This chapter examines the pioneering work of Gottfried Wilhelm Leibniz (1646-1716) on various number systems, in particular binary, which he independently invented in the mid-to-late 1670s, and hexadecimal, which he invented in 1679. The chapter begins with the oft-debated question of who may have influenced Leibniz’s invention of binary, though as none of the proposed candidates is plausible I suggest a different hypothesis, that Leibniz initially developed binary notation as a tool to assist his investigations in mathematical (...) problems that were exercising him at the time, namely those concerning the divisibility of composite numbers, primality, and perfect numbers. The chapter then explores Leibniz’s development of binary, his little-known work on binary fractions and expansions, his use of binary as a symbol for creation in his philosophical-theology, and his response to the suggestion that there was a correlation between binary numeration and the hexagrams of the ancient Chinese divinatory text, the Yijing. The chapter then focuses on Leibniz’s work on other number systems, in particular his invention and exploration of hexadecimal as well as his work on duodecimal. The chapter concludes by revealing a hitherto unknown practical application of binary that Leibniz devised in the last year of his life. (shrink)

In the early years of the eighteenth century Leibniz had several interactions with John Toland. These included, from 1702 to 1704, discussions of materialism. Those discussions culminated with the consideration of Toland's 1704 Letters to Serena, where Toland argued that matter is necessarily active. In this paper I argue for two main theses about this exchange and its consequences for our wider understanding. The first is that, despite many claims that Toland was at the time of Letters to Serena (...) a Spinozist, we can make better sense of him as a sort of Hobbesian materialist. The second main point concerns reasons for materialism, and in particular a story Locke tells in the Essay about materialists' motives. Toland defends his materialism by arguing that matter is active, and argues that matter is active by using a conceivability argument. But this is not the crude conceivability argument that Locke suggests motivates materialists. This (together with reflecting on some of Hobbes's arguments) suggests that we might well tell a Lockean story about reasons for early modern materialism, but not Locke's story. (shrink)

Leibniz has been accused of being ambivalent about the nature of sensible qualities such as color, heat, and sound. According to the critics, he unwittingly vacillates between the view that these qualities are really just complex mechanical qualities of bodies and the competing view that they are something like the perceptions or experiences that confusedly represent these mechanical qualities. Against this, I argue that the evidence for ascribing the first approach to Leibniz is rather strong, whereas the evidence (...) for imputing the second approach to him is rather weak. The first, "mechanistic" approach should therefore be regarded as his considered view. (shrink)

The reconstruction of Leibniz’s metaphysics that Deleuze undertakes in The Fold provides a systematic account of the structure of Leibniz’s metaphysics in terms of its mathematical foundations. However, in doing so, Deleuze draws not only upon the mathematics developed by Leibniz—including the law of continuity as reflected in the calculus of infinite series and the infinitesimal calculus—but also upon developments in mathematics made by a number of Leibniz’s contemporaries—including Newton’s method of fluxions. He also draws upon (...) a number of subsequent developments in mathematics, the rudiments of which can be more or less located in Leibniz’s own work—including the theory of functions and singularities, the Weierstrassian theory of analytic continuity, and Poincaré’s theory of automorphic functions. Deleuze then retrospectively maps these developments back onto the structure of Leibniz’s metaphysics. While the Weierstrassian theory of analytic continuity serves to clarify Leibniz’s work, Poincaré’s theory of automorphic functions offers a solution to overcome and extend the limits that Deleuze identifies in Leibniz’s metaphysics. Deleuze brings this elaborate conjunction of material together in order to set up a mathematical idealization of the system that he considers to be implicit in Leibniz’s work. The result is a thoroughly mathematical explication of the structure of Leibniz’s metaphysics. This essay is an exposition of the very mathematical underpinnings of this Deleuzian account of the structure of Leibniz’s metaphysics, which, I maintain, subtends the entire text of The Fold. (shrink)

