This article explores the relations between Leibniz and the French erudite Pierre-Daniel Huet in the context of their shared anti-Cartesianism. After an introductory survey of the available commentaries and primary texts, I focus on a publication by Leibniz in the Journal des sçavans from 1693, where he fully endorses the critique of Descartes developed by Huet in his 1689 Censura philosophiae cartesianae. Next, I provide some indications as to Leibniz’s motivations behind this public approval of Huet. First, I show how Leibniz throughout the 1690s was attempting to have his 1692 Animadversiones in partem generalem Principiorum Cartesianorum and other anti-Cartesian items annexed to a reedition of Huet’s Censura. I finally show how these attempts to team up with Huet were prompted by Leibniz’s dislike of certain German Cartesians, in particular J. E. Schweling, and by his fear that orthodox Cartesianism might do irremediable damage to the intellectual ethics of the Republic of Letters.

This paper traces Leibniz’s use of his neologism, “transcreation.” Leibniz coins the term in his 1676 discussions of motion, using it to identify a certain type of leap that is essential to motion. But Leibniz quickly dispensed with this theory of motion, arguing instead that “nature never acts by leaps,” and the term “transcreation” fell out of use. However, Leibniz surprisingly revived the term in 1709 in his discussion of the generation of rational beings. By contrasting the way Leibniz uses the term in his theory of motion with his use of the term in the generation of rational beings, we will see that Leibniz’s arguments against leaps early in his career are less forceful against the leaps purportedly involved in the generation of minds. Nevertheless, the “transcreation” of minds does not necessary entail a discontinuity in the “chain of being.”

The only extensive study that Leibniz ever made of an English-language book, his New Essays on John Locke’s 1690 Essay Concerning Human Understanding, was based not on the English original, but on a French translation. And his correspondence with English scholars and political figures was invariably written in Latin or French. In consequence the impression is widespread among Anglophone Leibnizians that he did not know English. However, considerable evidence has come to light in recent years that Leibniz did somehow manage to acquire a capacity to handle the language in its written form.

Most interpreters think that for Leibniz, teleology is goodness-directedness. Explaining a monadic action teleologically, according to them, simply means explaining it in terms of the goodness of the state at which the agent aims. On some interpretations, the goodness at issue is always apparent goodness: an action is end-directed iff it aims at what appears good to the agent. On other interpretations, the goodness at issue is only sometimes apparent goodness and at other times merely objective goodness: some actions do not aim at what appears good to the agent, but merely at what is objectively good—that is, at what God knows to be good—and that is sufficient for teleology. My paper, on the other hand, argues that both of these interpretations are mistaken. Monadic teleology, I contend, does not have to consist in striving for the good; neither goodness nor God is required to make monadic actions teleological.

Leibniz’s infinite-analysis theory of contingency says a truth is contingent if and only if it cannot be proved via analysis in finitely many steps. Some have argued that this theory faces the Problem of Lucky Proof—we might, by luck, complete our proof early in the analysis, and thus have a finite proof of a contingent truth—and the related Problem of Guaranteed Proof—even if we do not complete our proof early in the analysis, we are guaranteed to complete it in finitely many steps. I aim to solve both problems. For Leibniz, analysis is constrained by three rules: an analysis begins with the conclusion; subsequent steps replace a term by (part of) its real definition; and the analysis is finished only when an identity is reached. Furthermore, real definitions of complete concepts are infinitely complex, and Leibniz thinks infinities lack parts. From these observations, a solution to our problems follows: an analysis of a truth containing a complete concept cannot be completed in a finite number of steps—indeed, the first step of the analysis cannot be completed. I conclude by defusing some alleged counterexamples to my account.

