Christian Wolff and Leibniz Charles A. Corr Journal of...
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Christian Wolff and Leibniz
Charles A. Corr
Journal of the History of Ideas, Vol. 36, No. 2. (Apr. - Jun., 1975), pp. 241-262.
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CHRISTIAN WOLFF AND LEIBNIZ
A recent article in this journal describes certain mathematical and philosophical controversies which occurred in Prussia during the mid- dle decades of the eighteenth century.' The article pays particular at- tention to the position of Christian Wolff and to the views of some of his followers. Both Wolff and the Wolffians are shown to have supported some of Leibniz's doctrines against those of the Newtonian camp. As a result, or perhaps in part as a premise, there is a strong tendency throughout the article to identify Wolff himself with Leibniz. The reader will naturally conclude that Wolff (and, in turn, the Wolffians) must have been a faithful student and expositor of his master, Leibniz. My purpose in the present investigation is to contribute to an exami- nation of the accuracy of this portrayal.
There is a long and venerable tradition which supports identification of the views of Wolff and Leibniz. Its strength rests principally on the pronouncements of several prominent German scholars of the last century, e.g., Windelband and Zeller.2 Their statements appear to have played a large role in determining Wolff's fate among more general his- torians and most contemporary historians of philosophy. The opinion typical of these writers is that Wolff simply rendered Leibniz's ideas in systematic form; also he is frequently accused of omitting key insights, or of missing the spirit of the whole.3
It is true that some scholars have hesitated to accept this dominant interpretation in its full force. What they say of Wolff ranges from ob- servations that he did not accept all of Leibniz's ideas or that he disagreed with Leibniz on several key points, to emphases on the variety of his sources and to a recognition that he contributed some ideas of his
'Ronald S. Calinger, "The Newtonian-Wolffian Controversy (1740-l759)," JHI, 30 (1969), 319-30; idem, "The Newtonian-Wolffian Confrontation in the St. Petersburg Academy of Sciences (1725- 1746)," Journal of World History, 1 1 (1968), 417-35.
T f . Wilhelm Windelband, Die Geschichte der neueren Philosophie in ihrem Zusam- menhange mit der allgemeinen Kultur und den besonderen Wissenschaften, 2 vols. (Leipzig, 1878), I, 496, and Eduard Zeller, Geschichte der deutschen Philosophie seit Leibniz (New York, 1965; originally Munich, 1873), 213. This interpretation may have been encouraged by Hegel's Lectures on the History of Philosophy, 3 vols., trans. E. S . Haldane and F. H. Simpson (New York, 1955), 111,348.
aTwo recent examples of this view: A. Robert Caponigri, A History of Western Philosophy, Vol. 111: Renaissance to the Romantic Age, 5 vols., with Ralph M. McInerny (Chicago, 1963), 429, and Etienne Gilson and Thomas Langan, Modern Philosophy: Descartes to Kant (New York, 1963), 172-73; also Peter Gay, The Enli~htenment:An Inter~retation (New York, 1967), 329.
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own.4 But it is obvious that these writers are not in complete agreement and have not mounted a sustained or very visible campaign. They have failed to win their case in the general scholarly community, and the view that Wolff depends almost wholly upon Leibniz still prevails.
Nevertheless, the recent appearance of many volumes of a new edition of Wolff's works, together with a number of critical studies and some other helpful material, makes it possible to reopen the topic of his relation to Le ibn i~ .~ Furthermore, for both historical and doctrinal reasons it seems desirable to explore this subject. The central historical concerns are the development of philosophy in Germany and the course of modern philosophy on the Continent from Descartes to Kant; the doctrinal implications bear on a number of basic issues in methodology, metaphysics, epistemology, and the attempt to do philosophy in systematic fashion. We cannot pursue all of these ramifications in the present article, nor can we pretend to define the connection between Wolff and Leibniz in any conclusive way. It will be sufficient for the pur- pose of this article to answer three basic questions: l ) Did Wolff state that he intended to establish a "Leibnizian-Wolffian" philosophy? 2) Were Wolff's early views and his general program for philosophy formed under the influence of Leibniz? and, most important, 3) Is the outcome of Wolff's work in the several areas of philosophy, and espe- cially in metaphysics, in substantial agreement with the doctrines of Leibniz?
1. Direct Testimony-Wolff's own statements on the relationship between his philosophical position and that of Leibniz are straightfor- ward and unambiguous. He denies that there is any such thing as a "Leibnizian-Wolffian" philosophy or that he ever intended to create such a phi l~sophy.~ Moreover, he points out that there was no thought of a Leibnizian philosophy when he first began to teach and write on philosophical questions during the years 1703-06. Wolff admits that he
4E.g., Friedrich Ueberweg, Grundriss der Geschichte der Philosophie, Dritter Teil: Die Philosophie der Neuzeit bis zum Ende des XVIII Jahrhunderts, 14th ed. (Basel/ Stuttgart, 1957), 448-49; Hans Wolff, Die Weltanschauung der deutschen Aufklarung in geschichtlicher Entwicklung, 2nd ed. (Bern, 1963), 100-01; and Frederick Copleston, A History of Philosophy, Vol. 6: W o l f to Kant (Garden City, 1964), 126-35. The sole extended study is Walther Arnsperger's monograph, Christian Wolffs Verhifltnis zu Leibniz (Weimar, 1897).
5The new edition of Wolff's Gesammelte Werke is being published by Georg Olms Verlag in Hildesheim. Over 50 volumes are expected to appear in two series covering Wolff's German and Latin writings. Unless otherwise indicated, all references in this article to Wolff's works are to this edition. Few of Wolff's works have been translated into English; for our purposes the most important are Logic, or Rational Thoughts on the Powers of the Human Understanding (London, 1770; originally 1713), and Pre-liminary Discourse on Philosophy in General, trans. R. J . Blackwell (New York, 1963; originally 1728).
6E.g., Christian Wolffs eigene Lebensbeschreibung, ed. H . Wuttke (Leipzig, 184 I), 140-42, and Ausflhrliche Nachricht von seinen eigenen Schriften (1726), "Vorrede."
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drew freely upon what he knew of Leibniz's ideas, as he did upon the ideas of others, but adds that this must be qualified by the limits of what he knew at that time about Leibniz's philosophical views. Finally, in a number of instances Wolff takes pains to note that he has not followed Leibniz on various points of doctrine or that he is in specific disagreement with some of Leibniz's positions. We might account for some of these statements by speculating that Wolff was a proud man who did not wish to be regarded as a mere compiler or popularizer of another man's ideas. In any case, there can be no doubt that, in the words of Harald HiJffding, "Wolff himself disliked to be considered a disciple of Leibniz."'
Wolff's testimony is partly offset by that of his followers, who fre- quently linked his views (and their own) with those of Leibniz. The very expression, "Leibnizian-Wolffian philosophy," seems to have been coined by one of these disciples, Georg Bernhard Bilfinger (1693- 1750).8 In addition, Wolff's theological and philosophical opponents often employed a kind of broadside attack against him which involved coupling his doctrines with those of Leibniz. Thus Wolff's expulsion from Prussia in 1723 came about, at least in part, as the result of academic and political machinations which depended on the charge that he was teaching Leibnizian determinism and the destruction of free will.g Nevertheless, these same opponents also attacked Wolff for his supposed agreement with Spinoza, atheists, and other familiar disreputables who cannot all be said to be Leibnizians. As a result, their testimony is less than decisive. Indeed, the polemical quality of most of these statements and the fact that they originate, for the most part, with manual-writers and others of modest stature, rather than with in- dependent, critical thinkers, suggests that little can be gained by pursuing this line of inquiry. In short, the issue cannot be resolved on the basis of formal testimony alone. We need to look at circumstantial evidence and at the Wolffian texts themselves.
