Leibniz: Logico-Philosophical Puzzles in the Law Law and Philosophy Library

VOLUME 105

Series Editors:

FRANCISCO J. LAPORTA, Department of Law, Autonomous University of Madrid, Spain FREDERICK SCHAUER, School of Law, University of Virginia, U.S.A. TORBEN SPAAK, Uppsala University, Sweden

Former Series Editors:

AULIS AARNIO, MICHAEL D. BAYLES{, CONRAD D. JOHNSON{, ALAN MABE, ALEKSANDER PECZENIK{

Editorial Advisory Board:

AULIS AARNIO, Secretary General of the Tampere Club, Finland HUMBERTO A´ VILA, Federal University of South Brazil, Brazil ZENON BANKOWSKI, Centre for Law and Society, University of Edinburgh, United Kingdom PAOLO COMANDUCCI, University of Genoa, Italy HUGH CORDER, University of Cape Town, South Africa DAVID DYZENHAUS, University of Toronto, Canada ERNESTO GARZO´ N VALDE´ S, Institut fu¨r Politikwissenschaft, Johannes Gutenberg Universitat, Mainz, Germany RICCARDO GUASTINI, University of Genoa, Italy JOHN KLEINIG, Department of Law, Police Science and Criminal Justice Administration, John Jay College of Criminal Justice, City University of New York, U.S.A. PATRICIA MINDUS, Uppsala University, Sweden YASUTOMO MORIGIWA, Nagoya University, Japan GIOVANNI BATTISTA RATTI, Department of Legal Sciences, University of Genova, Italy and Member of the Chair of Legal Culture at the University of Girona, Spain WOJCIECH SADURSKI, University of Sydney, Faculty of Law, Sydney, Australia HORACIO SPECTOR, Universidad Torcuato Di Tella, Argentina ROBERT S. SUMMERS, School of Law, Cornell University, U.S.A. MICHEL TROPER, Universite´ de Paris Quest - Nanterre, Institut Universtaire de France France CARL WELLMAN, Department of Philosophy, Washington University, U.S.A.

For further volumes: http://www.springer.com/series/6210 Alberto Artosi • Bernardo Pieri • Giovanni Sartor Editors

Leibniz: Logico- Philosophical Puzzles in the Law

Philosophical Questions and Perplexing Cases in the Law Editors Alberto Artosi Bernardo Pieri Department of Legal Studies - CIRSFID Department of Legal Studies - CIRSFID University of Bologna University of Bologna Bologna, Italy Bologna, Italy

Giovanni Sartor Department of Legal Studies - CIRSFID University of Bologna Bologna, Italy European University Institute Florence, Italy

ISSN 1572-4395 ISBN 978-94-007-5191-0 ISBN 978-94-007-5192-7 (eBook) DOI 10.1007/978-94-007-5192-7 Springer Dordrecht Heidelberg New York London

Library of Congress Control Number: 2013938265

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Springer is part of Springer Science+Business Media (www.springer.com) Je ne sc¸aurois laisser passer cette occasion sans vous entretenir, Monsieur, de quelques meditations que j’ay eues depuis que je n’ay pas eu l’honneur de vous voir. Entre autres j’ay fait quantite´ des reflexions de jurisprudence, et il me semble qu’on y pourroit establir quelque chose de solide et d’utile, tant pour avoir un droit certain (ce qui nous manque fort an Allemagne et peutestre encor en France) que pour e´tablir une forme de proce´s courte et bonne. Leibniz to Arnauld, 14 July 1686 (G II 60). Sed juris incertitudini mederi difficilius est. [But to remedy the uncertainty of the law is harder] Leibniz to Kestner, 5 September 1708 (D IV, 3, 254).

Contents

Abbreviations ...... xi

Introduction ...... xiii

1 Specimen of Philosophical Questions Collected from the Law ..... 1 Annex 1.A Texts from the Digest cited in the Specimen: A Selection ...... 47 Annex 1.B The Original Latin Text of the Specimen ...... 49 2 Inaugural Dissertation on Perplexing Cases in the Law ...... 71 Annex 2.A Texts from the Digest cited in the Dissertation: A Selection ...... 124 Annex 2.B The Original Latin Text of the Dissertation ...... 132

Bio-bibliographical Note ...... 151

References ...... 195

An Essay by S. Brewer: Law, Logic, and Leibniz. A Contemporary Perspective ...... 199

vii

Foreword

Why translate two of Leibniz’s first academic writings, the works of a young university student? The most obvious answer is: because this young student was Gottfried Wilhelm Leibniz. But there are also other, less obvious reasons. The most important of these reasons is the genuine intellectual interest these writings elicit, and in particular the freshness and originality of Leibniz’s reflections on what we have called “legal puzzles.” These fall under a range of legal issues to which Leibniz in these two short works applies his logical skills (still developing but already considerable, given his amazing precocity). There are puzzles resulting from cases of apparent conflict between law and philosophy (the latter broadly understood to comprise not only metaphysics but also mathematics, the empirical sciences, and theology). These puzzles sometimes arise from the fact that the same terms are used in different ways in philosophy and in law. Other times the puzzles arise from the fact that a certain principle is assumed to have universal application, while its use is only justified under particular pragmatic conditions, or from the fact that lawyers and jurists work within a defective conceptual framework. Some puzzles result not from an apparent conflict between law and philosophy but from the need to provide a deeper logical analysis of a conceptual issue. And finally there are cases which provide proper legal puzzles, i.e., those cases whose solution is doubtful because of the convoluted logical form of dispositions (expressions of intent) or because of a conflicting priority relationship. In addressing all these different kinds of puzzles, Leibniz always dissects the problem with the greatest clarity, disentangling its different aspects, and then proposes solutions, always reasonable and sometimes surprising. And he does not refrain from peppering his intellectual acrobatics with some humorous comments. We will not comment here on the specific issues addressed in the two works, since we have included extensive comments introducing each section of our translations. These comments we have provided to make Leibniz’s reasoning more accessible to the contemporary reader, who might have some difficulty extracting our young lawyer-philosopher’s subtle analyses from his writings, cast in the style of the legal and philosophical commentaries of the time. But we believe that these puzzles should be considered not merely as an object of philologico-historical

ix x Foreword interest, but also and especially as living examples of legal-philosophical reasoning, whose understanding requires an active engagement, rewarded by the intellectual enjoyment of following the processes of Leibniz’s brilliant mind. Another reason for translating these two youthful writings is that they usually receive little attention in works concerned with the development of Leibniz’s thought (see, for instance, Mercer 2001: 24, 45–6, and Antognazza 2009: 61–2, 65–6), and therefore these writings remain largely unknown. On the other hand, these early writings by Leibniz (among the few works by him published during his lifetime) have recently attracted increasing scholarly interest. From 1998 to 2009 there appeared the first modern-language translations of Leibniz’s Doctrina conditionum (Leibniz 1998), Disputatio juridica de conditionibus (Leibniz 2002), Nova methodus discendae docendaeque jurisprudentiae (Leibniz 2003, 2012), and Disputatio de casibus perplexis in jure (Leibniz 2009). In the same period, Leibniz’s youthful legal dissertations increasingly came under the focus of many Leibnizian scholars (among whom Armgardt 2001, Roinila 2007, Dascal 2008, Boucher 2008, Thiercelin 2008, Vargas 2008, Johns 2009, and Thiercelin 2011). But there still does not emerge from this body of work a comprehensive picture of those dissertations and of their role in Leibniz’s intellectual development. We hope the present translations will contribute to completing such a picture. The volume has been jointly edited by its three authors, who have translated the two Leibnizian works. Alberto Artosi and Giovanni Sartor have written the Introduction (apart from Sect. 2), as well as the comments introducing the single sections of Leibniz’s two works. Bernardo Pieri has written Sect. 2 of the Introduction, the Bio-Biographical Note and the footnotes and endnotes, and has also prepared all Annexes. A special thanks is owed to Filippo Valente for copy-editing the entire volume. Moreover, we are happy to include Stuart Brewer’s essay, “Law, Logic and Leibniz: A Contemporary Perspective,” which provides a much needed link to the current jurisprudential discussion. Abbreviations

A G. W. Leibniz, Sa¨mtliche Schriften und Briefe, ed. German (formerly Prussian) Academy of Sciences at Berlin. Darmstadt: Reichl, 1923- (reprint Hildesheim: Olms, 1972-). Cited by series, volume, and page, e.g., A VI/1 347. AG G. W. Leibniz, Philosophical Essays, ed. and trans. R. Ariew and D. Garber. Indianapolis: Hackett, 1989. D Gothofredi Guillelmi Leibnitii Opera Omnia. Nunc primum collecta, in Classes distributa, praefationbus et indicibus exornata, ed. L. Dutens, 6 vols. Genevae: Apud Fratres de Tournes, 1768 (reprint Hildesheim: Olms, 1989). Cited by volume, part, and page, e.g., D IV, 3, 253. FC G. W. Leibniz, Nouvelles lettres et opuscules ine´dits, ed. A. Foucher De Careil. Paris: Durand, 1857 (reprint Hildesheim: Olms, 1971). G Die philosophischen Schriften von Gottfried Wilhelm Leibniz, ed. C. I Gerhardt, 7 vols. Berlin: Weidmann, 1875–90 (reprint Hildesheim: Olms, 1965). Cited by volume and page, e.g., G II 60. GR G. W. Leibniz, Textes ine´dits d’apre´s le manuscrits de la Bibliothe`que Provinciale de Hanovre, ed. G. Grua. Paris: Presses Universitaires de France, 1948 (reprint New York: Garland, 1985). L G. W. Leibniz, Philosophical Papers and Letters, ed. and trans. L. E. Loemker, 2nd ed. Dordrecht: Reidel, 1976. R G. W. Leibniz, Political Writings, ed. and trans. P. Riley, 2nd ed. Cambridge: Cambridge University Press, 1988.