In 1682, Leibniz published an essay containing his solution to the classic problem of squaring the circle: the alternating converg-ing series that now bears his name. Yet his attempts to disseminate his quadrature results began seven years earlier and included four distinct approaches: the conventional (journal article), the grand (treatise), the impostrous (pseudepigraphia), and the extravagant (medals). This paper examines Leibniz’s various attempts to disseminate his series formula. By examining oft-ignored writings, as well as unpublished manuscripts, this paper (...) answers the question of how one of the greatest mathematicians sought to introduce his first great geometrical discovery to the world. (shrink)

Leibniz claims that Berkeley “wrongly or at least pointlessly rejects abstract ideas”. What he fails to realize, however, is that some of his own core views commit him to essentially the same stance. His belief that this is the best (and thus most harmonious) possible world, which itself stems from his Principle of Sufficient Reason, leads him to infer that mind and body must perfectly represent or ‘express’ one another. In the case of abstract thoughts he admits that this (...) can happen only in virtue of thinking of some image that, being essentially a mental copy of a brain state, expresses (and is expressed by) that state. But here he faces a problem. In order for a thought to be genuinely abstract, its representational content must differ from that of any mental image, since the latter can represent only particular things. In that case, however, an exact correspondence between the accompanying mental image and the brain state would not suffice to establish a perfect harmony between mind and body. Even on Leibniz’s own principles, then, it appears that Berkeley was right to dismiss abstract ideas. (shrink)

In his essay against Eberhard, Kant denies that there are innate concepts. Several scholars take Kant’s statement at face value. They claim that Kant did not endorse concept innatism, that the categories are not innate concepts, and that Kant’s views on innateness are significantly different from Leibniz’s. This paper takes issue with those claims. It argues that Kant’s views on the origin of the intellectual concepts are remarkably similar to Leibniz’s. Given two widespread notions of innateness, the dispositional (...) notion and the input/output notion, intellectual concepts are innate for Kant no less than for Leibniz. (shrink)

A fresh translation and in-depth commentary of Leibniz's seminal text, the Monadology. -/- Written in 1714, the Monadology is widely considered to be the classic statement of Leibniz's mature philosophy. In the space of 90 numbered paragraphs, totalling little more than 6000 words, Leibniz outlines - and argues for - the core features of his philosophical system. Although rightly regarded as a masterpiece, it is also a very condensed work that generations of students have struggled to understand. (...) -/- Lloyd Strickland presents a new translation of the Monadology, alongside key parts of the Theodicy, and an in-depth, section-by-section commentary that explains in detail not just what Leibniz is saying in the text but also why he says it. The sharp focus on the various arguments and other justifications Leibniz puts forward makes possible a deeper and more sympathetic understanding of his doctrines. (shrink)

The first collection of Leibniz's key writings on the binary system, newly translated, with many previously unpublished in any language. -/- The polymath Gottfried Wilhelm Leibniz (1646–1716) is known for his independent invention of the calculus in 1675. Another major—although less studied—mathematical contribution by Leibniz is his invention of binary arithmetic, the representational basis for today's digital computing. This book offers the first collection of Leibniz's most important writings on the binary system, all newly translated by (...) the authors with many previously unpublished in any language. Taken together, these thirty-two texts tell the story of binary as Leibniz conceived it, from his first youthful writings on the subject to the mature development and publication of the binary system. -/- As befits a scholarly edition, Strickland and Lewis have not only returned to Leibniz's original manuscripts in preparing their translations, but also provided full critical apparatus. In addition to extensive annotations, each text is accompanied by a detailed introductory “headnote” that explains the context and content. Additional mathematical commentaries offer readers deep dives into Leibniz's mathematical thinking. The texts are prefaced by a lengthy and detailed introductory essay, in which Strickland and Lewis trace Leibniz's development of binary, place it in its historical context, and chart its posthumous influence, most notably on shaping our own computer age. (shrink)

