes, nova methodo adornata et explicata ad usum juventutis academicae (1672). It was then translated into English and published as Entire Body of Philosophy according to the Principles of the famous Renate Descartes (1694). The English edition presents itself as the 17th-century equivalent of a coffee-table book, illustrated “with more than an hundred sculptures [that is, engravings],” and “Endeavoured to be so done, that it may be of Use and Delight to the Ingenious of Both Sexes.”
Le Grand’s tactic in the book was to produce a Cartesian philosophy that could be used in the schools, accepting scholastic terminology, but interpreting it in a Cartesian fashion. For example, Le Grand used the scholastic talk of prime matter and substantial form in his account of matter. According to Le Grand, the Aristotelians’ prime matter is nothing but an inadequate conception of a body, as it may be conceived by us without any shape, hardness, softness, color, or any other modifications, and only as extended, consisting of three dimensions. Four propositions agreed upon by both Cartesians and Aristotelians follow from this: 1) Prime matter is without form, because the notion of extension is abstracted from all modification belonging to the essence of a body. 2) The matter of all things is the same. 3) Matter is capable of all forms. 4) A body as such, or prime matter, is incapable of being generated or corrupted. This results in a truly Cartesian Aristotle.
LEIBNIZ, GOTTFRIED WILHELM (1646–1716). Leibniz attended the Universities of Leipzig (1661–66) and Altdorf (1666–67), graduating with advanced degrees in law and in philosophy. He refused an academic position, preferring instead to become a courtier. He entered the service of the Elector of Mainz and, in 1672, he was sent on diplomatic business to Paris, where he immersed himself in Descartes’s philosophy. Leibniz returned to Germany in 1676; for the rest of his life, he served as counselor, mining engineer, head librarian, and historian to the court of Hanover. He is usually considered as one of the three principal Continental Rationalists, along with Descartes and Baruch Spinoza. This designation, however, represents very little of Leibniz’s multifaceted philosophical personality. There is little of Descartes’s philosophy that Leibniz did not criticize, from the cogito as first principle of knowledge, to God’s veracity as the criterion of truth, to God’s existence being derived from the idea we have of him, to God’s creation of the eternal truths, and so forth.
Leibniz’s positive doctrines also reveal his opposition to Descartes’s various positions. For example, in the “Discourse on Metaphysics,” Leibniz develops the notion of an individual substance so as to distinguish the actions of God from those of creatures. The nature of an individual substance is to have a notion so complete to allow us to deduce from it all the predicates of the subject to which this notion is attributed. Several of Leibniz’s metaphysical doctrines follow from this. Two substances cannot resemble each other completely and differ only in number. A substance can begin only by creation and end only by annihilation. Every substance is like a complete world and like a mirror of the whole universe, expressing, however confusedly, everything that happens in the universe, whether past, present, or future. As further consequences of his view of substance, Leibniz argues against Descartes that extension cannot constitute the essence of any substance. He rehabilitates the scholastic substantial forms as the essence of extended substances. He also distinguishes between certainty and necessity: The truth of each event, however certain, is nevertheless contingent, being based on the free will of God, whose choice always has its reasons, which incline without necessitating. And he further argues for the thesis that everything that happens to a substance is a consequence of its idea or of its being, and that nothing determines it, except God alone. Thus he rejects Descartes’s views of human freedom and error.
LEIDEN, UNIVERSITY OF. The University of Leiden, founded in 1575, allegedly as a reward for the heroic defense of the city during the Spanish siege of 1574, was the first university on the territory of the new republic. After a hesitant start it soon developed into an internationally famous institution, renowned for the quality of its humanistic studies, its rich collection of oriental and classical manuscripts, and its “Dutch” school of mathematics, destined primarily for the education of military engineers and providing lessons in advanced mathematics.
Descartes’s first contacts with Leiden University date from June 27, 1630, when he matriculated as a student in mathematics. The reason presumably was that Jacob Golius (1596–1667), the professor of oriental languages and mathematics, had brought with him from the Levant an Arabic version of Apollonius of Perga (ca. 262–ca. 190 BC), containing three missing books (V–VII) of his work on conic sections. The discovery of these texts caused a great stir among mathematicians throughout Europe and was also of great importance to Descartes’s optics. This short stay laid the foundation for Descartes’s friendship with Golius, and, possibly, other Leiden personalities such as Abraham Heidanus (1597–1678), who later became professor of theology.