xi

Introduction

Biographical Background

Gottfried Wilhelm Leibniz was born in Leipzig on July 1, 1646, into an orthodox Lutheran family steeped in academic and legal tradition. His father was a professor of moral philosophy at the local university, where he also served as registrar.1 His mother was the daughter of a renowned lawyer,2 and after her parents died, she came under the guardianship of the distinguished law professor Quirinius Schacher. His maternal aunt was married to the eminent jurist Johann Strauch, who would exercise a considerable influence in shaping Leibniz’s legal vocation.3 In 1661, Leibniz enrolled in the University of Leipzig, where in 1662 he received a bachelor’s degree in philosophy, for which he wrote his first academic dissertation. This work was submitted in the canonical form of a disputation4 held in June 1663 under the chairmanship of Leibniz’s first teacher, Jakob Thomasius,5 and was

1 This university post may be to account for the frequent misconception that Leibniz’s father was (or was also) a lawyer. 2 Wilhelm Schmuck, whose legal library was incorporated into the library of Leibniz’s father. 3 Johann Strauch is mentioned in Question VII of the Specimen as “the most noble Dr. Strauch, now Proto-Syndic at Brunswick, my relative and very honoured patron”. In Leibniz’s early legal writings, Strauch is also mentioned in the Disputatio juridica de conditionibus (see note 8 below) and in the Nova methodus discendae docendaeque jurisprudentiae (A VI/1 347). 4 The disputatio was the standard method of examination for access to the various academic degrees. It consisted in a public discussion of a number of theses, with one disputant arguing pro and the other arguing contra (a closely related issue is addressed in Question II of the Specimen)—all this under oversight of a chairman whose role was to ensure compliance with the rules of disputation. 5 Jakob Thomasius (1622–1684), the father of Christian Thomasius, was professor of rhetoric, dialectic, and moral philosophy. He is mentioned in Question VIII of the Specimen as “our Illustrious Thomasius, my preceptor and highest mentor,” and again in Question XII as “our Thomasius ὁ θαυμάσιoς” (a witty pun on the word Thomasius, spelled thaumasios, meaning “wonderful,” so as to give “wonderful Thomasius”). Thomasius is also mentioned in On Perplexing Cases,IV,aproposof “a course he taught in 1662 in Leipzig on Machiavellism.” On Thomasius and his importance to Leibniz’s intellectual development, see Mercer (1999: 28–32).

xiii xiv Introduction later published under the title Disputatio metaphysica de principio individui (Metaphysical disputation on the principle of individuation).6 The Disputatio metaphysica inaugurates the series of Leibniz’s early publications, to which the works here translated belong. The following passage illustrates the way education was set up at German universities when Leibniz was studying in Leipzig: Like most of his learned countrymen, Leibniz’s first published works were versions of the academic disputations required to mark the various major stages of his higher education. Although many of the students who matriculated in seventeenth-century universities chose to sidestep formal degree studies for one reason or another, the ordinary formal course of study began with a Bachelor’s degree in the general “arts” or “philosophy” course and then followed this with higher degrees in philosophy or – far more normally – with Bachelor’s, Master’s and Doctoral degrees in one of the three “higher faculties” of theology, law, or medicine (Antognazza 2009: 57). In October 1663, Leibniz went back to Leipzig after a summer term at the University of Jena (where he met Erhard Weigel).7 Faced with the dilemma whether to complete his studies in philosophy or move on to one of the higher faculties, he decided to do both, simultaneously enrolling in the law faculty of his native Leipzig, where he began his legal apprenticeship under professors Quirinius Schacher and Bartholomaeus Schwendendo¨rffer. As Leibniz himself would later recall in his biographical sketch: “I felt that my prior study of history and philo- sophy made jurisprudence very easy to acquire, so that I had no difficulty in understanding the laws, and since I needed not linger over theory, which I despised for its easiness, I turned my attention to the practice of law” (FC 383). He adds that he was intrigued by the role of the judge, but that he despised the lawyers’ chicanery, and that for this reason he had never wished to plead in court. In 1664, Leibniz earned his Master of Philosophy, and that same year he defended and published his dissertation, Specimen quaestionum philosophicarum ex jure collectarum (“Specimen of Philosophical Questions Collected from the Law”), in which he brought his recent legal training to bear on his philosophical interests. In the meantime he visited his uncle Johann Strauch in Brunswick. The illustrious scholar was struck by the young man’s rare talent and warmly

6 A VI/1 3–19. The work addressed the classic Scholastic issue of the nature of individual substance. 7 Erhard Weigel (1625–1699) was professor of mathematics and astronomy. He is mentioned in Question XVI of the Specimen as “the Illustrious Weigel, professor of Mathematics in Jena, my preceptor and revered patron”, as well as in On Perplexing Cases, II, where Leibniz mentions Weigel’s main work, Analysis Aristotelica ex Euclide restituta (1658): see note 54 below (on Weigel, see also notes 32 and 52 below). For an account of Weigel and his influence on Leibniz, see Mercer (1999: 33–35). Interestingly, in Question VII of the Specimen Leibniz mentions another professor at Jena, one “Dr. Posner, professor of Physiology in Jena,” along with his work Dissertatio de principatu partium. This Posner is Caspar Posner, Sr. The work cited is almost certainly Posner’s Disputatio physica de principatu partium in corpore animalium, published in Jena in 1663. According to Busche (1997: 104), Leibniz’s reference to Posner may be evidence that during his summer semester in Jena he attended Posner’s medical seminar. Introduction xv encouraged him to pursue the study of law.8 In September 1665, Leibniz earned his bachelor’s degree in law, for which he wrote the dissertation Disputatio juridica de conditionibus (Juridical disputation on conditions) under the supervision of Schwendendo¨rffer.9 A few months later, on March 17, 1666, he earned his habili- tation in philosophy with the first part of what was to become the Dissertatio de arte combinatoria (Dissertation on combinatorial art),10 published in the same year. Immediately thereafter, he turned to the study of law, working on his dissertation for the degree of Doctor of Law. Astonishingly, the law faculty refused him the title for reasons that are unclear: perhaps the scheming of some older students or the dean’s wife’s ill will toward Leibniz.11 As a result, in October 1666, Leibniz transferred to the law faculty of the University of Altdorf (near Nuremberg), where in short order he completed and submitted his doctoral dissertation, Disputatio inauguralis de casibus perplexis in jure (“Inaugural Dissertation on Perplexing Cases in the Law”). In February 1667, at the age of 21, Leibniz obtained his doctor’s degree and, having declined an offer for an academic position,12 he set off for Frankfurt. On his way there, “from a guesthouse to the other, without books,” he wrote his first (and only) jurisprudential treatise, Nova methodus discendae docendaeque jurisprudentiae (A new method for learning and teaching jurisprudence),13 through which he planned to gain favour with the prince elector of Mainz. Indeed, this new work made such a good impression on the prince elector that he enlisted the young scholar in his service by appointing him assistant to his Hofrat (court counsellor), Hermann Andreas Lasser, who was working to reform the electorate’s legal code. In 1669, at the age of 23, Leibniz was appointed assessor (i.e., judge) to the High Court of Appeals,14 notwithstanding his Protestant persua- sion (the court of Mainz was Roman Catholic). This was the first of a series of increasingly prestigious offices he would hold as a jurist.15 In the same year, he collected his first three legal dissertations into a single volume under the title

8 See Strauch’s letter to Leibniz of 6 July, 1665 (A VI/1 124). Leibniz acknowledges his debt to Strauch in the preface to the Disputatio juridica de conditionibus (A VI/1 101). 9 The disputation was held in two sessions, in July and August 1665, and published in the same year under two separate titles: Disputatio juridica de conditionibus (A VI/1 97–124) and Disputatio juridica posterior de conditionibus (A VI/1 125–50). 10 A VI/1 163–230. 11 Aiton (1985: 65). 12 This is Leibniz’s first manifestation of that “preference for a career in the world rather than in the academy” (Mulvaney 1994: 413), a preference that would keep him away from the universities throughout his life. 13 A VI/1 259–364. The reference to the extemporaneous writing of this work (“inter diversoria, sine libris”) is on p. 292. See also Leibniz’s letter to Placcius of 10 May, 1676 (A II/1 260). 14 This was the electorate’s highest tribunal. 15 Hofrat in Hanover in 1677, Geheimer Justizrat (privy counsellor of justice) in Hanover in 1696 and in Brandemburg in 1700, privy counsellor of justice to the Russian tsar Peter the Great of Russia in 1712, and Reichshofrat (member of the Imperial Aulic Council, one of the empire’s two higher appeals courts) in 1713. xvi Introduction

Specimina juris (Specimens of the law). This ends our story.16 In the following sections we offer an overview of Leibniz’s early legal thinking. But first, in order to provide the proper setting, we will paint, at least in outline, a picture of the state of the law in early modern Europe.