2. Circumstantial Data-The circumstantial evidence which bears on the links between Leibniz and Wolff may be conveniently divided into
'Harald Hoffding, A History of Modern Philosophy, 2 vols., trans. B. E. Meyer (New York, 1955), I, 369.
8Bilfinger (whose name is spelled variously) is best known for his Dilucidationes philosophicae de Deo, anima hurnana, mundo, et generalibus rerurn affectionibus (1725). In a letter to Count Manteuffel of May 1 1 , 1746, Wolff charges that "Biilffinger, who first came up with the 'Leibnizian-Wolffian philosophy,' caused the confusion." See Heinrich Ostertag, Der philosophische Gehalt des Wolff-Manteuffelschen Briefwech- sels (Leipzig, 1910), 60. The key phrase appears in the titles of Georg V. Hartmann, Anleitung zur Historie der Leibnitzisch- Wolfischen Philosophie (Frankfurt & Leipzig, 1737), and Carl G. Ludovici, Neueste Merkwiirdigkeiten der Leibnitz- Wolfischen Weltweisheit (Frankfurt & Leipzig, 1738).
gEduard Zeller, "Wolff's Vertreibung aus Halle; der Kampf des Pietismus mit der Philosophie," Preussische Jahrbiicher, 10 (1862), 47-72; reprinted in Zeller, Vortrage und Abhandlungen, ErsteSamrnlung, 2nd ed. (Leipzig, 1875), 117-52.
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three parts. The first concerns the period of Wolff's early intellectual formation up to the completion of his degree in 1703. His teachers during this time and the sources he studied define the basic directions of his academic career and the fundamental characteristics of his program for philosophy. The next part bears on the general position of Leibniz in German philosophic and intellectual circles during the opening decades of the eighteenth century. Just what sort of force did Leibniz exert and how much was known by the academic community concerning his philosophical views during the years from 1700 to the time of his death (1716) or shortly thereafter? Finally, we may ask about Wolff's direct contact with Leibniz, which seems to have begun in 1704. Knowledge of the nature of this relationship and of the extent to which Wolff was familiar with Leibniz's views will help us to understand whether, and to what degree, Wolff may be said to be Leibniz's disciple.
Virtually all who are acquainted with the biographical data agree that Leibniz played little, if any, role in Wolff's formal education.1° Wolff's education began in the Mary Magdalen School in Breslau. His original intention, in accordance with his father's wishes, was to study theology in preparation for the ministry. In addition, he applied himself to mathematics and philosophy. His teachers included Gryphius, who ridiculed philosophy, and Pohl and Neumann, who criticized the errors of the Scholastics but kindled in their pupil a desire to learn more about Cartesian philosophy. Breslau also possessed a sizable Catholic popu- lation and a school run by the Jesuits. Wolff took advantage of this to familiarize himself with Catholic philosophy and theology, although he did not then think much of the Scholastic philosophy.
In 1699 Wolff moved to the University of Jena.ll He felt himself to be already well prepared in theology, and therefore emphasized other studies. In particular he was able to pursue, under Professor Hamberger, his interest in mathematics and physics. This interest in mathematics was spurred by a desire to overcome the endless polemics which dominated philosophy and theology. Wolff sought to reconcile di- vergent factions and establish the principles of a secure religious and moral life by emulating the mathematicians. His hope was to learn the secret of the mathematical method and then apply it to philosophy and theology, to bring them to the certainty they so obviously lacked. Contemporary advances in disciplines such as optics and astronomy appeared to give support to this program by showing that the mathematical method could be applied in other areas.
1°Esp. H. J. de Vleeschauwer, "La genbse de la mCthode mathkmatique de Wolf. Contribution h l'histoire des id& au XVIIIe si&cle," Revue Belge de philologie et d'histoire, 1 1 (1932), 651-77.
lLOn Wolff and the contemporary German academic milieu: Max Wundt, Die Philosophie an der Universitdt Jena (Jena, 1932).
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In general, we may say that during the period of Wolff's education at Breslau and Jena he was able to draw on three principal sources: the writings of the Cartesians, including Tschirnhaus; Aristotelian school philosophy (both Protestant and Catholic); and the emerging empirical methods of Newtonian science.12 Wolff was a good student and read widely, but it is not likely that he was directly acquainted with primary sources which go back much further than the previous hundred years. Thus, by 1703 Christian Wolff was very much a man of his times, espousing a thoroughly Cartesian program for philosophy. He seems to have been little influenced by Leibniz during this period, and in at least one case he says that he associated what he knew of Leibniz's views with the school philosophy, which he held in low esteem.13
Since we have not found Leibniz playing a part of any significance in Wolff's formal education, we may well ask just what his position was at the outset of the eighteenth century. Many things are relevant to deter- mining Leibniz's influence on German academic circles of this time, but perhaps the most important for our purpose are the schedule and the nature of his publications. In terms of published work, the Leibniz we know now is quite a different figure from the man his contemporaries mourned in 1716. At the time of his death Leibniz had published only one full-length book, the Essays on Theodicy (1710). A German translation of the Monadology appeared in 1720, but the French original was not published until 1840. Similarly, the New Essays Con- cerning the Human Understanding (completed in 1704) did not come into print until 1765, nor did the Discourse on Metaphysics (1686) until
121n his Deutsches Geistesleben zwischen Reformation und Aufklarung: Von Martin Opitz zu Christian Wolff, 2nd ed. (Frankfurt, 1956), esp. 194222, Herbert Schaffler offers a slightly different trilogy of stimulating sources: the Lutheran, the Catholic, and the Cartesian or west-European (which includes a strain of empiricism from England). The English influence is pursued by Gustav Zart, Einj?uss der eng- lischen Philosophen seit Bacon auf die deutsche Philosophie des 18. Jahrhunderts (Berlin, 1881), esp. 17-30. On Tschirnhaus: Lewis White Beck, Early German Philosophy: Kant and His Predecessors (Cambridge, Mass., 1969), 189-94. The problem and much of the available literature concerning the tangled web of the school philosophies of the 17th and 18th centuries is surveyed by JosC Ferrater Mora, "Suhrez and Modern Philosophy," JHZ, 14 (1953), 528-47. For our purposes the most im- portant of the works which deal with this topic is Max Wundt, Die deutsche Schulphi- Iosophie im Zeitalter der ~ u f k l h . r u n ~ (Hildesheim, 1964; originally Tiibingen, 1945), esp. 122-99. In this regard, it is interesting to note that Wolff himself claims that "all things considered, it is not correct that I have brought the Leibnizian philosophy into a distinct system, since very little that is found in my Verniinftige Gedanken von Gott der Welt . . . belongs to Leibniz; quite a few controversial things are taken from St. Thomas rather than from Leibniz." Wolff's Gesammelte kleine philosophische Schrifften, 6 vols., ed. G. F. Hagen (Halle, 1736-40), IV, B, 269; the text is a German translation of one of Wolff's minor works published in 1723, during the quarrel with his theological opponents.
13Christian Wolffs eiaene Lebensbeschreibuna. 116, n.1.
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1846. The Dissertation on the Art of Combination had been published in 1666, but on the whole the learned world knew of Leibniz's views largely through a series of occasional articles published between 1686 and 17 16 in such journals as the Acta eruditorum and the Journal des scavans. l4 In addition, a number of his ideas were promulgated through letters to selected correspondents; but this is hardly a very public method of communication. In a word, most of Leibniz's philosophical writing existed in the form of incidental papers, outline sketches, unpublished manuscripts, and private correspondence; hence his own statement that "he who knows only what I have published does not know me."15
None of this should be taken to imply that Leibniz was not an im- portant political figure and intellectual force during the period in ques- tion. His association first with the Elector of Mainz and later with the House of Brunswick as adviser, diplomat, historian, and librarian gave him a position of influence from which to pursue his varied interests. Along with others, he founded the first learned journal in Germany, the Acta eruditorum Lipsiensium (1682), as well as the Prussian Academy of Science at Berlin (1700), which he served as first (lifetime) president. Leibniz was widely acquainted with the leading European scientific and intellectual figures of his time. In addition to philosophy and mathematics, his interests touched on the wisdom of the Orient, on ecumenical reconciliation, and on a plethora of other subjects. There can be no doubt of his stature in the ten or fifteen years before his death; the question which remains open is the extent to which his central philosophic doctrines were known to the scholarly public, and to Wolff in particular.