Leibniz's mill argument in 'Monadology' 17 is a well-known but puzzling argument against materialism about the mind. I approach the mill argument by considering other places where Leibniz gave similar arguments, using the same example of the machinery of a mill and reaching the same anti-materialist conclusion. In a 1702 letter to Bayle, Leibniz gave a mill argument that moves from his definition of perception (as the expression of a multitude by a simple) to the anti-materialist conclusion. (...) Soon afterwards, in the Preface to the New Essays, Leibniz gave a different mill argument. That argument depends upon there being no arbitrary and inexplicable connections in nature, because God would not create such things. Later, in the 'Monadology', Leibniz again used the mill example in arguing against materialism. That passage too, I argue, uses an argument from inexplicability rather than from Leibniz's definition of perception. (shrink)

At the end of 1671 and start of 1672, while in the service of the Archbishop and Elector of Mainz, Leibniz composed his Egypt Plan, which sought to persuade Louis XIV to invade Egypt. Scholars have generally supposed that Leibniz’s rationale for devising the plan was to divert Louis from his intended war with Holland. Little attention has been paid to the religious benefits that Leibniz identified in the plan, and those who do acknowledge them are often (...) quick to downplay them. This tendency to downplay or even dismiss the religious benefits Leibniz claimed of the Egypt Plan is undermotivated and stems from a very superficial reading of the documents that together comprise it. In this paper I argue that we should take seriously Leibniz’s claim that a French invasion of Egypt would bring religious benefits, and that he saw them as important and intrinsically desirable inasmuch as he came to believe that the execution of the plan would lead to the flowering of co-operation and brotherhood among Christians in a show of inter-denominational koinonia, that is, fellowship with other Christians in the participation of shared goals. (shrink)

Not unlike many contemporary philosophers, Leibniz admitted the existence of temporary truths, true propositions that have not always been or will not always be true. In contrast with contemporary philosophers, though, Leibniz conceived of truth in terms of analytic containment: on his view, the truth of a predicative sentence consists in the analytic containment of the concept expressed by the predicate in the concept expressed by the subject. Given that analytic relations among concepts are eternal and unchanging, the (...) problem arises of explaining how Leibniz reconciled one commitment with the other: how can truth be temporary, if concept-containment is not? This paper presents a new approach to this problem, based on the idea that a concept can be consistent at one time and inconsistent at another. It is argued that, given a proper understanding of what it is for a concept to be consistent, this idea is not as problematic as it may seem at first, and is in fact implied by Leibniz’s general views about propositions, in conjunction with the thesis that some propositions are only temporarily true. (shrink)

In Leibniz’s New Essays stands out, within many important topics, his doctrine of innate ideas, which supposes the division between sense knowledge and innate knowledge and implies the distinction between truths of reason and truths of fact. That doctrine is particularly relevant for Leibniz’s philosophy, but implicitly entails the epistemological difference between belief, on one hand, and certainty, on the other. In this paper I outline, according to my interpretation, how Leibniz explains that humans can have certainty (...) about innate ideas. This topic is important because if Leibniz demonstrates the possibility of having certainty of those ideas, then, it is feasible to believe in its existence. However, if his explanation is unsatisfactory his metaphysical doctrine would be seriously weakened and, at the same time, both skepticism and Locke’s empiricist doctrine would be reinforced. (shrink)

In this paper, I analyze a previously unpublished Leibniz text from the early 1700s. I give it the title “On Unities and Transmigration” since it contains an outline of his doctrine of unities and an examination of the doctrine of transmigration. The text is valuable because in it Leibniz considers three very specific versions of transmigration that he does not address elsewhere in his writings; these are (1) where a soul is released by the destruction of its body (...) and is then free to pass into another body, (2) where souls are exchanged without any destruction of bodies, and (3) where human souls (minds) are exchanged, again without any destruction of bodies. I show that when tackling these three versions of transmigration in “On Unities and Transmigration,” Leibniz develops a series of objections that are not found anywhere else in his published writings, despite his lifelong opposition to the doctrine of transmigration. This paper is completed by two appendices, the first of which presents the previously unpublished “On Unities and Transmigration” text in full, in the original French (with all deletions indicated), while the second presents its English translation. (shrink)