Law in Leibniz’s Time17

When Leibniz made his debut as a jurist, the legal landscape in Western Europe was marked by divergent, albeit concurrent, trends. On the one hand was the advent of new sources of law, especially the legislation enacted by national monarchies, coupled with the disruption of the medieval ideal of the unity of the respublica christianorum (republic of Christians) brought about by the Papal Schism – two forces that had been conspiring to undermine the ius commune, leading to its progressive confinement to the role of a mere complement to the different iura municipalia (i.e., the municipal laws of states and cities). In Germany, in particular, no sooner did the ius commune reach its heyday – with its reception through the institution of the Imperial Chamber Court (the (Reichskammergericht)18 – than its influence began to wane. Even so, partly on account of the empire’s inherent weakness, and partly on account of its fragmentation into a plurality of states subject to powerful municipal particularisms (every city had its own senate, council or parliament, and courts), the judges became increasingly powerful, so much so that they lost sight of the keen medieval awareness of the judge’s subordination to the law.19 On the other hand, those concerned to secure the certainty of the law often pinned their hopes on the absolutist pretensions of the sovereigns, who at that time, especially after the Peace of Westphalia (signed just 2 years after Leibniz’s birth), were keen to appropriate the law by reducing it to their own authoritative statements. This process had started in the late fifteenth century and can be regarded as epitomized by the fate of the closing remark in Bartolo da Sassoferrato’s Tractatus de regimine civitatis: “So we see that some things concerning the tyrant

16 Leibniz’s Mainz period ended with his departure for Paris on 19 March, 1672. He would never return to Mainz. 17 This section is by Bernardo Pieri. 18 The Imperial Chamber Court was among the first central courts of the empire. It was established in 1495 by Emperor Maximilian I (1486–1519) at the request of the Diet of Worms, which sought to restrain the emperor’s personal influence in legal (and especially feudal) matters. Indeed, half of its members were lawyers trained in Roman law, so as to offset the number of those who were members by hereditary privilege, and through this composition the court was instrumental in the final adoption of Roman law as the common law of the Empire, in the form of both the Justinian Corpus iuris and the exegetical and doctrinal works of the medieval jurists. 19 The power of the supreme state courts was such that the judgments they delivered were mostly based on what came to be known as the principle of “equitable arbitrariness” (secundum conscientiam). Introduction xvii pertain to the jurists” (ideo de tyranno aliqua ad juristas spectancia videamus).20 This remark, appearing in Bartolus’ fourteenth-century manuscripts, disappeared from the printed editions, reflecting the modern princes’ unwillingness to submit to the jurist’s judgment and to grant jurists an area of exclusive competence (Bellomo 1994: 215). Roman law had been under attack for over two centuries. First came the sixteenth-century rationalists, who called into question the classic Roman partition of law into the three domains of personae, res, and actiones (respectively dealing with individuals and their family relationships; with things, property, and contracts; and with the means by which to claim and protect rights),21 and who in the footsteps of the Scuola Culta,22 and drawing on the humanistic canons (reevaluated most notably in light of Melanchthon’s work), objected to the arrangement of the Pandects on the ground that it was in such disarray as to make them ineffective. It was Johann Apel (1486–1536)23 who led the way, by inspiring new attempts to systematize the Pandects, especially on the part of Sebastian Derrer ({ 1541),24 Melchior Kling (1504–1571),25 and Conrad Lagus (1500–1546).26 Lagus was among the first to reclaim the philosophical dimension of the law,27 a dimension he viewed as linked to its positive one (which he termed “historical”), in that “the form of the institutes of positive law derived from the natural source viewed as a necessary foundation” (Birocchi 2002: 15). To this end Lagus invoked the old distinction between a ius naturale primaevum (the law common to all animals) and a ius naturale secondarium (the Romans’ ius gentium, which like other jurists he called ius divinum)28 and claimed that the latter included not only what had been laid down in the Scriptures but also what “springs from the judgment of reason” (ex iudicio rationi nasci).29 In this way, the law’s systematic order came to be viewed as the realization of God’s design through human reason.

20 The critical edition of Bartolus’s treatise is found in Quaglioni (1983). 21 This partition would also be criticized by Leibniz in the Nova methodus on the ground that it is a factual, not a legal, partition (A VI/1 295–9). 22 The term Scuola Culta designates the humanistic strand of legal science, which paved the way for the application of philology and of historical critique to the study of law. 23 Author of Methodica dialectices ratio ad jurisprudentiam adcommodata (Norimbergae, 1535) and of Isagoge per dialogum in quatuor libros Institutionum (Wratislaviae, 1540). 24 Author of Iurisprudentiae liber primus, instar disciplinae institutus et axiomatibus magna ex parte conscriptus (Lugduni, 1540). 25 Author of Enarrationes in libros IV Institutionum (Francoforti, 1542). 26 Author of Iuris utriusque traditio methodica (Francoforti, 1543). This work was published without the author’s permission. He replied the following year with a Protestatio. On this whole affair, see Theuerkauf (1968: 200 ff.). 27 He did so with Johann Oldendorp, author of Iuris naturalis, gentium, et civilis eisagoge (Cologne, 1539). 28 This distinction is also espoused by the young Leibniz in Question VIII of the Specimen. 29 Lagus (1543: 11), quoted from the Lyon edition of 1566. xviii Introduction

Along a similar path, the natural lawyers of the seventeenth century worked out an objective and rational conception of natural law entailing a sharp distinction between law and theology.30 Indeed, there are still in Grotius deep influences of the theologians of the School of Salamanca,31 as well as traces of the method of the Scuola Culta (Birocchi 2002: 169). But with Thomas Hobbes (1588–1679), Spinoza (1632–1677), and especially Samuel Pufendorf (1632–1694) and his most promi- nent follower, Christian Thomasius (1655–1728), the need for a separation between law and theology became a cornerstone of the natural law doctrine, along with the belief that the law’s basic principles should be approached scientifically through the application of mathematical methods.32 To “define” and to “systematize” became widely accepted scientific imperatives, and the certainty of the law was increasingly understood as something that could be attained more geometrico.33 The systematic construction of natural law as the science-based “law of reason” was supposed to replace Roman law,34 but jurists still received a predominantly Romanist training, and Roman law, especially in Germany, was firmly rooted as the common law of the land in judicial practice.35 Although by that time this common law could no longer be identified with the Justinian Corpus iuris (still less with

30 The seventeenth-century revival of natural law is part of a more pervasive cultural process begun at the outset of the sixteenth century with the publication of Jacopo Sannazzaro’s interna- tionally renowned poem L’Arcadia (1502). Drawing inspiration from Virgil’s Bucolica (in turn inspired by Theocritus), Sannazzaro depicted the idyllic world of shepherds and nymphs as a moral allegory meant to conjure up an imaginary Golden Age. The fondness for this fanciful world is evidenced by the wide success attained by literary works like Torquato Tasso’s Aminta (1573), Giovan Battista Guarini’s Pastor fido (1590), and Giovan Battista Marino’s poems (which were translated into English, German, and even Dutch), as well as by emblematic paintings like Nicolas Poussin’s The Shepherds of Arcadia, not to mention an endless series of musical works. 31 The theological school of the University of Salamanca was founded by Francisco de Vitoria (1492–1546) and included among its leading figures the theologian-philosopher-jurists Domingo de Soto (1494–1560) and Francisco Suarez (1548–1617). The school sought to reconcile Aquinas’s thinking with the humanistic view of man and his relation to God. 32 An example was the view of both Pufendorf and Weigel that moral entities (entia moralia) were subject to mathematically determinable laws, precisely in the manner of physical entities. On Weigel, see note 52 below. Pufendorf’s “geometric” approach to jurisprudence (in his Elements of Universal Jurisprudence) is mentioned by Leibniz (together with Hobbes’s Elements of Law and of Citizen) in the Nova methodus, II, 6 (A VI/1 295). 33 Although Leibniz would himself embrace this view, he was always consistently hostile to the idea of a separation between law and theology because of his belief, first stated in the Dissertatio de arte combinatoria (A VI 190) and then in the Nova methodus (A VI/1 294), that theology is part of a universal jurisprudence embracing laws both human and divine. 34 In the fragmented Germany, it was especially Hermann Conring (1606–1681) who made the case against Roman law, with his influential De origine iuris Germanici (Helmstedt 1643), eulogizing a purportedly native German law founded on time-honoured customs uncorrupted by Roman law. Conring, an eclectic scholar of Aristotelian lineage, established contacts with Leibniz after receiving a copy of the Nova methodus, and he also corresponded with Leibniz in the 1670s. 35 See note 18 above. Introduction xix canon law, which had entirely lost its vitality),36 the latter survived as the ratio scripta of the law,37 providing the underlying legal unity the new centralizing states were still unable to establish. Even so, throughout Leibniz’s long legal career, Roman law remained the object of conflicting stances. Whereas Georg Adam Struve (1619–1692), in his 1670 Jurisprudentia romano-germanica forensi, endeavoured to fit the principles and institutes of German law into the dogmatic and institutional scheme of Justinian law, Pufendorf and Christian Thomasius carried on Conring’s effort to lessen the influence of Roman law on German judicial practice.38 Toward the end of his life, Leibniz took up a correspondence with Heinrich Ernst Kestner (1671–1723),39 who in De statu jurisprudentiae, necessari- aque juris naturalis et civilis conjunctione (1699) had invoked Leibniz in support of his criticism of Roman law and his preference for natural law and traditional German law (G 682). Leibniz replied that, although the Roman laws have much that is “obscure, perplexing and redundant,” they must be considered the basis of the law: going back to ancient German laws, with their innumerable traces of barbarism, would be tantamount to feeding on acorns after having harvested corn (inventa fruge glandibus vesci). On the other hand, the body of the Roman laws could be reduced to a few general rules “in which both equity and meaning would appear in a clear light” and “all the variety of cases” would be “encompassed as if it were encircled with toils.”40 That is what Leibniz had dreamed of from the time he “first set [his] feet in the paths of jurisprudence,”41 and what he kept on dreaming of for the rest of his life. In his last letter to Kestner, written just a few months before dying, Leibniz reaffirmed all the basic tenets of his lifelong meditation on law:42 his admiration for the Roman jurists and the quasi-geometrical subtlety of their reasoning, an admiration first expressed in the preface to De conditionibus (A VI/1 101); his assimilation of Roman law to natural law, a view expounded as