It is not until 1644, however, that there are any signs of Descartes’s philosophy being discussed among professors and students. Adriaan Heereboord in particular submitted Cartesian propositions for disputation, albeit in an eclectic spirit. Since he was also deputy dean of the Statencollege (a theological college for bursars of the States of Holland), whose dean was the orthodox theologian and poet Jacobus Revius, this led to serious difficulties that, however, became public only in 1647. In that year Revius started a series of disputations in which he wanted to discuss the whole of Descartes’s philosophy to test it against orthodox criteria. In fact, no more than five disputations were organized, because the university administration (the “Curatores,” recruited among the States of Holland) prevented its continuation. In those disputations Revius attacks the Cartesian method of doubt, which he finds impious, and the Cartesian idea that God is his own cause, which he finds contrary to God’s majesty. God’s essence being inscrutable, it is blasphemous, according to Revius, to apply the category of causality to God. Blasphemy was also the word used by another Leiden professor of divinity, Jacobus Trigland (1652–1705), who blamed Descartes for entertaining the idea that God could be a deceiver.
When Descartes heard of these events in the spring of 1647 he wrote a long and violent letter to the Curatores. But to Descartes’s exasperation, their only reaction was a decree that forbade professors and students to use Descartes’s name or to discuss his theories in public lessons and disputations. Although Descartes’s irritation was understandable, the decree was not an attempt to intervene in philosophical debate. For one thing, public lessons were only a small part of academic routine—advanced courses were given in the form of private lessons at the home of the professor. It also remained possible to take up the problem of magnetism, for example, and to discuss Descartes’s theory as one among other solutions of that problem. In fact, the only thing really impossible was to make the philosophy of Descartes as such the subject of a public lesson or disputation—which was precisely what Revius wanted.
But the decree did not stop all trouble. Toward the end of the year 1647 a violent quarrel broke out during a disputation of the Aristotelian Adam Steuart, who attacked Descartes’s idea that God is the cause of himself (attributing it to a “newfangled philosopher”). Cartesian students challenged him either to withdraw his thesis or to name the philosopher who held this idea. In December Revius published a book against Descartes’s Discourse called Methodi cartesianae consideratio theologica (“A Theological Consideration of Descartes’s Method”). Descartes responded to both incidents at the end of his Notes Against a Program, which was published at the beginning of 1648. Both Revius and Steuart countered by publishing new pamphlets. Heereboord also reacted by publishing an open letter to the Curatores, in which he provides a general picture of the situation. In reaction to all this the Curatores issued another decree (February 1648), forbidding all teaching of metaphysics, whether Cartesian or Aristotelian—a decree displeasing not only to Heereboord, who loved metaphysical discussions, but also to the theologians, who believed that theology requires a metaphysical framework.
However, the Curators were determined to root out the problem not by taking sides with one or the other, but by strictly separating the Faculties of Philosophy and Theology. In practical terms, however, this amounted not only to emancipating philosophy from its propaedeutic role, but also to promoting a non-scholastic type of theology, so in actuality the administration did favor particular trends: Cartesianism in philosophy (as long as it limited itself to physical problems), and Coccejanism (so called after its founder Johannes Coccejus) in theology (which, although certainly orthodox, rejected the formalism of Voetian theology). That is probably also the reason why the measures taken by the administration were not entirely successful and had to be confirmed several times, especially in 1656. In 1656 the continuing discussion over the theological consequences of Copernicanism, which all over the republic became the hallmark of Cartesian philosophy, even led to a unique intervention by the States of Holland, which explicitly stated that “the freedom to philosophize” should not undermine theology. Cartesians were free to do physics but should leave all theological problems, including that of reconciling heliocentrism with Scripture, to the Theological Faculty. Meanwhile, the Curators went on appointing Cartesians: Johannes de Raey in 1651; Arnold Geulincx in 1662; Theodor Craanen (1620–90); Burchard de Volder (1643–1709) in 1670; and Christoph Wittich in 1672. As a result, serious incidents continued to occur.