Leibniz’s mechanistic reduction of colors and other sensible qualities commits him to two theses about our knowledge of those qualities: first, that we can acquire ideas of sensible qualities apart from any direct acquaintance with the qualities themselves; second, that we can acquire distinct (i.e., non-confused) ideas of such qualities through the development of physical-theoretical accounts. According to some commentators, however, Leibniz frequently denies both claims. His views on the subject are muddled and incoherent, they say, both because (...) he is ambivalent about the nature of sensible qualities, and because he gets confused about confusion, losing sight of his own distinction between the confusion proper to perceptions and that proper to ideas. In opposition to this, I argue that the critics have misunderstood Leibniz’s views, which are both consistent over time and coherent. The key to understanding his position is to appreciate what he characterizes as a kind of redundancy in our ideas of sensible qualities, a crucial feature of his view overlooked by the critics. (shrink)

Drawing on remarks scattered through his writings, I argue that Leibniz has a highly distinctive and interesting theory of color. The central feature of the theory is the way in which it combines a nuanced subjectivism about color with a reductive approach of a sort usually associated with objectivist theories of color. After reconstructing Leibniz's theory and calling attention to some of its most notable attractions, I turn to the apparent incompatibility of its subjective and reductive components. I (...) argue that this apparent tension vanishes in light of his rejection of a widely accepted doctrine concerning the nature of bodies and their geometrical qualities. (shrink)

In the 20th century, Leibniz studies flourished in Italy, as attested by the large number of scholarly articles and translations of his main works. Articles on Leibniz’s philosophy were published in the Archivio di Filosofia, which has long been the journal of the Italian Philosophical Society. This paper examines articles on Leibniz published in Italy, and notably in the Archivio di Filosofia. It is divided into three parts. The first one examines Italian research on Leibniz from (...) 1900 to 1930. The second one takes into account articles on Leibniz published in Archivio di Filosofia from 1930 to 1945. The last part is dedicated to Leibnizian studies published in the same journal after 1945. (shrink)

Leibniz thinks that every created substance is causally active, and yet causally independent of every other: none can cause changes in any but itself. This is not controversial. But Leibniz also thinks that every created substance is existentially independent of every other: it is metaphysically possible for any to exist with or without any other. This is controversial. I argue that, given a mainstream reading of Leibniz’s essentialism, if one accepts the former, uncontroversial interpretation concerning causal independence, (...) then one ought also to accept the latter, controversial one concerning existential independence. This is a new way to defend the ‘existential independence’ interpretation. Moreover, this defense provides a new approach for defending the broadly ‘non-logical’ interpretive camp in the longstanding debate over Leibniz’s views on incompossibility, against perhaps the strongest objection leveled by advocates of the opposing broadly ‘logical’ interpretation. (shrink)

Leibniz accepts causal independence, the claim that no created substance can causally interact with any other. And Leibniz needs causal independence to be true, since his well-known pre-established harmony is premised upon it. So, what is Leibniz’s argument for causal independence? Sometimes he claims that causal interaction between substances is superfluous. Sometimes he claims that it would require the transfer of accidents, and that this is impossible. But when Leibniz finds himself under sustained pressure to defend (...) causal independence, those are not the reasons that he marshals in its defense. Instead, deep into his long correspondence with Burchard de Volder, he gives a different sort of argument, one that has gone nearly unnoticed by commentators and has not yet been properly understood. In part, this is because the argument develops slowly over four years of correspondence. It emerges in early 1704, but it is formulated tersely and appears murky unless understood in light of Leibniz and De Volder’s tangled exchanges. There Leibniz argues that, on his distinctive ontology of an infinity of created substances, no two created substances could possibly causally interact, for roughly the same reasons that some Cartesians like De Volder deny interaction between minds and bodies on their substance dualist ontology. In this paper I draw out this lost argument, explain it and the metaphysics on which Leibniz builds it, and untangle Leibniz and De Volder’s exchanges concerning causation from which this argument results. (shrink)