36 In the sixteenth century, canon law had “lost its primacy as a normative science”, and owing to its increasing positivization, it “was turning more and more into an ecclesiastical discipline” (Prodi 2000: 190). 37 This is probably what Leibniz was referring to in his letter to Kestner of 1 July, 1716, where he commented that “in the meantime [...] the best course is to consider the corpus of the old laws as having for us the force not of law but of reason (vim non legis, sed rationis) and, as the Gauls say, of great Doctor” (D IV, 3, 269). On Leibniz’s exchange with Kestner, see note 39 below and the text corresponding to the note. 38 According to Thomasius, the German peoples could dispense with Roman law because natural law and the law of nations, being the “dictate of right reason” (dictamen rectae rationis), were independent of Roman law (a position emphatically rejected by Leibniz), and the basic principles of law became established among these peoples before they even had any notion of Justinian law. 39 D IV, 3, 253–69 (additions in G 681–99). This exchange lasted from 1708 to 1716, the year of Leibniz’s death. 40 Leibniz to Kestner, 5 September, 1708 (D IV, 3, 253–54). See Kestner’s reply of 12 September, 1708 (G 682–85). 41 Leibniz to Hobbes, 13/23 July, 1670. See full quotation at note 58 below. 42 Leibniz to Kestner, 1 July, 1716 (D IV, 3, 267–69). It is odd that in summarizing this letter, Dascal (2008: 73, note r) misdescribes it having been written by Kestner to Leibniz. xx Introduction early as in the Nova methodus;43 and the need for a “concise, clear, sufficient new Code” that would bring order and certainty to the confusing multitude of laws, a code he had been concerned with enacting as a legal reformer,44 ever since the days of the Nova methodus and his collaboration with Lasser.45 It is now time to follow Leibniz in his first forays into jurisprudence.

The Quest for Certainty: Leibniz contra Judicial Discretion

When Leibniz wrote the Specimen, no particular connection was seen to exist between law and philosophy, still less between law and such domains of knowledge as physics and mathematics. Hence, the Specimen can rightly be regarded as the first evidence of Leibniz’s impressive intellectual independence and originality. The young scholar’s bold contention was that law needs philosophical under- pinnings. For, as he writes in the Preface, “many places in [the] law would be an inextricable labyrinth without the guidance of philosophy.” Having argued this point, he reexamines a variety of questions drawn from Roman law in a progression from logic to metaphysics going through mathematics, physics, physiology, and zoology.46 This might not seem enough to conjure into being even the barest outline of a legal conception. But a careful reading of the text reveals the direction the young scholar was already taking. Leibniz’s most important remark appears in Question II, where he discusses the vexed issue of the allocation of the burden of proof: Thus it is necessary to extract the truth from the deeds and from what has been proved in whatever licit way, so that the matter can be decided. From which it follows that the burden of proof should be imposed upon the party that can discharge it most easily, in order that the matter should not remain without a decision. Two years later, we find Leibniz holding, with Plato, that in any state whatsoever a judicial matter is the better treated, the less is left to the discretion of the judge (in arbitrio judicis).47

43 See Sect. 5 below. 44 Equally important for him, in advocating for enactment, was that this would do away with (or at least drastically downscale) judicial discretion in the interpretation and application of the law. 45 See Leibniz’s statement of the three requirements for a new legal corpus in the Nova methodus, II, 21 (A VI/1 306–7) and his 1668 project for a systematic reformulation of Roman law, Ratio corporis juris reconcinnandi (A method for restoring the body of law), probably written with Lasser (A VI/2 93–113). On Leibniz’s codification projects, see Berkowitz (2005). 46 The model for this endeavour is clearly the system of the sciences set out by the so-called Herborn encyclopaedists, and especially by Johann Heinrich Alsted in his 1630 Encyclopaedia. Alsted is mentioned in the Preface to the Specimen (another important Herborn philosopher, Johannes Althusius, is mentioned in On Perplexing Cases, I and IX). On the influence the Herborn encyclopaedists had on Leibniz, see Loemker (1961). 47 Dissertatio de arte combinatoria, 39 (A VI/1 189, L 82). Introduction xxi

These passages provide further evidence of Leibniz’s precocious originality. For they entail the unconventional view that no case, no matter how difficult and perplexing, should be deemed insoluble: every case must admit of a solution ex jure (directly derived from the law), and indeed it will do so, if only the powers of rational thinking are applied to it. This view is nicely exemplified in Leibniz’s account of the well-known case of Protagoras v. Euathlus in Question XII of the Specimen.48 This was traditionally considered the quintessential insoluble case, since Protagoras’s argument (namely, that he would win no matter how the judges decided) also applied to his pupil Euathlus.49 The facts of the case are as follows. Protagoras and Euathlus made an agreement under which Protagoras would be Euathlus’s teacher on the condition that Euathlus would pay him on winning his first case. Time passed and Euathlus did not take any case. Protagoras thus sued Euathlus to claim his credit. Here are the arguments the two parties put forward before the judges: Protagoras. If I win the case, then in accordance with the ruling, Euathlus will have to pay me. If Euathlus wins the case, then he will have won his first case and will thus have to pay me under the terms of our contract. In either event, Euathlus will have to pay. Euathlus. If I win the case, then in accordance with the ruling, I won’t have to pay Protagoras. If Protagoras wins the case, then I will not have won my first case and will therefore owe him nothing under the terms of our contact. In either event, I will not have to pay. One of Leibniz’s sources (Gellius’s Attic Nights) tells us that “the judges, thinking that the plea on both sides was uncertain and insoluble, for fear that their decision, for whichever side it was rendered, might annul itself, left the matter undecided and postponed the case to a distant day” (V.10). Leibniz’s solution is that the judges could have ruled most equitably as follows: “You will win, Euathlus. This means that you will certainly win in this lawsuit that the master brought against you, when the condition of your contract was not yet satisfied, so that now you certainly don’t have to pay him anything, since of course he was repelled by the plea that he made an excessive claim. In the future, however, he will not lack a cause of action against you in order that you pay, given that the condition of the contract is fulfilled, since you have now won.” In this way the judges could respect both natural equity and strict law at the same time, since independently of the subtleties of the contract, gratitude is certainly due to the master.

48 This case is discussed in connection with the logico-metaphysical question “whether two contradictory propositions can simultaneously be false, that is, whether being and non-being admit a middle [...] of negation.” 49 It stands to reason that in the rhetorical tradition of antiquity this kind of argument should have been described as ἀντιστρεφoντα, or “reversible” (Latin reciproca), since the argument “implies the reversibility of the reasons provided by the two adversaries” (Calboli Montefusco 2010: 369), and this is why they are also referred to as “boomerang arguments.” xxii Introduction

In On Perplexing Cases, XVI, Leibniz further elaborates his solution: my view [is] that this case is wrongly classed among the perplexing ones. In fact, the polity in which this question is discussed punishes he who asserts a claim before the proper time. It does so either by finding against that party in the action – as the Romans once did [...] – or [...] by rejecting the claim, according to the law of nations, and as is customary today. In the first case Protagoras would be defeated, in the second he would win. In fact, since Protagoras asked his disciple to pay before the credit existed and could be claimed, and before the condition was fulfilled (the condition for payment is in fact victory in the first lawsuit), he will no doubt be considered as having made an untimely claim. Therefore, the lawsuit for this claim is lost in the first round, and owing to this very fact, the condition for payment is satisfied, since in this way Euathlus won his first lawsuit. Consequently, Protagoras now really has a cause of action against Euathlus, one no longer liable to any exception, not even the exception that the issue has already been adjudged, since Euathlus has not been absolved from the lawsuit, but only from the earlier claim, through an exception that is not peremptory but dilatory. In this way equity and strict law are joined together, for when there is doubt, it is the teacher’s case that ought to be favoured. Thus, the old controversy ceases to be a perplexing case and proves to be amenable to a solution ex mero jure (on grounds of mere law). Indeed, Leibniz’s view is that all legal cases should be so decided – or, in his own words, that “there is no lawsuit to which law cannot be applied, as there is no disease that rejects absolutely every medicine” – despite the uncertainty inherent in the interpretation of positive laws or in the welter of common opinions.50 For positive laws rest on civil reason, which limits the law of nature and of nations by way of an exception, and more particularly a restriction. Therefore, the law of nature and of nations will hold in a given case so long as it is not proved that the contrary has been introduced through statute [...]. And indeed, if the interpretation is uncertain, we must resort to the interpretive rules of natural reason, and even if the rules and presumptions give equal support to both parties, we must find against that party that grounds his claim in some positive law but cannot sufficiently establish that this law has been enacted. Thus it becomes clear that everything can in effect always be decided on the basis of the mere law of nature and of nations, under which nothing is uncertain (Section XI). Perplexity is thereby blotted out. There are, at bottom, no truly perplexing cases.

The Consilience Between Natural Law and the Laws of Nature

The conviction that positive laws are established on the basis of natural law was destined to develop in important ways in Leibniz’s legal thinking by the end of the 1660s. For the moment, it is enough to inquire into Leibniz’s grounds for his belief in the certainty of natural law. To this end, we have to again turn to the Specimen.