The publication of Lodewijk Meyer’s Philosophy the interpreter of Scripture (1666) and later Baruch Spinoza’s Theologico-political treatise (1670) and Posthumous works (1677) caused new tensions, culminating, in January 1676, with the official condemnation of 20 propositions. Although many of the condemned propositions were Coccejan and some simply Spinozist (20. “Philosophy is the interpreter of Scripture”), many had a Cartesian ring: 6. “In matters of faith clear and distinct perceptions are a norm and measure of truth.” 12. “[The world] is infinitely extended, so it is impossible that there be more than one world.” 13. “The human soul is no more than a thought and without it man could nonetheless live and be moved.” 15. “The human will is truly free and undetermined and as infinite with regard to its objects as the will of God.” 16. “God can deceive us if he wants.” 17. “We have a faculty by which we can prevent error; error however is only in the will.” 18. “All things, even God’s existence, must be doubted in such a way that they are taken to be false.” 19. “Men have an adequate idea of God.” The Cartesians published a reaction in which the 20 theses were extensively discussed mainly to show that they could be reduced to a misunderstanding of Cartesian or Coccejan positions. Heidanus, who took the responsibility, was immediately dismissed. But even this draconic measure did not stop the spread of Cartesian ideas; indeed, that was stopped not under the influence of any external pressure, but by the rise of Newtonian ideas, first introduced on the continent by de Volder. Indeed, it could be argued that the foundation in 1675 of the “physical theatre,” which was actually a laboratory of physics, and the introduction of experimental courses not only diverted the attention of the public from metaphysical controversies, but also prepared the eventual demise of Cartesianism. In fact, the very restrictions under which Cartesians worked stimulated them to find new and original ways of doing philosophy.
LE VALOIS, LOUIS (1639–1700). A French Jesuit from Caen, about whom little is known beyond the fact that he wrote the Sentimens de M. Descartes . . . opposez à la doctrine de l’Eglise et conformes aux erreurs de Calvin sur le sujet de l’Eucharistie (1680) under the pseudonym Louis de la Ville. In this work, Le Valois repeated the charge of Calvinism that had been directed a decade earlier against the Cartesian account of transubstantiation in the work of Robert Desgabets. However, his critique is distinctive in extending this charge to Pierre Gassendi and the Gassendists. This feature of the Sentimens explains why it received responses not only from Cartesians such as Nicolas Malebranche and Antoine Arnauld, but also from the Gassendist François Bernier. The controversy stirred up by the publication of Le Valois’s text not only made it impossible for Pierre-Sylvain Régis to continue his public conferences on Cartesianism in Paris, but also delayed for 10 years the publication of his Système de philosophie. This work also led Louis-Paul du Vaucel to warn his fellow Jansenist Arnauld, in an unpublished “Observations sur Descartes” (1680), of the dangers of associating Jansenism too closely with a discredited Cartesianism.
LIGHT. Descartes devoted a great deal of effort to explaining the nature and behavior of light. Among the first triumphs of the new physics was a derivation, contemporary with Willebrord Snell’s, of the law of refraction (1620s; a version of it was published in the Dioptrics in 1637). Though the details of his theory of light vary from one work to another, one basic idea persists: light consists of pressure exerted by particles of the second or first element (Principles III, art. 55, 78, IV, art. 28). It results from the centrifugal force each such particle exerts according to the second law of motion. That pressure is created by the vortices around each major heavenly body, and is directed outward from the center of that body. It is probably stronger in the plane of rotation of the vortex (the equator) than at the poles.
Descartes insisted—indeed he made it an irrepudiable tenet in a 1634 letter to Isaac Beeckman—that light is transmitted instantaneously. The 1676 determination by Ole Christensen Rømer, using observations of the satellites of Jupiter, that the speed of light is finite, was thus a serious problem. It seems not to have been dealt with by later Cartesians (see Samuel Clarke’s notes to Jacques Rohault’s Physica, pp. 180, 186).