Wolff came into direct contact with Leibniz through the in- tercession of Otto Mencke, the editor of the Acta eruditorum. Al-though Wolff had studied at Jena and actually wrote his dissertation there, he was examined for the master's degree at the University of Leipzig and submitted his thesis to the latter university. As professor of moral philosophy at Leipzig, Mencke was the principal reader of this dissertation, De philosophia practica universalis mathernatica methodo conscripta. Mencke's evaluation of Wolff's work was so favorable that he not only approved the conferral of Wolff's degree, but also drew him
14Anton Bissinger has sketched the main papers and ideas of Leibniz which were available to Wolff both through Leibniz's publications and through the correspondence between the two men; Die Struktur der Gotteserkenntnis: Studien zur Philosophie Christian Wolfs (Bonn, 1970), 21-24.
15This oft-quoted statement is from a letter of 1696 to Vincent Placcius in Got. Guil. Leibnitii . . . Opera omnia, 6 vols., ed. L. Dutens (Geneva, 1768), VI, i, 65. Ernst Cassirer acknowledges the imperfect, exoteric knowledge which the eighteenth century had of the philosophy of Leibniz, and concludes that "the influence of Leibnizian ideas is therefore indirect, namely, by way of the transformation they underwent in the system of Wolff" (my italics); The Philosophy of the Enlightenment, trans. F . Koelln and J. Pettegrove (Boston, 1955), 33-34.
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into the work of the journal as a reviewer and contributor. In addition, apparently without Wolff's knowledge, Mencke sent the dissertation to Leibniz, and he advised the young man to do the same with another treatise on algebra. Both of these pieces were concerned with mathematical method: the treatise on algebra dealt with the topic directly and advocated the position of Descartes and Tschirnhaus that the syllogism is not a means of discovering truth, while the other work applied the techniques and trappings of a geometry treatise to the topic of universal practical philosophy.
Leibniz was impressed and responded very favorably to Wolff's work, although he indicated that he did not share Wolff's negative view of the syllogism. Three things followed. First, Wolff reexamined his position on the syllogism and completely reversed his early evalua- tion.16 He concluded, not only that the syllogism was a legitimate means to discover new knowledge, but that it was the essential element behind mathematics, science, and ordinary modes of thought. Nothing else is so typical of Wolff's mature writings as their thoroughgoing commitment, both in theory and in practice, to the machinery of the categorical syllogism. Leibniz was certainly the critical influence in re- versing Wolff's early "prejudice" against the syllogism, but one won- ders if he would have looked favorably upon the equally exclusive position which resulted.
Second, Wolff's contact with Leibniz led to an exchange of letters between the two men. C. I. Gerhardt has published 97 of these letters (some only in extract form) from a total of 127.l7 They are largely de- voted to mathematics, the natural sciences, and some personal mat-
16Wolff comments on his early evaluation of the syllogism and on the influence of Tschirnhaus and Leibniz in correcting "this prejudice" in his Ratio praelecfionum (1718), Sec. 11, Ch. 2, ##5-27 (pp. 12g30). Cf. C. I.Gerhardt's edition of the Briefwechsel zwischen Leibniz und Christian Wolff (Hildesheim, 1963; originally Halle, 1860), 18, for the crucial letter of February 21, 1705, in which Leibniz told Wolff, "I would not venture to say absolutely that the syllogism is not a means of discovering truth." On method in WolE Giorgio Tonelli, "Der Streit uber die mathematische Methode in der Philosophie in der ersten Hllfte des 18. Jahrhunderts und die Ent- stehung von Kants Schrift uber die 'Deutlichkeit'," Archiv ftlr Philosophie, 9 (1959), 37-66, and Nicolao Merker, "Cristiano Wolff e la metodologia del razionalismo," Rivista crifica di sforia dellafilosofia, 22 (1967), 27 1-93; 23 (1968), 21-38.
17Gerhardt,Briefwechsef. Arnsperger (op. cit., 66-72) provides a chronological list of the entire correspondence. He also notes (22, 33) that the two men only met three times, a t Berlin in 1706 and a t Halle'in 1713 and 1716. During the first of these visits, Wolff was shown the manuscript for the Theodicy, although he later complained in a letter to Manteuffel (Dec. 13, 1743) that "Iwas not able to read through Leibniz's Theodicy completely, rather I only paged through it casually, although I wrote a review of it in the Acta by picking out for myself what belonged to the subject, and in so doing I gave him his due." This passage is reproduced by Wuttke (83), Gerhardt (12-13), and Arnsperger (4). Wundt observes (Die deutsche Schulphilosophie im Zeifalter der Auf klarung, p. 135, n. 1) that there is no mention of Wolff's Deutsche Logik (publ. 1713) in the correspondence between the two men, rather a strange omission since this is Wolff's only major philosophical publication prior to Leibniz's death.
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ters, although Leibniz does discuss some of his philosophical ideas- most notably, the doctrine of preestablished harmony-in response to Wolff's inquiries. This tends to support Wolff's statement that he had no privileged access to Leibniz's philosophical insights. Leibniz corre- sponded with a wide variety of people in a similar way, and the 47 let- ters which he addressed to Wolff are not distinguished by their depth or frequency.
In a letter to another correspondent, Leibniz describes Wolff's position in the following way: "Mr. Wolff has agreed with some of my sentiments, but since he is very busy with teaching, especially mathematics, and we have not had much communication concerning philosophy, he can hardly know more of my opinions than those which I have published."18 This comment has a two-fold significance. It clearly indicates that Wolff was not a member of any kind of inner circle of initiates who knew Leibniz's thought more intimately than did the general public. Still, it is also obvious that Leibniz regarded Wolff as one who is at least partly sympathetic to his own views. Our interest lies in the origin and extent of this sympathy and in the degree to which it leads to doctrinal identity on specific issues. The reference to Wolff's concentration on mathematics is consistent with our knowledge of his duties and interests, always remembering that Wolff regarded mathematics as a means to other ends. Leibniz seems not to have ap- preciated the extent to which Wolff was committed to philosophy, for Wolff complains that Leibniz desired that he should devote himself completely to mathematics. As a result Wolff says, "I did not like to correspond with him concerning his phil~sophy."'~ With the exception of his German treatise on logic (1713), Wolff's major philosophical publications did not appear until after Leibniz's death, and it seems fair to say that Leibniz may have been unaware of the philosophical ferment in his young correspondent's mind during the twelve years of their ex- changes.
The third consequence of Wolff's introduction to Leibniz is sym- bolized more by the existence of their correspondence than by its content. A kind of mutual respect, if not warm friendship, developed. Neither man seems to have fully opened his heart or mind to the other, but they did become implicated in each other's lives. One immediate re- sult was that Leibniz gave Wolff some practical assistance in advancing his career. Wolff had been unable to obtain a permanent position at Leipzig because of certain regulations concerning the geographical srigins of faculty members. In 1706 Leibniz interceded on Wolff's be-
l8This statement is from a letter to Remond or Pierre de Montmort, July 1714,in C. I. Gerhardt's edition of Die philosophischen Schriften von Gottfried Wilhelm Leibniz, 7vols. (Hildesheim, 1960-61;originally Berlin, 1875-90), 111,619.
'OChristian Wol fs eigene Lebensbeschreibung, 142.