Leibniz claims that God acts in the best possible way, and that this includes creating exactly one world. But worlds are aggregates, and aggregates have a low degree of reality or metaphysical perfection, perhaps none at all. This is Leibniz’s tendency toward acosmism, or the view that there this no such thing as creation-as-a-whole. Many interpreters reconcile Leibniz’s acosmist tendency with the high value of worlds by proposing that God sums the value of each substance created, so (...) that the best world is just the world with the most substances. I call this way of determining the value of a world the Additive Theory of Value (ATV), and argue that it leads to the current and insoluble form of the problem of incompossibility. To avoid the problem, I read “possible worlds” in “God chooses the best of all possible worlds” as referring to God’s ideas of worlds. These ideas, though built up from essences, are themselves unities and so well suited to be the value bearers that Leibniz’s theodicy requires. They have their own value, thanks to their unity, and that unity is not preserved when more essences are added. (shrink)

Leibniz argues that there must be a fundamental level of simple substances because composites borrow their reality from their constituents and not all reality can be borrowed. I contend that the underlying logic of this ‘borrowed reality argument’ has been misunderstood, particularly the rationale for the key premise that not all reality can be borrowed. Contrary to what has been suggested, the rationale turns neither on the alleged viciousness of an unending regress of reality borrowers nor on the Principle (...) of Sufficient Reason, but on the idea that composites are phenomena and thus can be real only insofar as they have a foundation in substances, from which they directly ‘borrow’ their reality. The claim that composites are phenomena rests in turn on Leibniz's conceptualism about relations. So understood, what initially looked like a disappointingly simple argument for simples turns out to be a rather rich and sophisticated one. (shrink)

According to intellectualists, the will is a rational inclination towards apprehended goodness. This conception of the will makes its acts intelligible: they are explained by (i) the nature of the will as a rational inclination, and (ii) the judgement of the intellect that moves the will. From this it follows that it is impossible for an agent to will evil as such or for its own sake. In explaining wrongdoing intellectualists cite cognitive error or the disruptive influences of the passions; (...) these considerations, however, seem involuntary and at least partly exculpatory. The intellectualist needs an account that renders wrongful actions intelligible without undermining their status as responsible. I argue that Leibniz has the theoretical tools to provide at least part of an answer to this problem. In sum, an agent is directly responsible for her wrongdoing if the cognitive error or the disruptive influence of the passions that help explain this wrongdoing do not completely undermine her acting freely; an agent is indirectly responsible for her wrongdoing if she is directly responsible for previous actions which partly resulted in her wrongdoing, even if the presence of cognitive error or disruptive influence of the passions completely undermines her acting freely. (shrink)

Leibniz Reinterpreted tackles head on the central idea in Leibniz's philosophy, namely that we live in the best of all possible worlds. Strickland argues that Leibniz's theory has been consistently misunderstood by previous commentators. In the process Strickland provides both an elucidation and reinterpretation of a number of concepts central to Leibniz's work, such as 'richness', 'simplicity', 'harmony' and 'incompossibility', and shows where previous attempts to explain these concepts have failed. This clear and concise study is (...) tightly focussed and assumes no prior acquaintance with Leibniz or optimism. It thus serves as an ideal entry point into Leibniz's philosophy. (shrink)

Leibniz's World-Apart Doctrine states that every created substance is independent of everything except God. Commentators have connected the independence of substance asserted by World-Apart to a variety of important aspects of Leibniz's modal metaphysics, including his theory of compossibility and his notion of a possible world (including what possible worlds there are). But what sort of independence is at stake in World-Apart? I argue that there is not a single sense of "independence" at stake, but at least three: (...) what I call "causal", "phenomenal", and "ontological" independence. Further, I distinguish two versions of each type of independence: what I call "basic" and "strict" versions. I argue that only basic versions can be legitimately attributed to Leibniz. In light of this result, I conclude, pace previous commentators, that World-Apart has little impact on Leibniz's modal metaphysics. (shrink)

What would Gottfried Wilhelm Leibniz have said about today’s problem of consciousness? Some philosophers claim that Leibniz was one of the first to argue that there is an ‘explanatory gap’ between our knowledge of matter and our knowledge of consciousness, and that he thought this posed a problem for materialism (see for example Churchland 1995: 191-2; Kriegel 2015: 49; Seager 1991; Searle 1983: 267-8). This is supposed to be the point of the famous passage in the Monadology (1714), (...) in which Leibniz argues that perception is ‘inexplicable in terms of mechanical reasons’... (shrink)