The importance of Descartes’s theory, however inadequate, was that it explained mechanistically some of the phenomena for which Aristotelian philosophy had supposed qualities (notably, light and color) distinct from the modes of extension.
LOGIC. Logic is the theory of inference, and in the tradition following Aristotle the subject was primarily concerned with the codification of valid forms of inference based on the form of the syllogism. Descartes would have learned the traditional logic of Aristotle at La Flèche, but he held the subject in little regard. In the Discourse on Method he remarks that “in the case of logic, its syllogisms and the greater part of its other lessons serve rather to explain to someone else the things one already knows,” and complains that, “although it contains, in effect, very true and good precepts, nevertheless there are so many others, mixed up with them, which are either harmful or superfluous, that it is almost as hard to separate the one from the other as to draw a Diana or a Minerva from a block of marble” (AT, vol. VI, p. 17). See also DEDUCTION; DEMONSTRATION.
LOUIS XIV (1638–1715). The self-proclaimed Sun King (Le Roi Soleil), who ruled France with the help of the First Minister Cardinal Marazin until the death of the latter in 1661, and who subsequently broke with tradition by ruling without a first minister until his death in 1715. Louis issued two decrees directed against Cartesianism, both of which concerned the University of Paris. The first decree, issued in 1671, enjoined university officials to enforce statutes prohibiting the teaching of anti-Aristotelian philosophy in order to prevent the airing of views that “could bring some confusion in the explanation of our mysteries.” This decree most likely was prompted not by the 1662 condemnation of Descartes in the University of Louvain, but rather the growing popularity of Cartesianism in France due primarily to the private conferences of the natural philosopher Jacques Rohault. This decree also was immediately preceded by the anonymous publication of the Considérations sur l’état présent of the French Cartesian Robert Desgabets, which Louis’s confessor Jean Ferrier condemned for denying the Catholic doctrine of transubstantiation. The condemnation of this work may well explain the reference in Louis’s decree to the confusion certain views bring to the explanation of the mysteries. In any event, the 1671 decree was invoked in various campaigns against Cartesians and Cartesianism in the 1670s at provincial colleges in Angers and Caen.
Louis’s second decree, issued in 1691, was a formulary signed by the Paris faculty of philosophy condemning the teaching of 11 propositions. The first three of these propositions concern a method of doubt in Descartes that questions even the existence and veracity of God, whereas the last four propositions concern various claims that impugn the necessity of absolute freedom for our responsibility for sin. The fact that the last set of propositions was drawn from official condemnations of the views of Cornelius Jansenius reveals an attempt in the formulary to link Cartesian philosophy to Jansenist theology.
Louis did not allow for unrestrained teaching of Cartesianism in the French universities and religious orders. However, he did allow his son, the dauphin, to be instructed in the fundamentals of Cartesianism by his tutors, one of whom included the Cartesian Gérauld de Cordemoy. Moreover, Louis did not take the option open to him of preventing the appointment of Cartesians Nicolas Malebranche and Pierre-Sylvain Régis to the Paris Académie des Sciences. Thus, one cannot speak of an unqualified opposition to Cartesianism on his part.
LOUVAIN, UNIVERSITY OF. A leading intellectual center of Catholic thought in the Spanish Netherlands (now Belgium). This institution is connected to Cartesianism principally through the 1662 condemnation of five theses from Descartes by its Faculty of Theology. These theses all concern aspects of Descartes’s metaphysical physics and cosmology. In particular, the theologians condemned Descartes’s denial of substantial forms other than the human soul, his denial of the real qualities purportedly required by the Catholic doctrine of the Eucharist, his assertion that extension is the “essential attribute” of body, his claim that the extension of the world is unbounded, and his rejection of the possibility of a plurality of worlds. The papal nuncio, Jérôme de Vecchi, pushed for the condemnation in order to counter the popularity of the new Cartesian philosophy among the members of the Faculties of the Arts and Medicine at Louvain. There is some evidence that Vecchi also was involved in the 1663 decision of members of the Roman curia to place a selection of Descartes’s writings on the Index librorum prohibitorum. These writings were still present in the final edition of the Index published in 1948.