50 Of course, only much later, in Article 4 of the Code Napole´on of 1804, would the principle be set forth under which the judge cannot refuse to decide “under pretext of the silence, of the obscurity, or of the inadequacy of the law.” Introduction xxiii

In Question III, Leibniz offers a geometrical analysis of the rule that in order for a ditch not to damage a neighbouring estate, its distance from the estate’s border should not be inferior to its depth. Leibniz starts out in his reasoning by considering that a body which cannot fall in a straight line, can, however, descend obliquely very easily, if it forms an angle wider than 45 (with the way or line of descent) with the ground on which it sits; if the angle is narrower, [the body] will descend very uneasily and very slowly, since the more oblique and narrower the angle, the more it is necessary that the body in descending should lean sideways, which, however, is against its nature. He then devises the following Gedankenexperiment. Let a ditch be dug perpen- dicularly, close to the neighbouring estate, and let d and r be its depth and its distance from the border, respectively. Suppose that the ditch is filled with water and that for some time new water is added as its level decreases. In this situation, the level will remain about constant, but as the rate of outflow increases, the water will seep obliquely into the side of the ditch, edging toward the neighbour’s estate. However, on account of what has just been said about the inclination of an obliquely descending body, the water will seep at an inclination 45. From this it follows that if r  d, then the water will not cross the boundary into the neighbouring estate. On the contrary, if the estate of the neighbour began within the sphere of activity of the water [...] it is clear that the water [...] would come into the estate of the neighbour, and it would ruin the soil by washing it away, and having destroyed the ground [...], it will cause the earth of the neighbour [...] to encroach on my estate by sliding in the opposite direction, in such a way as to fill the hole [...]; and so my utility will harm another, and another’s damage will benefit me, which is contrary to the law of nature [...] in which, on that account, this law appears to be grounded. As contrived as the argument may seem, it reveals that what Leibniz had in mind was not a mere analogy,51 but a close correspondence between the reasons of law and the laws of nature, thanks to which natural law would become scientifically knowable.52 This is borne out by Leibniz’s treatment of the case concerning equally well-grounded conflicting claims in Theorem 271 of Doctrina conditionum.53 “This theorem,” Leibniz writes, “has been subtly deduced from natural law itself (ex ipso iure naturae) by the old jurists [...]. Indeed, this matter contains a sort of physical principle drawn from the nature of movement”

51 Compare Question IV of the Specimen, where Leibniz writes of “an elegant analogy [...] between possession and the position or location of bodies in a place”. 52 The idea may have been drawn from Erhard Weigel. In Question XVI of the Specimen, Leibniz mentions Weigel’s distinction between the “three highest genera of entities [...]: natural, moral, and notional,” each of which characterized by quantity, quality, and action, as well as the close connection Weigel saw between ethics and mechanics: “He thus reduces rights to moral qualities, and just as space is the substrate to natural action or motion, so the State is in a way a moral space, in which something like a moral motion is effected.” 53 The final version of De conditionibus (see Sect. 6 below). This line of thought is also pursued by Luig (2008: 188–89). xxiv Introduction

(A VI/1 392). Leibniz’s proof proceeds as follows. Let B and C be two bodies simultaneously striking with equal force a third body, A, along the trajectories of lines BA and CA, respectively (see figure below).

Leibniz’s figure (A VI/1 392)

Let angle BAC be bisected by line AD in the direction opposite to the two moving bodies B and C, and let AE and AF be the prolongations of BA and CA to E and F, respectively. The claim is that A will move along line AD. For, given that the body being pushed moves along the prolongation of the line drawn by the pushing body (AE and AF), if A were pushed only by B, it would proceed in its movement along line AE, whereas if it were pushed only by C, it would proceed along line AF. But since B and C concur, it follows that: (i) A will not remain motionless, for it is being pushed in one and same direction, and that by more than one body; (ii) A will not move along either lines AE or AF, for B and C exert an equal force, and since nothing happens without a cause, there is no reason why A should move along line AE rather than along line AF; (iii) much less will A move along both lines AE and AF, for nothing can be in more than one place at the same time; and finally (iv) A will not move anywhere between AE and AF other than along line AD, for there is by definition no intervening force that would cause A’s trajectory to deviate from the line bisecting angle EAF. Therefore, A will only move along line AD. And now the legal application: The concurrent [competing] parties correspond to movements BA and CA. The object of the concursus [the object of their competing claims] corresponds to the inclination of the line of the movement of A towards the concurrent lines [i.e., AE and AF]. This inclination is the greater the smaller is the angle [with A], since when the inclination is maximal the angle is null, but the movement of A and the movement of either of the pushing bodies are on a single straight line, which is what happens when one of the pushing bodies pushes alone without the concourse of the other. This corresponds in the law to the acquisition of a thing (consecutio solidi), and of the absolutely greatest part of the thing, i.e., of the whole, when no other [claim] concurs. In fact, he who does not concur obtains the absolutely smallest part of the thing, i.e., nothing. Now, just as in the movement the inclination divides among several concurrent lines – when the actual force is uniform, the movement of the body being pushed has, with respect to the movements of the pushing bodies, an angle and an inclination that are equal on both sides – so in the same way in the law, when several parties are joined with respect to one and the same thing on equal grounds, the thing is divided in such a way that each party is assigned an equal portion (A VI/1 393). Introduction xxv

This parallel between law and physics is perfectly in keeping with the philosophical and scientific approach to law developed both in the Specimen and in On Perplexing Cases, and shows that Leibniz considered natural law a source of certainty by virtue of its correspondence with the intelligible (i.e., lawful) order of the natural world.

Jurisprudence as Geometry: Leibniz’s Combinatorial Approach to Law

Leibniz’s view that all legal cases can be decided with certainty largely rests on his belief in the certainty of natural law. But there is more. That view also rests on the similarity he saw between geometry and jurisprudence.54 In De arte combinatoria, that similarity is explained in the following way: both have elements and both have cases. The elements are simples (simplicia); in geometry figures, a triangle, circle, etc.; in jurisprudence an action, a promise, a sale, etc. Cases are complexions (complexiones) of these, which are infinitely variable in either field. Euclid composed the Elements of Geometry; the elements of law are contained in the Corpus Juris [...]. To us it seems thus: the [simple] terms from whose complexion there arises the diversity of cases in the law are persons, things, acts, and rights (A VI/1 189, L 82). The idea that law had to be approached more geometrico was not in itself new.55 What was new is Leibniz’s insistence on applying the combinatorial method to calculate all possible legal cases and rules out of a set of simple elements. Leibniz recommends his method as a means for removing the uncertainty of legislation, and with it judicial discretion. Here is Leibniz’s best-known example of a jurispruden- tial application of this method. He considers the case of a mandate (gratuitous agency), namely, the contract through which an agent (a) agrees to gratuitously transact one or more affairs for the principal (p), possibly involving a third party (t). According to the Roman jurist Gaius, this gives rise to five legally relevant cases, depending on whether the mandate is contracted in favour of (1) only p; (2) both p and a; (3) only t; (4) both p and t; or (5) both r and t. Now, according to Leibniz’s rule of combinatorial calculus,56 there are seven complexions, or possible combina- tions, of m, r, and t: three unary combinations, i.e., (p), (a), and (t) with (p) and (t), corresponding to cases (1) and (3), respectively; three binary combinations, i.e., (p, a), (p, t), and (a, t), corresponding to cases (2), (4), and (5), respectively; and one ternary combination, i.e., (p, a, t). As Leibniz notes, the case corresponding to (a)is explicitly rejected by Gaius as legally irrelevant, for if the mandate is exclusively in favour of the mandatary (the agent) it does not give rise to any obligation, whereas (p, a, t), corresponding to the case in which the mandate is in favour of

54 This similarity had already been emphasized by Leibniz in On Perplexing Cases, II, through a reference to Weigel’s Analysis Aristotelica. 55 See Sect. 2 above. 56 As specified in table אּ of } 3ofDe arte combinatoria (A VI/1 174, L 79). xxvi Introduction all three parties, is simply neglected for reasons that Leibniz admits elude him (A VI/1 177, L 81). As a demonstration of the jurisprudential significance of his method, this example may look disappointing.57 More importantly, the method suffered from serious limitations, the most serious of which, as Leibniz knew all too well, was the difficulty involved in computing and assessing the huge number of possible combinations of simple elements. In fact, by the time of his collaboration with Lasser, Leibniz would have turned his early and tentative reflections into an ambitious plan for the rational systematization of the entire body of positive law on the basis of natural law.58

The Jurist’s Compass: Leibniz’s Doctrine of Natural Law

Until that time, the Nova methodus represented Leibniz’s most comprehensive attempt at resting the law on a firm rational footing and providing jurisprudence with a “solid method” (A VI/1 300) by which all legal matters could be derived from a set of basic elements. But it would be wrong to see in that work an essentially foundationalist endeavour. As a plan for legal education, Leibniz’s “new method” was primarily aimed at training the ideal or “perfect” lawyer by