Leibniz endorses several tenets regarding explanation: (1) causes provide contrastive explanations of their effects, (2) the past and the future can be read from the present, and (3) primitive force and derivative forces drive and explain changes in monadic states. I argue that, contrary to initial appearances, these tenets do not preclude an intelligible conception of contingency in Leibniz’s system. In brief, an agent is free to the extent that she determines herself to do that which she deliberately (...) judges to be the best from several considered options that she could have brought about, had she come to the deliberative conclusion that these options were best. I develop a model which illustrates how Leibnizian agents could have come to different deliberative conclusions, and which thus illustrates how Leibnizian agents could have acted differently. (shrink)

Leibniz is not commonly numbered amongst canonical writers on toleration. One obvious reason is that, unlike Locke, he wrote no treatise specifically devoted to that doctrine. Another is the enormous amount of energy which he famously devoted to ecclesiastical reunification. Promoting the reunification of Christian churches is an objective quite different from promoting the toleration of different religious faiths – so different, in fact, that they are sometimes even construed as mutually exclusive. Ecclesiastical reunification aims to find agreement at (...) least on the most important doctrines. Religious toleration involves accepting and respecting disagreement even on the most important doctrines. If one regards these two projects as alternative rather than complementary strategies for dealing with religious diversity, Leibniz might more readily be characterised as an ecumenist rather than a tolerationist. Such appears to be the conclusion, at any rate, implicit in the balance of critical literature on these topics: whereas a steady stream of studies has discussed Leibniz’s project of ecclesiastical reunification, only a meager trickle has been devoted to his views on toleration; and some of these studies go so far as to conclude that Leibniz had no doctrine of toleration at all. This paper will attempt to show, on the contrary, that a robust, many-layered, and unusually inclusive doctrine of toleration can be gleaned from Leibniz’s writings. This doctrine operated at least at three different levels: philosophical, theological, and pragmatic. As this implies, the doctrine of religious toleration, rather than being in collision with Leibniz’s core project of ecclesiastical reunification, was an essential element of that very project: it should be seen, in other words, not as a competing goal, but as a necessary first step toward ecclesiastical reunification. Yet at the same time it will also emerge that Leibniz’s doctrine of toleration was no mere function of this intra-Christian project of reunification: rather it was a still more fundamental principle which extended beyond the ecumenical project as well. It had the resources for accepting and respecting irreducible religious diversity and disagreement on points of importance not only between Christian communities, but also between Christians and non-Christians, including, in principle, even the atheists. These points will emerge from a discussion of statements on the philosophical, theological, and pragmatic justifications of religious toleration scattered throughout Leibniz’s sprawling corpus of writings. (shrink)

Leibniz frequently uses the notion of expression, but it is not easy to see just how he understood that relation. This paper focuses on the particular case of the expression of God, which is prominent in the 'Discourse on Metaphysics'. The treatment of expression there suggests several questions. Which substances did Leibniz believe expressed God? Why did Leibniz believe those substances expressed God? And did he believe that all substances expressed God in the same way and for (...) the same reasons? In answering those questions the paper distinguishes two views about expression in the 'Discourse', considers Leibniz's reasons for holding that substances express their causes, and argues that Leibniz's views about emanative causation are important for understanding the unity of his apparently distinct views here. The paper concludes by looking briefly at how the 'Discourse' fits into the evolution of Leibniz's views on this issue over time. (shrink)