LOVE (AMOR, AMOUR). Together with admiration, joy, sadness and desire, love and hatred are the fundamental or “primitive” passions for Descartes (Passions II, art. 69, AT, vol. XI, p. 380). Love is defined as “an emotion of the soul caused by the movement of the spirits, which incites it to readily join the objects that seem suitable to it” (Passions II, art. 79, AT, vol. XI, p. 387). Hatred, on the other hand, is “an emotion caused by the spirits, which incites the soul to want to be separated from the objects which present themselves to it as being damaging” (Passions II, art. 79, AT, vol. XI, p. 387). The definitions are not without their own difficulties because it seems difficult to distinguish love from desire, which almost invariably accompanies it. But the object of desire is in the future, whereas the object of love is the union with (or, in the case of hatred, the separation from) a particular being. Physically love (provided it is not accompanied by other passions) is characterized by an equal heartbeat, a sweet warmth in the breast, and a quick digestion, “which is the reason why this passion is good for health” (Passions II, art. 97, AT, vol. XI, p. 402). This is caused by a widening of the entrance to the heart, which allows the newly made blood to pass quickly into it, without remaining in the liver. Given the fact that this produces not only blood of a good and equal quality but also animal spirits that are quick and strong, this helps the mind to concentrate on the idea of the loved object. As in all passions the connection between love and its physical manifestations goes back to a form of conditioning in early youth, based on our first experience of being fed; for most people this was the first occurrence of a state they wished to retain and the reason why the same physiological phenomena come back whenever we wish to retain a certain condition.
In a letter to Pierre-Hector Chanut of February 1, 1647, Descartes completes this account by making a further distinction between passionate love (the type of love discussed so far) and intellectual (or rational) love. This is produced “when our soul perceives some good, whether present or absent, which it judges to be suitable for it, and wants to be united with that good.” Thus we can desire or enjoy science without having the bodily experiences that usually accompany love, joy, and desire. Accordingly, intellectual love could be in the soul even if it is not united with the body, although, as long as we are in fact united with the body, some form of passionate love usually accompanies intellectual love. A separate case is the love of God. The difference between God and us is so great that it is almost impossible to see us as forming a whole of which God and we are parts. Still, if we think of God as a mind, we may come to think of our own mind as some sort of emanation of God, without identifying ourselves with him or giving ourselves the idea that we could be gods. Indeed, the contemplation of nature gives us such an elevated idea of God’s infinity and almightiness that our greatest desire is that God’s will be done.
LOYOLA, IGNATIUS. See JESUITS.
LUYNES, LOUIS-CHARLES D’ALBERT, DUKE OF (1620–90). Louis-Charles d’Albert came from a noble family, whose Italian origins (originally they were called Alberti), go back to the 12th century. In 1639 he became Pair de France (“peer of the realm”). As a military officer he distinguished himself during the defense of Camp, near Arras, when the Spaniards attacked it on April 2, 1640, as well as on several other occasions. On September 23, 1641, he married Marie-Louise Séguier. She died on September 13, 1651, after giving birth to nine children, five of whom did not survive infancy. By papal dispensation he remarried in 1661, taking as his wife Anne de Rohan, a close cousin (his mother was a Rohan). She died in 1684, after giving birth to seven other children. His third marriage was with Marguerite d’Aligre, dowager of Charles-Bonaventure Marquis de Manneville. Luynes died in Paris on October 10, 1690. His son Charles-Honoré, born in 1646 out of his first marriage, became known as Duc de Chevreuse and was a famous military hero.
According to Adrien Baillet, Descartes knew of Luynes’s translation of the Meditations only in 1644, when it was already finished. Apparently, it had been undertaken by the young duke “to exercise his style on a great subject, without having in mind the service he brought to the public” (AT, vol. IV, p. 193). Descartes took it with him from Paris to Bretagne in the summer of 1644 and used this opportunity to correct the text in a few places. Although Claude Clerselier also made a translation, which moreover included the Objections and Replies, Descartes preferred the translation of the Duc de Luynes for the Meditations as such, undoubtedly also because of the high position of the translator. Nothing is known of any direct contacts between Descartes and Luynes, nor is it known in what way and by whom Descartes was informed of the existence of his translation.