57 The missing case had in fact been already detected by the twelfth-century Italian jurist Johannes Bassianus using a simple listing of the possible cases (Berkowitz 2005: 37). Boucher sees Leibniz’s example as possibly leading to “a kind of reductionism” (Boucher 2008: 237–38). Indeed, Leibniz’s method is highly significant as the first attempt to use a combinatorial technique for identifying gaps in the law (consider in this regard the use that in recent decades has been made of similar ideas in legal theory and in the development of artificial intelligence and law). However, when in the Nova methodus Leibniz mentions the legal application of his combinatorial art, it is not this example that comes up but another one (see note 59 below). 58 In a letter to Hobbes of July 1670 (A II/1 56, L 106), Leibniz mentions “a work on rational jurisprudence on which I am collaborating with a friend.” In the same letter he also remarks that his early attempts were prompted by his having “realized that a large part of [the solutions provided by the Roman jurisconsults] were arrived at almost entirely by demonstration from the law of nature alone”. He traces his first attempts back to De arte combinatoria: “When I first set my feet in the paths of jurisprudence, therefore, I began 4 years ago to work out a plan for compiling in the fewest words possible the elements of the law contained in the Roman Corpus (in the manner of the old Perpetual Edict), so that one could, so to speak, finally demonstrate from them its universal laws”. Interestingly, Leibniz recognizes here the difficulty of the task, but he does not set that difficulty to the limitations of the combinatorial method. He instead offers this explanation: “There are many laws which will prove refractory to this method, especially in the Imperial Rescripts, because they do not belong to natural law.” In spite of this, Leibniz optimisti- cally concludes that “these [laws] are clearly discernible among the rest and will be counter- balanced by the multitude of the others – especially since I venture to assert that half of the Roman law is mere natural law” (A II/1 57, L 106; an analogous statement is found in Leibniz’s letter to van Velthuysen of 6/16 April 1670, A II/1 40). As we will see, only shortly after the Mainz period will Leibniz explicitly acknowledge the difficulties of applying his combinatorial method to jurisprudence. On Leibniz’s work in the Mainz period and the developments beyond it see Sect. 7, and note 80 in particular. Introduction xxvii equipping him with a vast array of theoretical and practical skills. Specifically, he envisioned a didactic or positive jurisprudence meant to impart the required legal knowledge organized according to the elemental method, and a polemic jurispru- dence meant to help the lawyer steer his course in the perilous waters of legal cases, a task to be accomplished by equipping the lawyer with the “compass” of natural law (A VI/1 341).59 Indeed, Leibniz contributes two “principles of decision” to legal practice: natural law and legal analogy, the latter closely related to the law’s political dimension. “It is therefore apparent,” he argues, “that the jurist sitting in the courtroom has two eyes: the science of natural law and the nomothetic science” or the science of politics (A VI/1 342).60 In this context, Leibniz offers his most refined treatment of natural law, which was meant to reconcile the views of the ancients with those of the moderns.61 To this end, he distinguishes three degrees of natural law – namely, strict law (ius strictum), equity, and piety – hierarchically arranged along a scale of perfection, each degree being more perfect than the lower one, each imparting its perfection to that lower degree, and having an overriding force in cases of conflict (A VI/1 343).62 The first degree of natural law, namely,

59 These two areas (didactic and polemic jurisprudence) made up only half of Leibniz’s model for the study and practice of law: the other half consisted of historical and exegetic jurisprudence, the latter involving the legal application of certain disciplines, namely, grammar, rhetoric, ethics, politics, logic, metaphysics, and physics, in which regard Leibniz refers to the Specimen and to a future treatise on Legal Philology and Philosophy (A VI/1 324). Leibniz recognizes in particular the need for a legal geometry and a legal arithmetic, examples of which are, respectively, Question III of the Specimen and the determination of the degrees of consanguinity in Problem III of De arte combinatoria (A VI/1 327). 60 This means that the jurist must not only be guided by the highest norms of natural justice but must also take into account the actual conditions of society, a thought which Leibniz would entertain for the rest of his life, and which goes hand in hand with his insistence on the relativity of positive laws as opposed to the perpetuity of natural law. See Leibniz’s much later statement of this view in his 1695 note from the Elementa juris perpetui (Elements of eternal law) in G 637–79. Significantly, one of the projects announced in the Nova methodus is for a “Legal Theatre” in which the legal issues involving all peoples, places, and times would find their place in a “parallel” exposition (A VI/1 314). 61 This is probably the first clear illustration of the characteristically conciliatory method by which Leibniz sought to contribute to putting an end to the tribulations of his time, by showing how even the most irreconcilable views were so only in appearance and could actually be made to peacefully coexist. See also Leibniz’s vision for an “Irenic History” containing all the attempts at reconciliation made by both Protestants and Catholics, a history the jurist will have to know in order to understand and judge all opinions without “fulminating” against any doctrinal or ritual disagreement (A VI/1 314). 62 To fully appreciate the significance of this development, compare it with Leibniz’s crude treatment of natural law in Question VIII of the Specimen. The three-degrees doctrine of the Nova methodus would become central to Leibniz’s later accounts of natural law. Versions of it occur in his notes on the elements of natural law from 1677 to 1678 (G 616–67) and in Sections XII–XIII of the Preface to the Codex juris gentium diplomaticus (Diplomatic code of the law of nations) of 1693 (R 171–4; see Leibniz’s explicit reference to his youthful work on p. 173). Leibniz once again went back to his three-degrees doctrine in the years 1695–1697, when he undertook to set out a systematic exposition of his lifelong work on natural law (see G 636, 639) with a revised edition of the Nova methodus. An echo of this doctrine can also be spied in Leibniz’s late Meditation on the Common Concept of Justice, written around 1702–1703 (R 60). xxviii Introduction strict or pure law, “follows from the definition of the terms” and takes as its core precept the first basic principle of Roman law, neminem laedere (do no harm). This for Leibniz was the lowest form of justice, the kind Aristotle called commutative justice. The middle degree of natural law, equity, “or equality, that is, the ratio or proportion between two or more, consists in harmony or congruence”63 and takes as its core precept the second basic principle of Roman law, suum cuique tribuere (give everyone his due), corresponding to Aristotle’s distributive justice.64 Finally, piety takes as its core precept the third basic principle of Roman law, honeste vivere (live honorably). As the highest degree of natural law, piety “gives the other degrees perfection and execution” (A VI/1 344). How such a degree of perfection can be achieved is a genuine problem, considering that, as Leibniz acknowledges, “strict law and equity lack a physical bond,” which makes rather problematic his original belief in the possibility of grounding natural law in its correspondence with physical laws. Leibniz’s solution is that piety binds strict law to equity by virtue of its being grounded in God’s will. This, however, does not imply any (strict) voluntarism. For power, in God, necessarily conforms to wisdom: it does so by integrating different orders of reality, in a way that clearly foreshadows Leibniz’s later divinely preestablished harmony between the two kingdoms of power and wisdom, or between the physical realm of nature and the moral realm of grace: For God, being omniscient and wise, upholds pure law and equity; and, being omnipotent, He carries them into execution. Thus the utility of mankind, and indeed the beauty and harmony of the world, coincide with God’s will [...]. God by his intervention makes it so that anything of public utility, that is, anything useful for mankind and for the world, is also useful for each one individually; accordingly, everything honest is useful, and everything base is harmful. Since it is evident from God’s wisdom that He assigned a reward to the just and a punishment to the unjust, and it is demonstrated by reason of his omnipotence that he will accomplish what he has assigned. Therefore, the existence of a wisest and most potent Being, that is, God, is the ultimate grounds of natural law (A VI/1 344–45).65

63 This definition of equity as geometrical equality or proportion was previously found in On Perplexing Cases, XXVII. 64 The identification of the second degree of natural law with distributive justice is made explicit in later writings (especially those mentioned at note 62 above). 65 Compare this passage with the following passage from Leibniz’s Principes de la nature et de la graˆce fonde´s en raison (1714): “That is why all minds, whether of men or genies, entering into a kind of society with God by virtue of reason and eternal truths, are members of the City of God, that is, members of the perfect state, formed and governed by the greatest and best of monarchs. Here there is no crime without punishment, no good action without proportionate reward, and finally, as much virtue and happiness as is possible. And this is accomplished without disordering nature (as if what God prepared for souls disturbed the laws of bodies), but through the very order of natural things (par l’ordre meˆme des choses naturelles), in virtue of the harmony pre- established from all time between the kingdoms of nature and grace, between God as architect and God as monarch. Consequently, nature itself leads to grace, and grace perfects nature by making use of it” (G VI 605, AG 212). Incidentally, this passage not only validates Christia Mercer’s thesis that Leibniz came up with his doctrine of preestablished harmony before the end of the Mainz period (see Mercer 2001: 2, 18, 252, 300–301) but locates that doctrine at the beginning of this period. Introduction xxix

In addition to the principles of decision, a lawyer will also be able to access a systematic collection of legal decisions or legal controversies arranged according the elemental order. “The elements, in fact, must be ordered in the mathematical style (more mathematico) in such a way that all matters could be decided on their basis” (A VI/1 346). Leibniz offers no example of this. Instead, he suggests a straightforward application of a crude symbolic notation to various kinds of legal arguments in analogy to Isaac Barrow’s symbolic treatment of Euclid’s Elements.66 Finally, having illustrated his plan for restructuring the study of law, Leibniz closes his book by portraying a graduate student upon completing his proposed 2-year law course, a portrait that for him sums up all the characteristics of the ideal lawyer: He will settle controversies by his judgment, and tandem custode remoto, in apricis gramine campi,67 he will fly across the law’s wide expanse, perusing the authentic law books and the articles and laws, which will initially be most necessary, and after that he will gradually add other things to the assigned book just praised. From this he will extract what is needed to decide various controversies, and he will craft new rules and new universal principles that others have overlooked; he will use commentaries and will penetrate into the reasons behind the laws and will gradually acquire the prudence of a legislator. Then, having advanced through the wide sea of controversies, he will observe the customs of the courts and the judgments handed down by the forebears. He will notice those conflicts, disagreements, and changes in the laws that are dependent on national character and on the differences among states. And he will learn to deduce chains of firm demonstrations from the unchanging principles of natural law in the public interest, and to brandish the sword of invincible science to cut through the empty subtleties and laughable allegations of the practitioners of law, and through the tangled knots deriving from the doctors’ purported authority and inappropriate use of brocards. This I will call a true philosopher of law, a priest of justice, and an expert in the law of nations and in what depends on it, and in both civil and divine law (A VI/1 362).