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half to obtain a post for him at the twelve-year-old University of Halle.20 This was not the only occasion when Leibniz's influence or advice aided Wolff, but it was easily the most important. Halle, a young, vital institution dominated philosophically by Christian Thom- asius, lacked a professor of mat he ma tic^.^' Though not wholly hos- pitable to Wolff's interests-and later on the scene both of his great clash with the Pietistic theologians and his eventual triumphant return-Halle was a place to which Wolff could readily adapt. It allowed him to further his knowledge of mathematics before gradually shifting to the experimental sciences and philosophy, and it was the place of his early rise to fame.
Further evidence of the practical effects of Wolff's contact with Leibniz may be seen in the fact that it was Wolff who wrote the eulogy of Leibniz in the Acta eruditorum. 22 Wolff also took part in some of the conflicts with the Newtonians and wrote prefaces for at least three posthumous editions of papers by LeibnkZ3 Moreover, in 1736 Count von Manteuffel founded a society for the lovers of truth ("Societas Alethophilorum") and commissioned a medal depicting the visages of Leibniz and Wolff divided by Minerva and the inscription "sapere aude." In short, Wolff was associated with Leibniz in a number of ways, although he had little acquaintance with Leibniz prior to 1704 and no important privileged knowledge of Leibniz's philosophical views during later years.
3. Doctrinal Comparisons-The effect of our analysis of the direct testimony and the circumstantial evidence bearing on the connection between Leibniz and Wolff is to show that we must examine the doc- trinal positions of the two men if we are to come to a satisfactory understanding of their relationship. Such an examination is restricted
20Wolff's request for assistance and Leibniz's letters of recommendation are in J. C. Gottsched, Historische Lobschrift des weiland hoch- und wohl-gebornen Herrn Chris- tians des H. R. R. Freyherrn von Wolf(Halle, 1755), Beylagen, 4-5. Wolff's letter is also in Gerhardt, Briefwechsel, 60-6 1.
21Wilhelm Schrader, Geschichte der Friedrichs-Universitdt zu Halle, 2 vols. (Berlin, 1894), esp. I, 168-8 1, 21 1-19, 316-26, and Friedrich Paulsen, The German Universities and University Study, trans. F . Thilly and W. W. Elwang (New York, 1906), 42-49.
22"Elogi~mGodofreid Guilielmi Leibnitii," Acta eruditorum (July 17 17), 322-36. A German translation is in Wolff, Gesammelte kleine philosophische Schrifften IV, A, 449-502.
23For the conflicts with the Newtonians: Calinger, art. cit., and H. J . de Vleeschauwer, "Christian Wolff et le Journal IittCraire. Contribution A la controverse Leibniz-Newton au sujet du Calcul differentiel," Philosophia naturalis, 2 (1953), 358- 75. Wolff's prefaces are cited in the Leibniz-Bibliographie: Verzeichnis der Literatur fiber Leibniz, ed. Kurt M u k r (Frankfurt, 1967), ##557, 560, 2625. They introduce a German edition of the Leibniz-Clarke correspondence (1720), a collection of brief philosophical papers (1740), and a treatise on jurisprudence (1748). The first of these prefaces is reprinted in Wolff, Gesammelte kleine philosophische Schriyten, 111, 27 1- 96.
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by the limits of space and by the lack of a conclusive interpretation of the positions which form the two poles of this relationship. Although the central outlines of Leibniz's thought are firmly established, some important controversies still continue and much unpublished material has yet to be fully studied. The situation with respect to Wolff is still more difficult. A good deal of study and discussion will have to take place before we become familiar with Wolff's thought in all of its nuances and implications. For this reason principally, it is not now possible to make a definitive comparison of the doctrines of Wolff and Leibniz. Nevertheless, some typical examples can be given which may serve as a guide to further study. In this article we shall consider representative doctrines from the areas of Wolff's program for philosophy, his methodology, and his metaphysics. In each case em- phasis will be placed on doctrines which seem to distinguish Wolff's thought from Leibniz's.
a) A Program for Philosophy. Wolff set out, like Descartes, to overcome the sterility of the philosophy of his time and to reestablish philosophy as a sound body of disciplined knowledge. To begin, he di- vides all human knowledge into history (which deals with the fact), philosophy (which seeks the reason of the fact), and mathematics (which determines the quantity of the fact).24 History provides the expe- riential data, mathematics supplies the method and an example of systematic order, and philosophy unites the two in a holy marriage of reason and experience. Wolff defines philosophy itself as "the science of the possibles insofar as they can be."2s This means that the philosopher is obligated to give reasons which explain why things or events are possible, as well as why they actually are. As a body of necessary scientific knowledge, philosophy concentrates on demonstration on the level of possibility, but Wolff's ultimate intention is to bring his philosophy to bear on the elucidation of real existents. Since these con-
24Cf. Christian Wolff, Discursus praeliminaris de philosophia in genere, ##3, 6, 14 (pp. 3, 4, 8), for the definitions of these modes of knowledge, and #17n (p. lo), for an example which illustrates their relationships. This important treatise appears as a preface to Wolff, Philosophia rationalis sive Logica (Verona, 1779; originally Frankfurt & Leipzig, 1728); English quotations and page references are from the translation by R. J. Blackwell (op. cit.). Cf. Blackwell's "The Structure of Wolffian Philosophy," The Modern Schoolman, 38 (1961), 203-18. The only comprehensive study of Wolff's thought is Mariano Campo, Cristiano Wolfle il razionalismoprecritico, 2 vols. (Milan, 1939).
2 5 D i s ~ ~ r s ~ spraeliminaris, #29 (p. 17). In the note to this paragraph Wolff says that he conceived this definition in 1703, discussed it in some private correspondence in 1705, and published it in 1709 in the preface to the Elementa aerometriae. He adds that it guided all of his philosophizing since that time. A German translation of the 1709 preface is in the Gesammelte kleinephilosophische Schrtyten, 1I,3-21. For an analysis of this definition of philosophy: Hans Luthje, "Christian Wolffs Philosophiebegriff," Kantstudien, 30 (1925), 39-66.
CHRISTIAN WOLFF AND LEIBNIZ 25 1
cerns and a common method apply throughout philosophy, its several parts are distinguished primarily by the subjects they consider. The principal division in Wolff's schema of the parts of philosophy is be- tween the theoretical disciplines and those which deal with human ac- tions. The former comprise metaphysics-consisting, in order, of ontology, general or transcendental cosmology, psychology, and natural the~logy~~--and physics, with its many subdivisions. The sciences that consider human actions include those parts of philosophy that deal with the cognitive actions of man (logic and the ars inveniendi or art of discovery), the appetitive (the various parts of practical or moral and social philosophy), and the productive.
Two themes distinguish this Wolffian program for philosophy: 1) its explicit concern to raise philosophy to the level of a scientific system; and 2) the stress on the orientation of theoretical knowledge to practical utility. The first point is illustrated in the careful way in which Wolff lays out the orderly relationships between the various parts of philosophy and between philosophy and other modes of knowledge. In addition, the system is bound together by a common logical method to be discussed in the following ~ection.~' I t is not enough to say that Wolff actually constructed a system of philosophy of a kind only latent in
26Tobe precise, this is the order set forth in the Discursus praeliminaris (##96-99; pp. 49-51) and followed by the succeeding six volumes in Wolff's Latin publications. Earlier in the Verniinfltige Gedancken von Gott, der Welt und der Seele des Menschen, auch allen Dingen iiberhaupt, the so-called Deutsche Metaphysik (Frankfurt & Leipzig, 1720), the order of the chapters (apart from the brief, introductory chapter) was ontology, empirical psychology, general cosmology, rational psychology, and natural theology. Wolff gives credit to his student, Ludwig Philipp Thummig (1697-1728), for having led him to the improved order of the later works. Ausflhrliche Nachricht, Ch. 7, #79 (pp. 23&32), refers to Thummig's Institutiones philosophiae Wol'anae, 2 vols. (Frankfurt & Leipzig, 1725-26), "Prolegomena," ##2-4. In his Deutsche Metaphysik, a book of less than 700 octavo pages, Wolff dealt with a subject which later required six large quarto volumes in his Latin series. In view of the limited scope of this article, the analysis in the text follows the Latin works since they offer the mature and more detailed statement of Wolff's views. Parallel passages in the German volume can easily be located by the reader who wishes to examine the earlier expression of Wolff's metaphysics.