It is well-known that Leibniz ends and crowns the 1714 “Monadologie” with a version of his notion of jurisprudence universelle or “justice as the charity [love] of the wise:” for sections 83-90 of the Vienna manuscript claim that “the totality of all spirits must compose the City of God . . . this perfect government . . . the most perfect state that is possible . . . this truly universal monarchy [which is] a moral world in the natural world”—a moral world of iustitia in which “no good action would be unrewarded” for those “citizens” who “find pleasure . . . in the contemplation of [God’s] perfections, as is the way of genuine ‘pure love.’” But the opening four-fifths of the work offer Leibniz’ theory of “substance” (or monad) viewed as the necessary pre-condition of justice: for “on the knowledge of substance, and in the consequence of the soul, depends the knowledge of virtue and of justice” (to Pierre Coste, 1712). Thus without a complete and correct notion of substance/monad, no complete and correct notion commune de la justice would be conceivable. Hence the entire “Monadologie” can be understood as a theory of justice underpinned by a Grundlegung of moral “monads” or justice-loving rational “substances.” In this connection it is revelatory that Leibniz cites the relevant sections of the 1710 Théodicée in most of the 90 articles of the “Monadologie” (beginning indeed with article #1): for Théodicée (theos-dike) is (Leibniz says) “the justice of God,” and Leibniz makes that justice “appear” in the opening lines of the “Monadologie” (in effect) by referring the reader immediately to Théodicée #10 (“Preliminary Dissertation”) —which relates “im­mortal spirits” to a just God who is cherished through “genuine pure love.” This means that “the justice of God” as “higher love” colors the “Monadologie” instantly. Thus one need not “wait” for sections 83-90 to arrive in order for the “Monadologie” to be(come) a “theory of justice:” it is such ab initio.

Recent scholarship has established that, until the mid-1670s, Leibniz did not hold the possibilist ontology which, in his mature philosophy, provides the foundation for both his account of human freedom and of eternal truth. Concentrating on the Mainz period (1667-1672), this paper examines the conciliation, in those early writings, of an actualist ontology and a conception of necessary truth as analytical. The first section questions the view that Leibniz was educated in a “Platonist” tradition; the second section presents the actualist metaphysics that he adopted in the wake of his teachers; the third section shows how Leibniz could, contrary to those same teachers, hold an analytical view of eternal truth, even without the support of his later possibilist ontology and doctrine of real definitions.

We argue in this paper that Leibniz’s characterization of a substance as “un être” in his correspondence with Arnauld stresses the per se unity of substance rather than oneness in number. We employ two central lines of reasoning. The first is a response to Mogens Lærke’s claim that one can mark the difference between Spinoza and Leibniz by observing that, while Spinoza’s notion of substance is essentially non-numerical, Leibniz’s view of substance is numerical. We argue that Leibniz, like Spinoza, qualifies the substance as “one” primarily in a non-numerical sense, where non-numerical means per se unity or qualitative uniqueness. The second line of reasoning suggests that the term “one” should be understood as a-unity-presupposed-by-multiplicity in two senses: a) externally, in the sense of being presupposed by higher complex structures, such as aggregates, and, b) internally, in the sense of having itself a complex structure. We develop an analogy along these lines between the role the notion of a fundamental unity plays in Leibniz’s view of numbers and his view of substance. In other words, we suggest that looking at the role units play in Leibniz’s view of mathematics can shed some light on the role they play in his metaphysics.

In this paper, I address a topic that has been mostly neglected in Leibniz scholarship: Leibniz’s conception of number. I argue that Leibniz thinks of numbers as a certain kind of relation, and that as such, numbers have a privileged place in his metaphysical system as entities that express a certain kind of possibility. Establishing the relational view requires reconciling two seemingly inconsistent definitions of number in Leibniz’s corpus; establishing where numbers fit in Leibniz’s ontology requires confronting a challenge from the well-known nominalist reading of Leibniz most forcefully articulated in Mates (1986). While my main focus is limited to the positive integers, I also argue that Leibniz intends to subsume them under a more general conception of number.

The question of Leibniz’s relationship to mysticism has been a topic of some debate since the early part of the 20th Century. An initial wave of scholarship led by Jean Baruzi pre­sented Leibniz as a mystic. However, later in the 20th Century the mood turned against this view and the negative appraisal holds sway today. In this paper I do two things: First I provide a detailed account of the ways in which Leibniz is critical of mysticism; second, I argue that there is, nonetheless, an important sense in which Leibniz should be regarded as an advocate of mysticism. However, the approach that I take does not focus on an effort to overturn the kinds of considerations that led people to reject the views of Baruzi. Instead, I try to reframe the discussion and explore more complex and interesting relationships that exist between mysticism and Leibniz’s philosophical theology than have been articulated previously. Here I draw on some recent discussions of mysticism in the philosophical literature to illuminate Leibniz’s own distinction between “false mysticism” and “true mystical theology” and his assessment of the views of a number of other people who might plausibly be identified as mystics.

The question why Leibniz continues to fascinate and perplex us 300 years after his death is one I approach with both hesitation and enthusiasm. Rather than attempting a survey of currrent controversies in Leibniz scholarship, as useful and interesting as such a survey would be, I take the opportunity to explain the underlying basis of our interest in Leibniz.