The Close of an Epoch: Leibniz’s Specimina juris

The 1669 publication of Specimina juris can be said to mark the close of the early part of Leibniz’s career as a jurist. The book organizes Leibniz’s early legal works in a systematic treatise. This systematizing effort is suggested by the order in which the dissertations are presented and by the changes made to their titles. In fact, the De casibus perplexis comes first, under the title Specimen difficultatis in jure,

66 I. Barrows, Euclidis Elementorum Libri xv breviter demonstrati, first published in 1654. Barrow was Newton’s teacher and his predecessor as holder of the Lucasian Chair of Mathematics at Cambridge University. And in fact Leibniz seems to foreshadow here just that kind of “formal calculus capable of offering an incontestable ‘mechanical’ decision procedure [...] for all litigations,” a calculus that according to Dascal (Leibniz 2008: 66) would be missing in later writings on the same topic (see ibid., 66–68). 67 Here Leibniz quotes Horace’s Ars poetica from memory. The actual verses (161–62) read: “Inberbis iuvenis, tandem custode remoto/gaudet equis canibusque et aprici gramine campi” (“The beardless youth, free of tutors at last, delights./In horse and hound, and the turf of the sunlit Campus”). xxx Introduction seu Dissertatio de casibus perplexis (Specimen of difficulties in law, or dissertation on perplexing cases); next comes the Specimen under the title Specimen Encyclopediae in jure seu Quaestiones philosophicae amoeniores, ex jure collectae (Specimen of a legal encyclopaedia, or most delightful philosophical questions collected from the law); and finally at the end comes the De conditionibus under the title Specimen certitudinis seu demontrationum in jure, exhibitum in Doctrina conditionum (Specimen of certainty or demonstrations in law, exhibited in the doctrine of conditions). As Marcelo Dascal has noted, the significance Leibniz attaches to the different essays is emphasized by the different font sizes used in the book’s title page (A VI/1 367),68 the title of the first essay being the largest and that of the third the smallest. Dascal argues on this basis that the last two essays were understood by Leibniz as an illustration of “the kinds of considerations or tools capable of contributing to eventually solving difficulties such as those discussed in the first” (Dascal 2008: 49). This is probably correct. In fact, everything we have said in the preceding sections supports the conclusion that Leibniz’s intention was to offer a definitive statement of his method for attaining certainty in law with the help of philosophy and other disciplines, working up to the absolute certainty attainable in those parts of the law that lend themselves to being set on solid demonstrative grounds. Leibniz had already identified those parts of the law with the doctrine of legal conditions, the subject of his 1665 dissertation (also central to On Perplexing Cases).69 From 1667 to 1669, he rearranged this work completely. The result was the Doctrina conditionum. As the title suggests, Leibniz’s aim was to offer an “example” of how the demonstrative method applied to the law, an example for which he turned to that part of Roman law which deals with various kinds of legal conditions. Indeed, the notion of a conditional provision (for example, a provision that makes the performance of a promise dependent on a future and possibly uncertain fact), that was central to contract law and to the law of wills, is by its very nature amenable to inferential treatment.70 Leibniz’s construction develops through definitions and theorems derived from those same definitions by substitution of definitional equivalents. Unfortunately, the construction breaks down at various points. For example, the previously discussed Theorem 271 is not inferred from the definitions but receives “some kind of demonstration” that is not as strong as the kind obtained by geometrical proof.71 Other theorems are left without demonstration simply because no reason can be

68 Resort to such typographical tricks had previously been mentioned in the Nova methodus (A VI/ 1 308, 355–56), where Leibniz presents this as a useful device. 69 Especially as concerns Sections XIII–XVII. 70 This point is clarified in Vargas (2008). 71 “...genere quodam demonstrationi simul illustrante et probante” (A VI/1 392), as Leibniz says, i.e., a demonstration which at the same time “elucidates” and “proves” in a weak sense. Introduction xxxi given for them.72 Despite these shortcomings, Leibniz is quick to generalize his approach to the entire science of law: The doctrine of Right belongs to those sciences which depend on definitions and not on experience and on demonstrations of reason and not of sense; they are problems of law, so to speak, and not of fact. For since justice consists in a kind of congruity and proportionality, we can understand that something is just even if there is no one who practices it or upon whom it is practiced. Just so the relations of numbers are true even if there were no one to count and nothing to be counted, and we can predict that a house will be beautiful, a machine efficient, or a commonwealth happy, if it comes into being, even if it should never do so. We need not wonder, therefore, that the principles of these sciences possess eternal truth. For they are all conditionalia, conditional truths, and treat not of what does exist but of what follows if existence be assumed.73 Although Leibniz would never again engage in both the study of legal conditions and the analysis of conditional propositions (Couturat 1901: 554), this statement speaks to how his views at the beginning of the Mainz period were already developing in a way that brings them very close to his mature conception of legal science as a science of eternal truths on a par with arithmetic and geometry.74

A Glance at the Mainz Years: Law, Justice, and Logic

The plan for a rational ordering of the entire body of law lies at the heart of Leibniz’s work during the Mainz period. In his famous letter to Antoine Arnauld of November 1671, he describes his work as follows: I am working on a Nucleus of Roman Laws, which presents in its own words, concisely and in good order, that which is truly law in the entire Corpus [...]. In addition, I am thinking of recapitulating the Elements of Roman Law in a short table which presents, at a single glance, the few clear rules the combination of which can solve all cases, and furthermore, new arguments for abridging lawsuits [...]. In addition to these, I am planning to treat the Elements of Natural Law in a short book in which everything will be demonstrated from definitions alone. For I define a good or just man (virum bonum seu justum) as one who loves everyone; love as pleasure taken in the happiness of others, and pain in the unhappi- ness of others; happiness as pleasure without pain; pleasure as the sense of harmony; pain as the sense of disharmony; sense as thought with will or with a conatus to act; harmony as diversity compensated by identity [...]. From these I deduce all the theorems of right and equity (juris et aequi). That is permissible (licitum) which is possible for a good man. That is duty (debitum) which is necessary for a good man. Hence it is clear that the just man, the man who loves all, necessarily strives to please all, even when he cannot do so, much as a stone strives to fall even when is suspended (A II/1 173–4, L 149–50).

72 As Boucher (1998: 30) has noted, that is the case with Theorem 49, for it implies a conflict between strict (positive) law and equity. 73 Elementa juris naturalis (1670–1671), A VI/1 460, L 133. The characterization of conditional truths given here follows from their being hypothetical propositions (A VI/1 370). 74 A similar statement appears in Meditation on the Common Concept of Justice (R 49–50). xxxii Introduction

As Leibniz himself wrote in a subsequent letter, he was working on the Nucleus of Roman Laws as assistant to Lasser, whereas the Elements of Roman Law and the Elements of Natural Law were his own contribution.75 Leibniz’s work on the elements of natural law is documented by a series of notes from 1669 to 1671 (A VI/1 430–85). These notes and the passage just quoted from the letter to Arnauld make it possible to conjecture that not until 1671 did the watershed moment materialize in Leibniz’s mind, i.e., only after he had significantly improved the doctrine of natural law expounded in the Nova methodus. In fact, the definition of the good or just man76 found in that letter gives clear expressions to the idea of justice as love that Leibniz had just arrived at.77 Leibniz’s suggestion is that this definition, in combination with a few other ones (of love, happiness, pleasure, pain, sense, and harmony), can provide the basis for working out all propositions about what is right and equitable. But he does not just make the suggestion: he also sets out to show how the project might actually be carried out, and in so doing he clearly anticipates much of modern deontic logic. This can be seen from his notes for the book he planned to write on the elements of natural law, especially those from the first half of 1671 (A VI/1 465–480). This section begins with Leibniz’s novel definition of justice as “the habit of loving everyone.” Next come the definitions of (a)theiustum, licitum (just, permissible); (b)the injustum, illicitum (unjust, impermissible); (c)theaequum, debitum (equitable, oblig- atory); and (d)theindebitum (non-obligatory) as referring to those actions which for a good man (one who loves everyone) are (a)possible,78 (b) impossible, (c)necessary, or (d) omissible, respectively. These are the elements or the legal modalities (iuris modalia), which need to be explored in their mutual combinations, as well as in combination with other modalities and with the definition of the good man.79 This gives rise to four lines of inquiry. The first two line of inquiry lead to such basic principles of deontic logic as “Nothing permissible is impermissible”

75 Leibniz to Ferrand, 31 January 1672 (A I/1 181). As this letter reveals, along with other writings from this period, the codification project included a fourth part, the “Body of Roman Law,” for which Lasser was responsible. As is suggested by Leibniz’s 1670 letter to Hobbes (see note 58 above), the elements of Roman (or civil) law may have been the first contribution Leibniz planned to make to the project. Also supporting the same conclusion is the letter Leibniz wrote to Conring on 13/23 January 1670 (A II/1 31). The preserved drafts are from the years 1668–1671 (G 705–21). In any case, the project for a Juris naturalis elementa demonstrative tradita had already been included in the list of desiderata that closes the Nova methodus (A VI/1 364). 76 Originally a notion of Roman law. See, e.g., Doctrina conditionum, Tr. 61 (A VI/1 419). 77 On the evolution of Leibniz’s concept of justice from the Nova methodus (justice as power tempered by wisdom) to the end of the Mainz period (justice as universal love), see the classic article by Mulvaney (1968), which also discusses Leibniz’s letter to Arnauld (on p. 71). Leibniz’s definition here directly preludes his final, and most famous, definition of justice as the “charity of the wise.” On this question, see Riley (1996). 78 See Question XVI of the Specimen, especially note b. 79 Leibniz actually calculates the sum total of all possible combinations that could be formed “from the mere definition of a good man”: it all computes to 1,485,600 combinations! And that clipping the “everyone” from the predicate “who loves”, for otherwise it would have been necessary to enumerate every single individual on the planet (A VI/1 478). Introduction xxxiii