27Hence the ubiquitous prefix, "Vernunftige Gedanken von," to many of Wolff's German volumes, and the common subtitle, "methodo scientifica pertractata," for the later Latin treatises. The concluding phrase in the title of the Latin ontology volume ("qua omnis cognitionis humanae principia continentur") and the title of the corre- sponding section (Ch. 2) of the Deutsche Metaphysik ("Von den ersten Griiriden un- serer Erkantnis und allen Dingen iiberhaupt") show clearly that Wolff intended to combine a comprehensive science of knowledge and reality in this discipline. G. Kahl- Furthman has recognized this point in his "Inwiefern kann man Wolffs Ontologie eine Transzendentalphilosophie nennen?'Studia philosophica, 9 (1949), 8&92. Since Wolff's system lacks a distinct theory of knowledge, he is in a sense constrained to em- phasize the fundamental place of ontology (and, in turn, of metaphysics) among the other philosophical disciplines.
252 CHARLES A. CORR
Leibniz's thought, though that is certainly a genuine difference between the two men. Rather, it is the very sense of the term "system" that is at issue here. Thus, one scholar has suggested that Wolff's understanding of the term embraces both an opinion, hypothesis, or scientific mode of thinking in relationship to .a specific doctrinal complex (a wissenschaft- liche Denkungsart) and an organic, architectonic structure of dis- ciplines (a LehrgebZi~de).~~ Wolff recognizes the former sense of "system" in Leibniz when he speaks, for example, of the "system of pre-established harmony." Nevertheless, for Wolff, Leibniz has failed to integrate his ideas in the larger sense of "system" and has not offered the basic insights or the methodic apparatus that would make this task feasible.
Second, although Wolff's system is overtly dominated by its proxi- mate goal of achieving certitudinal knowledge, certitude is not prized as an end in itself.28 Rather, certitude is sought as a means to practical wisdom. Philosophy is both Wissenschaft and Weltweisheit, but it is the former for the sake of the latter. Wolff never tires of reminding his readers of the utility of his doctrines, both for furthering progress in the sciences and for the conduct of everyday life. This may help to explain why Wolff wrote both his dissertation and many later volumes-in German as well as in Latin-on moral philosophy, and why the prefaces to many of his books emphasize the link between under- standing, virtue, happiness, and the glory of God.
b) Methodology and Logic. We have already touched on Wolff's methodology in our discussion of his education, his early corre-spondence with Leibniz, and his program for philosophy. In terms of logic itself, it has recently been argued that Wolff did not follow Leibniz in at least two key doctrines, the theory of irreducible simple elements
28This distinction is developed by Walter Arnsperger (op. cit., 43-44). Wolff com- ments on his notion of system in the Ausfihrliche Nachricht (esp., Ch. 4, #34; p. 109) and in a short paper, "De differentia intellectus systematici & non systematici," which originally appeared in his Horae subsecivae Marburgenses (the so-called Marburg Nebenstuden; Frankfurt & Leipzig, 1729), 107-54. A German translation of the latter is in the Gesammelte kleine philosophische Schr imn, IV, A, 163-219. Note that system requires both the proper form of proof and true principles or material elements. Euclid is cited as an example of a writer who respected these requirements, while Spinoza is mentioned as a well-known violator of the latter component.
28See my "Certitude and Utility in the Philosophy of Christian Wolff," Southwes-tern Journal of Philosophy, 1 (1970), 133-42, and Lewis White Beck, Early German Philosophy, 261. Kuno Fischer, Gottfried Wilhelm Leibniz: Leben, Werke und Lehre, 5th ed. (Heidelberg, 1920), 619, takes this as the decisive point of difference between Leibniz and Wolff. One striking way in which Wolff expressed his practical concern was in his use of the vernacular both for teaching and writing. Leibniz called for the use of German; Wolff accomplished the task: Eric A. Blackall, The Emergence of German as a Literary Language, 1700-1775 (Cambridge, 1959), esp. 26-48.
CHRISTIAN WOLFF AND LEIBNIZ 253
and the so-called predicate-in-notion principle.30 Wolff mentions the theoretical possibility of carrying a conceptual analysis through to the point of irreducible or unanalyzable elements (no tiones irresolu biles), but he does not seem to pay much attention to this claim and he ap- parently did not develop a theory of such simple elements. Further- more, although he does consider identical propositions in his logic, he does not claim that every true proposition takes this form and he avoids the "praedicatum inest subjecto" phraseology. He seems to believe that the link between subject and predicate is based on an ontological con- nection between the essential constituents or determinations of a thing and one or more of its marks or characteristics, rather than on a rela- tionship of logical entailment or identity. These differences depend upon some metaphysical disagreements which will be noted below, and upon Wolff's emphasis, which has already been mentioned, on logic as a practical instrument for human reasoning.
Perhaps the most characteristic mark of Wolff's logic, however, and his most decisive break with the Cartesian tradition, is his thoroughgoing commitment to the principles and practice of the cate- gorical syllogism. Although he had come to appreciate the natural ordi- nation of the human mind to certitude by reflecting on mathematical method, Wolff eventually concluded that the rules of the syllogism were the best way to formalize the procedures of mathematics, science, and ordinary thinking.31 Apart from his undeveloped notion of an art of dis- covery, which is meant to supplement the syllogism in discovering new
30The argument is developed by Winfried Lenders in Die analytische Begrrfls-und Urteilstheorie von G . W . Leibniz und Chr. W o l f (Hildesheim, 1971), and summarized in "The Analytic Logic of G. W. Leibniz und Chr. Wolff: A Problem in Kant Re- search," Synthese, 23 (1971), 147-53. The central theses were first proposed by Gott- fried Martin; esp. the appendix to the second edition of Martin's Leibniz: Logik und Metaphysik (Berlin, 1967), 211-31. Lewis White Beck compares the positions of Leibniz, Wolff, and Kant on the question of judgment in "Lovejoy as a Critic of Kant," JHI, 33 (1972), esp. 476-78, and Wilhelm Risse offers a good general survey of Wolff's logic in Die Logik der Neuzeit, Bd. 11: 1640-1780 (StuttgartIBad Cannstatt, 1970), esp. 579-659. Hans Werner Arndt opposes the MartinILenders interpretation in his Methodo scientificapertractatum (Berlin, 197 l), 125-47.
Verniinffige Gedanken von den Kriiften des menschlichen Verstandes und ihrem richtigen Gebrauche in Erkenntnis der Wahrheit (1713), Ch. 4, #20 (p. 171): "By these syllogisms everything is found out that can be discovered by human understanding, and everything is proven to others that they want to be convinced of, although neither in dis- covering nor in demonstrating do we always have the form of the syllogisms distinctly before our eyes." The identification of reasoning and the syllogism is exhibited in their definitions in the Philosophia rationalis sive Logica. ##50, 332 (pp. 74, 159). For a dis- cussion of these themes, together with the "art of discovery": Hans Werner Arndt, "Christian Wolffs Stellung zur 'ars characteristica combinatoria'," Filosoja, 16 (1965), 743-52, and my "Christian Wolff's Treatment of Scientific Discovery," Journal of the History of Philosophy, 10 (1972), 323-34.