Leibniz has long faced a challenge about the coherence of the distinction between necessary and contingent truths in his philosophy. In this paper, I propose and examine a new way to save genuine contingency within a Leibnizian framework. I conclude that it succeeds in formally solving the problem, but at unbearable cost. I present Leibniz’s challenge by considering God’s choice of the best possible world (Sect. 2). God necessarily exists and necessarily chooses to actualise the best possible world. (...) The actual world therefore could not be different, for if it were different it would be a distinct and inferior world and hence would not be created. In Sect. 3 I defend Leibniz from this challenge. I argue that while it is necessary for God to choose to create the best possible world, it is not necessary for any world to be the best possible. This is because the criterion for judging perfection can itself be contingent. Different criteria will judge different worlds as the best. Thus it is necessary for God to create the best, but not necessary which is the best. Distinguishing between possible worlds in Leibniz’s sense and in the modern sense allows a fuller exposition of this position. There are worries that can arise with the claim that the criterion of perfection is contingent. I consider two of the most pressing (Sect. 4). The first argues that the criterion is in God’s understanding and hence is necessary; the second alleges that a contingent criterion of perfection violates Leibniz’s cherished Principle of Sufficient Reason. These worries are well-grounded, and examining them reveals a deep incompatibility between this solution and Leibniz’s metaphysical views. I conclude that there is a real solution available, but that it is unacceptable to Leibniz or a Leibnizian. The search for a genuine solution that is genuinely Leibnizian goes on. (shrink)

Section 17 of Leibniz’s Monadology contains a famous argument in which considerations of what it would be like to enter a machine that was as large as a mill are offered as reasons to reject materialism about the mental. In this paper, I provide a critical discussion of Leibniz’s mill argument, but, unlike most treatments, my discussion will focus on texts other than the Monadology in which considerations of the mill also appear. I provide a survey of three (...) previous interpretations of the argument and a partial defence of one of them, namely the one that Marc Bobro and I offered in Stepping Back Insider Leibniz's Mill (The Monist, 1998). However, I also argue that a fourth interpretation is necessary to account for the appearances of Leibniz’s mill in at least some of his writings. (shrink)

This essay comments on the complexity of the task of accommodating Leibniz’s account of relational motion with his dynamics, as evident in Anja Jauernig’s (2008) Leibniz Review article, and suggests some possible strategies for overcoming these obstacles.

Our computational metaphysics group describes its use of automated reasoning tools to study Leibniz’s theory of concepts. We start with a reconstruction of Leibniz’s theory within the theory of abstract objects (henceforth ‘object theory’). Leibniz’s theory of concepts, under this reconstruction, has a non-modal algebra of concepts, a concept-containment theory of truth, and a modal metaphysics of complete individual concepts. We show how the object-theoretic reconstruction of these components of Leibniz’s theory can be represented for investigation (...) by means of automated theorem provers and finite model builders. The fundamental theorem of Leibniz’s theory is derived using these tools. (shrink)

I consider Leibniz's thoughts about Hobbes's materialism, focusing on his less-discussed later thoughts about the topic. Leibniz understood Hobbes to have argued for his materialism from his imagistic theory of ideas. Leibniz offered several criticisms of this argument and the resulting materialism itself. Several of these criticisms occur in texts in which Leibniz was engaging with the generation of British philosophers after Hobbes. Of particular interest is Leibniz's correspondence with Damaris Masham. Leibniz may have (...) been trying to communicate with Locke, but ended up discussing Masham's version of the argument for materialism that Leibniz attributed to Hobbes. (shrink)

I argue that Leibniz consistently subscribes to the view that phenomena (thus bodies) have their being in perceiving substances. I then argue that this mentalistic conception of phenomenon coheres with three of his doctrines of body: (1) that bodies presuppose the unities or simple substances on which they are founded; (2) that bodies are aggregates of those substances; and (3) that bodies derive or borrow their reality from their simple constituents.

The task of this paper is to give a new, catholic interpretation of Leibniz’s concept of characteristica universalis. In § 2 we shall see that in different periods of his development, Leibniz defined this concept differently. He introduced it as “philosophical characteristic” in 1675, elaborated it further as characteristica universalis in 1679, and worked on it at least until 1690. Secondly, we shall see (in § 3) that in the last 130 years or so, different philosophers have advanced (...) projects similar to that of Leibniz, not always referring to him, at that. These very projects, we claim, threw some light on what Leibniz idea of characteristica universalis could be; or, in more positive sense, on how could it be reconstructed in a more workable way. Unfortunately, they failed to answer the question what exactly Leibniz’s philosophy was. Finally, despite the fact that Leibniz’s concept of characteristica universalis impressed generations of philosophers who tried to make sense of it, the result is that in the more than 300 years after it was introduced, it was never used in the scale its author dreamed of. This fact sets out the next objective which we are going to pursue in this paper: we shall try to find out (in §§ 4 and 5) how this concept can be interpreted in more practical form. (shrink)