(Nullum justum est injustum) and “Everything obligatory is possible” (Omne debitum possibile est). The third line of inquiry consists in the attempt to combine the legal modalities with judgments of probability. The main theorem here is given by the assertion that it is easier (i.e., more likely) for an act to be just than unjust (Actus facilius est justus quam injustus), with the corollary that an act must always be presumed to be just (Actus praesumitur justus). Finally, the fourth line of inquiry provides a system for combining legal and alethic modalities with the definition of the good man. Leibniz lists the following theorems, among others: “Everything permissi- ble is possible for one who loves everyone” (Omne justum possibile est amanti omnes); “Everything obligatory is necessary for one who loves everyone” (Omne debitum necessarium est amanti omnes), and “Everything impermissible is impossible for one who loves everyone” (Omne injustum impossibile est amanti omnes). Seen from the vantage point of modern deontic logic, this fourth line of inquiry looks like an explicit attempt at reducing deontic logic to alethic modal logic through the definition of a good man (Hilpinen 2001: 159). From Leibniz’s point of view, this endeavour marks an important change of direction in his lifelong search for legal certainty, his focus shifting from the initial “art of forming cases” to a legal science capable of deriving the entire system of law from its very source in the highest form of justice.80 Here is how Leibniz prefigures the scope of such a science, having just laid out the building blocks of his deontic system: Jurisprudence is the science of the just, i.e., the science of freedom and duties, or the science of law, given some case or fact. I call it a science, albeit a practical one, since all of its propositions can be demonstrated from the mere definition of a good man, and do not depend on induction and examples [...]. I call it a science of the just, because it shows both what is not possible for a good man do and what is not possible for him to omit. I call it a science of duties, i.e., of what is, impossible and necessary, that is, impossible to omit, for a good man, everything else being considered just and indifferent, or possible and contingent (A VI/1 467). Not unexpectedly, given the hints contained in the passage just quoted from his 1671 letter to Arnauld, Leibniz ends his notes with an analysis of love that draws on

80 The importance of this shift is witnessed by Leibniz’s writings from 1677 to 1679, especially by his second series of notes on the elements of natural law, where he seeks to combine his theory of the three degrees of natural law with the system of legal modalities based on his definition of the good man under his mature definition of justice as the charity of the wise (G 603–16). In this same period Leibniz acknowledges the problems with his early views on the “completeness” of the legal system. As he comments in a 1678–1679 draft published as De legum interpretatione, rationibus, applicatione, systemate, no system of laws such that the laws “neither conflict with each other nor leave any margin of doubt regarding any case is so far available, but in my opinion there is no doubt that it can be achieved. People tend to think otherwise, for they believe that there are infinite cases, so that to enumerate all of them is beyond human power. This would be the case if our aim were to enumerate all cases; but he who knows the universals [universalia] can easily range a countless quantity of things in classes, so that nothing remains outside”. Leibniz accordingly proposes that the complete enumeration of cases be replaced by a sort of “covering law” system in which “a few laws could cover countless cases, since countless combinations regarding the cases can be made out of a few laws” (A VI/4 2791, Leibniz 2008: 88). Still, other writings from this same period (see references in G 704) suggest that Leibniz never entirely gave up the prospect of applying the combinatorial method to the law. xxxiv Introduction the Hobbesian notion of “conatus” (endeavour or striving)81 in order to infer a number of laws of love parallel to the laws of motion,82 thus shedding new light on the correspondence he had already stipulated between the moral and physical domains.83

A Note on the Translation

Leibniz’s early works pose a special difficulty for the translator, this owing to the vast array of sources set into the text through a system of citations and references that may appear almost indecipherable to contemporary eyes (even the most cursory a glance at the Latin text will make this immediately apparent). We have sought to solve this difficulty by attempting to reconcile two desiderata: the need to adhere to the original text with the need to make for a comprehensible read. Here is a brief exposition of the more technical criteria we have adopted. For all references to Justinian’s Corpus iuris civilis, the Liber Extra (the Decretals of Pope Gregory IX), and the Liber Sextus Decretalium (Sixth Book of the Decretals issued by Boniface VIII), we have maintained the original notation in the text, while citing the source according to modern usage in the footnotes. Thus, for example, in the text the reader will find “l. (for law)84 16 } 6D. (for Digest)

81 Conatus is a twofold notion carrying both a mental and a physical sense. In the first sense, it is the “will or [...] conatus to act” (see Leibniz’s 1671 letter to Arnauld), or the “beginning of action” (A VI/1 483: conatus est initium actionis). In the second sense, as applied to bodies, conatus means the beginning of motion (see also Leibniz’s letter to van Velthuysen of May 1671, A II/1 98). Leibniz was applying this idea to the laws of motion in the very years he was developing his views on natural law. This development led to the Hypothesis physica nova (A new physical hypothesis), Leibniz’s first contribution to natural philosophy, published in 1671 (A VI/2 219–76; partial translation in L 139–42 and Leibniz 2001: 338–43). On Hobbes’s notion of conatus and its influence on Leibniz, see MacDonald Ross (2007). 82 Leibniz lays down the following laws in particular: “If several loves concur, their conatus is effective (efficax) to produce the greatest harmony that can be produced in the present state. If two loves occur, the greater prevails. But the effect is the difference of their efficacies [...]. If they are equal, the efficacy of either will be destroyed [...]. If several loves are collinear, their efficacies are compounded into one. If several equal loves concur obliquely, the product is the mean of their efficacies obliquely, that is to say in such a way that a third can be chosen [intermediate between them]” (A VI/1 479). 83 Leibniz’s final remark (A VI/1 480) seems to identify a further ground for the intimate connection between these two domains, for he invokes the notion of an ether or universal spirit (introduced in the Hypothesis physica nova) as a tool through which God would establish a perfect harmony between minds and bodies. The need to ground jurisprudence in a universal spirit and in the laws of motion is expressed in a letter Leibniz wrote to Duke Johann Friedrich on 21 May, 1671 (A II/1 106–7), that to the best of our knowledge contains the fullest statement of these ideas. 84 As was customary at his time, Leibniz uses the abbreviation l. (for lex) to refer also to passages in the Digest. Such passages are not statutes but opinions by Roman jurists, some of which were legally binding (the opinions of Ulpian, Gaius, Paulus, Papinianus, and Modestinus were recognized as having this authority in the Law of Citations issued by Emperor Valentinian III in AD 426). Introduction xxxv

De receptis qui arbitrium” and “c. (for canon) 41 De electione.” In the footnotes, by contrast, one will find the notation “D.” (for Digest), followed by book, title, law, and paragraph number, as in “D. 4.8.16.6.” The same goes for the Codex (“C.”), the Institutes (“Inst.”), and the Liber Extra (“X.”) and Sextus (“Sext.”), as in “X. 1.6.41.” When, as in the two examples in question, the title is provided by Leibniz in an abbreviated form (or else in an uncorrected idiosyncratic one) the corresponding source note will have the full (and, if need be, corrected) title in parentheses at the end. Thus, in the two examples, the footnote will read “D. 4.8.16.6 (De receptis arbitris, et qui arbitrium recipiunt, ut sententiam dicant)” and “X. 1.6.41 (De electione et electi potestate),” respectively. A selection of the passages from the Digest cited by Leibniz is found in the Annexes, where they are quoted from Watson’s translation (The Digest of Justinian, ed. and trans. A. Watson. Philadelphia: University of Pennsylvania Press, 1985). References to legal works (a massive literature spanning from the Glossators’ time to that of Leibniz) have been treated in accordance with two conventions as follows, one for names and the other for titles. 1. Authors’ names, generally mentioned by Leibniz in a Latinized form, appear in this volume in their original language (e.g., “Bachov” for “Bachovius”), this in all but a few cases where the Latinized version is the more usual form (e.g., “Venturus de Valentia” for “Valentin von Winther”). To avoid misunder- standings, the Bio-Bibliographical Note at the end of the volume reports both the original name and its Latinized version. 2. Titles of works – which, as mentioned, are usually cited by Leibniz in an abbreviated and sometimes modified form – have been left in that form, but written out without abbreviations (e.g., “Variarum resolutionum” for “Var. Resol.”). The full title and source are provided in the Bio-Bibliographical Note. Classical works, such as Grotius’ De jure belli ac pacis, are mentioned by their current English title (On the Law of War and Peace). The same goes for classical literary, philosophical, scientific, and historical works (e.g., Pliny’s Natural History). A clarification is in order concerning Leibniz’s use of the term ius, along with its cognates. The term ius refers either to the law as a whole or to particular entitlements or rights deriving from it. We have used the term law in the first case and right in the second. Leibniz distinguishes different kinds of ius. The first kind is the ius commune, namely, the legal content resulting from the doctrinal development of Roman law, which formed the basis of legal education and practice in continental Europe before the codifications. Aside from the Roman component, i.e., the ius civile (civil law), the ius commune also included the ius canonicum (canon law) of the Church. We have chosen to refer to the ius commune by its Latin term rather than by the literal translation (i.e., “common law”) to avoid confusion with the English common law. A second kind was the ius speciale, consisting of the regulations issued by contemporary political authorities like the prince elector of Hannover. For ius speciale (literally, special law) too we have stuck to the Latin term. Leibniz also mentions the ius naturale, which we have translated as xxxvi Introduction

“natural law,” and the ius gentium, which we have translated as “law of nations.” We have also maintained the term Landrecht, literally “law of the land,” referring to the law of particular German territories. Leibniz uses it only when referring to the Saxon Constitution and to one part of the Medieval Sachsenspiegel (Saxon Mirror), which comprised the Landrecht and the Lehnrecht (feudal law).