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truth, Wolff insists that his syllogistic logic is sufficient to provide theoretical justification for induction, immediate inferences, hy-pothetical reasoning, acts of faith, and all other human thought processes. As a result, he displays little interest in the sharp division be-tween analysis and synthesis or in the anticipations of symbolic logic which are found in Leibniz.
C) Ontology. According to Wolff, "ontology, or first philosophy, is defined as the science of being in general, or insofar as it is being."32 Ontology is properly called "first philosophy" because of its systematic primacy in metaphysics, and because metaphysics is first in the order of demonstration among the remaining parts of Wolff's philosophy. That is, Wolff conceives metaphysics as the solid foundation rather than the capstone of his philosophical system, and ontology is the base of that foundation. With this in mind Wolff pays special attention to the nature and order of the principles from which his ontology begins. Two central axioms govern the whole enterprise, applying equally to the order of being and to that of knowing. They are the principle of contradiction and the principle of sufficient reason.33 Through an examination of fa- miliar experiences of judging, Wolff claims to show that each of these principles involves both logical and ontological necessity. The former concerns intrinsic possibility or lack of self-contradiction, while the lat- ter deals with extrinsic possibility or actuality. Perhaps the most striking aspect of Wolff's treatment of these two principles is the ex- plicit subordination of sufficient reason to contradiction. The deduction of the former from the latter exactly reverses Leibniz's priorities and illustrates the strict systematic character of Wolff's philosophy.
Wolff's analysis of the structure of being depends on three principal components: "essentialia," "attributes," and "modes." "Essentialia" are the ultimate factors within a being, characterized by their lack of mutual determination and contradiction. The other constant factors in being, the attributes, depend on "essentialia" to explain both their possibility and actuality. The modes or variable elements of a being
32Philosophia prima sive Ontologia (1730), #1 (p. 1). Cf. Jean 6cole, "La Philo-sophia prima sive Ontologia de Christian WolR histoire, doctrine et mtthode," Giornale di rnetafsica. 16 (1961), 11425, and, more generally, Jost Ferrater Mora, "On the Early History of 'Ontology'," Philosophy and Phenomenological Research, 24 (1963-64), 36-47. &ole says of Wolff's role with respect to ontology that "in spite of the fact that he was not the creator, he can rightly be considered its reformer and reno- vator . . . . Wolff has given it a status both broader and firmer" (1 17). This article and those which follow in the same journal are largely taken from ficole's introductions to his edition of Wolff's texts.
33For an analysis of these principles: John E. Gurr, The Principle of Suficient Reason in Some Scholastic Systems: 1750-1900 (Milwaukee, 1959), 31-49, and Hans Pichler, Ueber Christian Wolfs Ontologie (Leipzig, 19 lo), 6- 19.
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must be compatible with its "essentialia," but their actual presence de- pends on the influence of external factors such as circumstances and other agents. The remainder of Wolff's ontology may be summed up in three points which highlight this analysis: 1) existence is described as the "complement of possibility," which means that it is understood as a variable mode of being; 2 ) substance is defined as "an endurable and modifiable subject"; and 3) the entire treatment is notable for its failure to include the language or the doctrine of monads.34
d) General Cosmology. Wolff claims that his general cosmology is unique in two respects: first, in its organization as a comprehensive, systematic discipline, and second, in its character as a part of metaphysics. For the latter, Wolff initiates a distinction between "cosmology" and "general" or "transcendental cosmology." The former is defined as "that part of physics which treats of the total bodies of the world and which teaches how the world is composed from them . . . the science of the world as such," while the latter is "a general understanding of the world which explains those things which are com- mon to the existing world and to any other possible world . . . the science of the world in general."35 Despite these claims to uniqueness, when one reads the General Cosmology it is clear that "the main lines of the vision of the world and of bodies are exactly the same in Wolff and in L e i b n i ~ . " ~ ~ Both the world and the bodies in it are said to be constituted by the interconnection of simpler entities. The modes of interaction among these beings allow for spatial, temporal, and causal
a4Cf.Philosophiaprima sive Ontologia, ## 134, 174,768 (pp. 115, 143, 574), respec- tively, for the pivotal definitions of being, existence, and substance. These topics are examined in Julius Bergmann, "Wolffs Lehre vom Complementum possibilitatis," Ar-chiv fur systematische Philosophie, 2 (1896), 449-76; Anneliese Michaelis, Der ontologische Sinn des Complementum Possibilitatis bei Christian Wolf(Berlin, 1937); Etienne Gilson, Being and Some Philosophers, 2nd ed. (Toronto, 1952), 112-21; and Emmanuel J. Sullivan, Christian W o l ' s Concept of the Possible (doctoral dissertation, The Catholic University of America; University Microfilms, 1971), esp. 169-7 1. Note that the Leibnizian conception of possible essences dynamically striving for existence is abandoned by Wolff. For a more general comment on Leibniz in this context: Philosophiaprimasive Ontologia, #760 (p. 567).
3 S D i s c ~ r s ~ s For Wolff's claim to originality:praeliminari~, ##77, 78 (p. 41). Cosmologia generalis (1731), "Praefatio" (p. 9*). Cf. Jean &ole, "Un essai d'ex- plication rationnelle du monde ou la Cosmologia generalis de Christian Wolff," Giornale di metajisica, 18 (1963), 622-50. Ernst Kohlmeyer argues strongly in his Kosmos und Kosmonomie bei Christian Wolf (Gottingen, 191 I), esp. 61-67, for the importance of Wolff's idea of the universe, calling it the nerve or central point of his entire philosophy.
38Jean h o l e , "Cosmologie wolffienne et dynamique leibnizienne. Essai sur le rap- ports de Wolff avec Leibniz," Les Ptudes philosophiques, 19 (1964), 5. This article is the basis for much of the interpretation given in the following paragraph of the text.
256 CHARLES A. CORR
relationship, and the last permits both efficient and final ~ausality.~' In addition to matter or extension, bodies are endowed with both inertial and active or motive forces. Finally the whole doctrine rests upon a theory of simple substances or "elements" which are the ultimate units of larger, compound beings.
Up to this point it is difficult to discern or affirm much difference between Wolff's cosmology and that of Leibniz. But if we examine more closely the theory of "elements," we find that Wolff explicitly re- jects an identification of his view with that of classical Greek atomism or with the Leibnizian doctrine of monads. As against the "material atoms" of ancient philosophy, which are said to be divisible in theory though not in practice, Wolff describes his elements as "atoms of nature" which are indivisible in t hemse lve~ .~~ hasMoreover, Jean ~ c o l e shown that Wolff's elements differ from Leibniz's monads in at least three important ways. Leibniz's monads are metaphysical points characterized by a vital activity, a kind of perception, whereby they may be likened to spirits or souls. Furthermore, Leibniz denies that one monad can physically influence another in any way; their only relation- ship is ideal through the good offices of God. By contrast, Wolff's ele- ments are indivisible physical points; the active force which they possess is also physical in character; and finally, Wolff carefully refuses to take a position as to whether the passions of his elements are real or only apparent, though he is aware of Leibniz's stand. In short, where Leibniz approximates to panpsychism and idealism, Wolff is more physical and realistic. The distinction between the two positions at this juncture is considerable; it cannot be dismissed as a "merely nominal differen~e."~~
e) Psychology. Wolff divides psychology into two complementary
a7Beck(Early German Philosophy, 269-70) suggests that "Wolff's theory of space and time is based upon Leibniz's, yet differs from it in a significant way." His argument is that, for Leibniz, both space and time "are not substances, not ontological primitives, but are dependent upon the real, though not dynamic, relations among substances." By contrast, Beck believes that Wolff holds, on the one hand, "a subjectivistic theory of space" which depends upon the dynamic relations between substances and, on the other hand, a realistic theory of time. An older survey which considers Wolff's views on these questions is Werner Gent, Die Philosophie des Raumes und der Zeit: Historische, kri- tische und analytische Untersuchungen (Bonn, 1926), 207- 16.
W f . Cosmologia generalis, ##181, 186 (pp. 145, 148). In the letter to Manteuffel (cited in footnote 8 above) Wolff says that Leibniz's system begins at a point where his own stops, and that he did not use the monads, the basis of Leibniz's system, in his own work because he regarded them as an unsolved riddle. The quote is reproduced in Wuttke (82-83) and Lenders (139).
a9The phrase is from John V. Burns, C.M., Dynamism in the Cosmology of Chris- tian Wolf l A Study in Pre-critical Rationalism (New York, 1966), 87. Cf. Cosmologia generalis, "Praefatio" (p. 14*), and ##182n & 243n (pp. 146 & 186).
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parts: an "empirical" and a "rational" psychology. The task of em- pirical psychology is to organize the facts of human psychological experience so as to establish the principles from which reasons can be drawn for that which occurs through the soul.40 This involves an ar- gument for the existence of the human soul, a review of its cognitive and appetitive operations, and an attempt to define the basic vocabulary of psychology. Wolff's argument for the existence of the soul is a revised version of the Cartesian cogito which leaves the status of the body ~nse t t led .~ 'Nevertheless, it provides a sufficient base for rational psychology to begin the task of providing a definition of the nature of the This definition is directly dependent upon the resources and requirements of Wolff's ontology. That is, various faculties explain the possibility of psychological activity, but they do not account for its actuality. Hence, there must be an additional principle "which contains in itself the sufficient reason of the actuality of the action.'743 This prin- ciple is an ever-present, dynamic tendency to action, a force which constitutes the very essence or nature of the human
Two things are prominent throughout Wolff's psychology: the continued absence of a direct monadological theory and a strong tendency to a classic dualism of mind and body. The latter is sharply
40Psychologia empirica (1732), #1 (p. 1). Cf. Jean ~ c o l e , "Des rapports de l'experience et de la raison dans l'analyse de 1'Lme ou la Psychologia empirica de Chris- tian Wolff," Giornale di metafisica, 21 (1966), 589-617, Anna Maria Vittadello, "Experience et raison dans la psychologie de Christian Wolff," Revue philosophique de Louvain, 71 (1973), 488-51 1, and my "Christian Wolff's Distinction Between Empirical and Rational Psychology," Studia Leibnitiana, Supplementa, Bd. XIV,11434.
41Cf.Psychologia empirica, #16 (p. 12): "Whatever being is actually conscious of it- self and of other things outside itself, that being exists. But we are actually conscious of ourselves and of other things outside ourselves. Therefore we exist." Note that this ar- gument differs from Descartes's in form and in its assertion that we experience a double plurality of conscious observers and of extra-mental objects. These points, together with some developed below in the text, are discussed in R. J . Blackwell, "Christian Wolff's Doctrine of the Soul," JHI, 22 (1961), 339-54.
4ZCf.Psychologia rationalis (1734), # l (p. 1): "Rational psychology is the science of those things which are possible through the human soul." Cf. Jean Ecole, "De la nature de l'Lme, de la dduct ion de ses facultCs, de ses rapports avec le corps, ou la Psychologia rationalis de Christian Wolff," Giornale di metafisica, 24 (1969), 499-531. Mariano Campo's "Una tesi psicologica dell'intellettualismo wolfiano: la deduzione dalla 'vis repraesentativa'," Rivista difilosofia neo-scolastica, 30 (1938), 492-5 18, cor- responds with minor alterations and the omission of a few pages, to a section in his book (op. cit., I, 346-89).
4aThis is Wolff's nominal definition of the term "force." Philosophia prima sive Ontologia, #722 (p. 542).
44Cf.Psychologia rationalis, #66 (p. 45): "The essence of the soul consists in the force of representing the universe limited materially by the placement of the organic body in the universe and formally by the constitution of the sensory organs."
258 CHARLES A. CORR
illustrated by the way in which the two parts of Wolff's psychology treat the problem of the "commerce" between soul and body.45 Em- pirical psychology discloses the fact that mental and bodily actions oc- cur simultaneously, but it is unable to explain how or why this is the case. Rational psychology seeks a systematic explanation of this inter- dependence, but Wolff admits that he has found no reason in the nature of the soul from which the necessity of its interaction with the body can be deductively demonstrated. As a result, he is forced to fall back on a hypothetical explanation. After rejecting as unsatisfactory the ac-counts suggested by the theories of physical influx and occasionalism, Wolff accepts the system of pre-established harmony as the most likely explanation. However, he is careful to note that pre-established harmony is not without its own difficulties. For that reason, it can be accepted only as a probable explanation limited to the relationship be- tween the human soul and body. It is not a fundamental metaphysical or even psychological principle for Wolff and it is not an essential link in the chain of demonstrated propositions in his metaphysics and practical p h i l o s ~ p h y . ~ ~
f ) Natural Theology. Like psychology, Wolff divides natural theology-"the science of those things which are possible through G~d"~~- in totwo major parts: Part I contains an a posteriori demon-stration of the existence and attributes of God drawn from the charac- teristics of the visible world; Part I1 treats the same subjects from an a priori standpoint based on the notion of a most perfect being and the nature of the human soul. The student of Wolff's metaphysics and of Kant's critique of natural theology will be especially interested in the two principal arguments which Wolff advances to prove the existence of God, but we can only sketch them here and draw attention to a few of
45Cf.Psychologia empirica, ##947-64 (pp. 71 1-20); Psychologia rationalis, ##530-642 (pp. 45 1-587).
46Wolff insists on the limited and distinctive character of his view of pre-established harmony at Psychologia rationalis, "Praefatio" (pp. 13*-16*), and #638n (pp. 580-81). His claim is developed by Gerd Fabian, Beitrag zur Geschichte des Leib-Seele- Problems: Lehre von der prastabilierten Harmonie und vom psychophysischen parallelismus in der Leibniz- Wolffschen Schule (Langensalza, 1925), esp. 32-47. Rainer Specht notes that the change from the Leibnizian hierarchy of monads to Wolff's dualism of heterogeneous substances affects their corresponding theories of pre-es- tablished harmony: Innovation und Folgelast: Beispiele aus der neueren Philosophie- und Wissenschaftsgeschichte (StuttgartIBad Cannstatt, 1972), 160-62.
47Theologia naluralis, I (1736), #1 (p. 1). (Page references for both volumes are to the Verona edition of 1779.) Older studies of Wolff's natural theology include Paul A. Heilemann, Die Gotteslehre des Christian Wol@ Versuch einer Darstellung und Beurteilung (Leipzig, 1907), and Harry Levy, Die Religionsphilosophie Christian Wolff's (Regensburg, 1928). More recently, see James Collins, God in Modern Philosophy (Chicago, 1959), 133-43, and Anton Bissinger, op. cit.
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their salient features. The aposteriori argument proceeds as follows48: the human soul exists or we exist; there must be a sufficient reason why this is; the reason must be contained in us or in some other being; in either event, the reason must lie in a necessary being if it is to be truly sufficient; hence, a necessary being exists; a necessary being is an ens a se or one which contains the sufficient reason of its existence in its own essence, i.e., an "ens a se exists therefore, because it is possible"49; neither the visible world, its elements, or the human soul can be ens a se; hence, God exists, where the term "God" is defined nominally as "the ens a se in which is contained the sufficient reason of the existence of this visible world and of our souls."50 Many aspects of this argument are typical of Wolff, such as the direct reliance upon the principle of sufficient reason, the vagueness or ambiguity of the existential affirmation in the minor premise,51 the transition from necessary being to ens a se to God, the character of the appeal to possibility, and the use of a nominal definition in the final stage of the argument. The apriori argumen t begins with a definition of ens perfectissimum as that being "to which belong all compossible realities in the absolutely highest degree.'752 Once we add to this another nominal definition of God as ens perfectissimum, we know that God is possible. Now, existence is a compossible reality and necessary existence is the highest degree of existence, the degree appropriate to an ens perfectissimum. Hence, God possesses necessary existence, i.e., He exists necessarily. In other words, "God exists through His essence or His existence is e~sen t i a l . "~~
48The heart of the argument is in Theologia naturalis, I, #24 (p. 13); cf. Jean &ole, "De la dtmonstration a posteriori de I'existence et des attributs de Dieu, ou la Theologia naturalis, Pars I de Christian Wolff," Giornale di metafisica, 28 (1973), 363- 88, 537-60, and my "The Existence of God, Natural Theology, and Christian Wolff," International Journalfor Philosophy ofReligion, 4 (1973), 105- 18.
49Theologia naturalis, I, #34 (p. 16). Wolff argues that the ability of the essential constituents of the ens a se to explain both its possibility and its actual existence is the special privilege of this unique being. Thus he concludes (in the note to the same para- graph) that "existence is not inferred from possibility in general, nor is existence de- termined by possibility considered in general o r in itself." This leads James Collins (op. cit., 139) to observe that the argument is a t least "covertly apriori."
50Theologia naturalis, I , #67 (p. 27). 51Wolff argues (ibid. #24n; p. 14) that this ambiguity is actually an advantage be-
cause it means that "demonstration of the present proposition is thus independent of all the hypotheses of the philosophers," i.e., the hypotheses of materialism, idealism, and the like.
52Zbid.,I1 (1737), #6 (p. 2). The argument itself appears at ibid., #21 (p. 8), and Wolff comments on it in the unpaged Preface to the volume: "Therefore, the existence of the deity is truly demonstrated from the notion of the most perfect being and the same is derived from the contemplation of our soul. And thus the demonstration proceeds no less a posteriori than if it were derived from the contemplation of this visible universe, just as we did in the first part." 531bid.,#27 (p. 9).
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After the existence of God has been established, Wolff turns im- mediately to a description of the divine nature. Perhaps the most notable aspect of this portion of the text is the absence of the familiar Scholastic discussion of whether and how man can know or speak of God.54 Though he occasionally refers to a metaphorical, eminent, or even analogical use of predicates, Wolff does not develop a consistent solution to this problem. Wolff obviously feels confident that he can somehow bridge this gulf between man and God, though his frequent reminders of the inscrutability of the divine nature are not mitigated by a comprehensive doctrine such as the familiar Thomistic theory of analogy. This is most evident in Wolff's description of the three prin- cipal attributes of God-intellect, power, and will-which combine to provide the sufficient reason for the actuality of the visible universe. In a way which will not be unfamiliar to students of Leibniz, Wolff main- tains that the divine intellect explains the intrinsic possibility of the world, the divine power accounts for its extrinsic possibility, and the divine will determines its actual existence.
When we look more closely at this account of creation and the divine attributes, however, we find that it has some interesting and dis- tinctive features. First, Wolff explicitly rejects the radical voluntarism of Descartes by directly linking the intrinsic possibility of created things to the divine intellect. God simply cannot create anything which is in- herently self- contradictor^.^^ Further, God can only create that which is compossible or compatible with the nexus of other things that constitute a particular universe. These are the limits within which God's will exercises the divine freedom. At the same time, Wolff is careful to argue that God's will cannot be regarded as a mere appendage to divine omniscience and omnipotence. Since the divine will is inscrutable to man, Wolff7s philosophy can admit no strict demonstration of a deduc- tive reason for the existence of the world. Necessity in the created uni- verse is no more than hypothetical because the existence of any world at all is a contingent fact and because the divine creative act is not coerced by the objective, existential dynamism of a world of possible essences.
"Thus Bissinger (op.cit., 207) says: "The question of the possibility of knowledge of God is not explicitly posed by Wolff. That God can be known by man in His existence, His essence, and His attributes is just as self-evident for him as for Descartes, Clauberg, and Leibniz." This relates to the larger problem, mentioned earlier, of the lack of a developed epistemology in Wolff. "With astonishment one learns that no book is found, either among German or the Latin works of Wolff, that is exclusively con- cerned with epistemology" (ibid., 55).
55Cf. ibid., I,#313 (p. 151). In the following paragraph the point is put positively: "Whatever God wills is possible."
CHRISTIAN WOLFF AND LEIBNIZ 26 1
It may appear that Wolff abandons this position by seeking for a fitting reason-a ratio quaedam con~enientiae~~-for God's decision to create the particular world in which we find ourselves. And Wolff does follow Leibniz in claiming that the visible universe is the best of all possible worlds. However, the reason for the actualization of this world depends on the principle that "God wills whatever He represents to Himself as the best, both in itself and in relation to Him~elf."~' This re- quirement calls for the interaction of both objective and subjective fac- tors in God's decision. Thus, Wolff admits that God may bring other possible worlds-one or all of them-into actual existence along with the best one. God's will, in short, remains free for Wolff in a way which is not conceivable according to Leibniz's principle^.^^
4. A Provisional Conclusion-No attempt has been made in this article to offer a definitive account of the relationship between Christian Wolff and Leibniz. I have not attempted to hide my belief concerning the importance which attaches to the broad Cartesian influence on Wolff. In addition, I suspect that the significance of what is rather loosely termed the "school philosophy," though more difficult to trace and identify,59 is at least of equal weight. And, of course, I should not wish to deny that Wolff drew upon Leibniz in many important ways. My primary purpose has not been to develop these points here, but to throw into question the well-worn stereotype according to which Wolff can and must be viewed merely as a systematizer and vulgarizer of
56This phrase occurs, ibid., I, #460 (p. 196), in the course of an explanation of the thesis that "without any internal constraint God has willed some world to exist." I am indebted to James Collins (op. cit., 141-42) for the development of the points which follow in the present paragraph of our text.
57Theologia naturalis, I, #390 (p. 175). On God's ability to actualize other possible worlds-indeed, all of the possibles-see ibid., ##342-43 (p. 161). This doctrine may help to explain the fact that the well-known Leibnizian distinction between the ante- cedent and consequent will of God appears to be absent in Wolff.
58These observations suggest that Johann Erdmann and Karl Vorlander have wrongly assessed Wolf's natural theology. Erdmann says ( A History of Philosophy, Vol. II: Modern Philosophy, 3 vols., trans. W. S. Hough [London & New York, 1890; originally 18661, 228) that "in the last part of his Metaphysics, the Natural Theology . . . Wolff appears as merely a commentator, and often a slavish commentator, on what Leibniz had said in the Theodicy." Vorlander claims that "in natural theology Wolff seems completely dependent on Leibniz and his Theodicy"; Geschichte der Philosophie, Bd. II: Die Philosophie der Neuzeit bis Kant, 7th ed. (Leipzig, 1927), 234. Bissinger (op. cit.. 24) puts it more accurately: "Actually Wolff has taken many ideas from the Theodicy which really are Leibniz's . . . but to infer from this a complete dependence is not in accord with the facts. Rather, the theology has its principle source in the Scholastic tradition. Wolff's theology rests on a synthesis of this tradition, Leibniz's own ideas, and the mathematical method."
"Francis Ruello has illustrated some of these difficulties in his "Christian Wolff et la scolastique," Traditio, 19(1963), 41 1-25.
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Leibniz. I do not pretend to have said the final word on this subject, but I should like to call for the kind of thorough study which can substan- tiate or vitiate my view. In order to facilitate such study, I have made a conscious effort in the footnotes to identify many of the resources which are now available to us for this purpose in the form of the new edition (in progress) of Wolff's works and the relevant secondary literature, both new and old, which pertains to these issues.
Southern Illinois University at Edwardsville.