One of the more exotic and mysterious features of Leibniz’s later philosophical writings is the harmony between the kingdom of nature and the kingdom of grace. In this paper I show that this harmony is not a single doctrine, but rather a compilation of two doctrines, namely (1) that the order of nature makes possible the rewards and punishments of rational souls, and (2) that the rewards and punishments of rational souls are administered naturally. I argue that the harmony (...) is best considered as Leibniz’s distinctive collation, development, and rebranding of these doctrines, which were not themselves unique to Leibniz, nor uncommon in the seventeenth century. There follows a detailed examination of various concrete examples of the harmony in operation, from which I show that it is essentially the culmination of Leibniz’s lifelong thinking about divine justice. (shrink)

I argue that an individual has aspects numerically identical with it and each other that nonetheless qualitatively differ from it and each other. This discernibility of identicals does not violate Leibniz's Law, however, which concerns only individuals and is silent about their aspects. They are not in its domain of quantification. To argue that there are aspects I will appeal to the internal conflicts of conscious beings. I do not mean to imply that aspects are confined to such cases, (...) but the best way to start is to recognize them experientially. We can feel the conflicts within ourselves. In doing so we can feel some of our aspects. I will try to enhance our understanding of the concept of aspect by listing and formalizing some principles for its use. After that I will argue that all sorts of individual things have aspects, not just people who are conflicted. (shrink)

Leibniz’s views on modality are among the most discussed by his interpreters. Although most of the discussion has focused on Leibniz’s analyses of modality, this essay explores Leibniz’s grounding of modality. Leibniz holds that possibilities and possibilia are grounded in the intellect of God. Although other early moderns agreed that modal truths are in some way dependent on God, there were sharp disagreements surrounding two distinct questions: (1) On what in God do modal truths and modal (...) truth-makers depend? (2) What is the manner(s) of dependence by which modal truths and modal truth-makers depend on God? Very roughly, Leibniz’s own answers are: (1) God’s intellect and (2) a form of ontological dependence. The essay first distinguishes Leibniz’s account from two nearby (and often misunderstood) alternatives found in Descartes and Spinoza. It then examines Leibniz’s theory in detail, showing how, on his account, God’s ideas provide both truth-makers for possibilities and necessities and an ontological foothold for those truth-makers, thereby explaining modal truths. Along the way, it suggests several refinements and possible amendments to Leibniz’s grounding thesis. It then defends Leibniz against a pair of recent objections by Robert Merrihew Adams and Andrew Chignell that invoke the early work of Kant. I conclude that whereas Leibniz’s alternative avoids collapsing into yet another form of Spinozism, the alternatives proposed by Adams, Chignell, and the early Kant do not. (shrink)

Leibniz' first problem with contingency stems from his doctrine of divine creation (not his later doctrine of truth) and is solved via his concepts of necessity per se, etc. (not via his later concept of infinite analysis). I scrutinize some of the earliest texts in which the first problem and its solution occur. I compare his "per se modal concepts" with his concept of analysis and with the traditional concept of metaphysical necessity. I then identify and remove the main (...) obstacle to Leibniz' employment of these concepts by reflecting on his concept of a world and comparing and contrasting it with contemporary conceptions. Finally I sketch the place that this early problem and its solution had in the context of his mature philosophy. A disagreement between Sleigh and Adams which hinges on the assumption that there is just one problem with competing solutions is seen to dissolve in this light. (shrink)

This paper explores the development of Leibniz’s metaphysics of the Incarnation in the context of his philosophy. In particular it asks to what extent Leibniz’s repeated endorsement of the traditional analogy between the union in humankind of soul (mind) and body, and the union in Christ of divine and human natures, could be accommodated by his more general metaphysical doctrines. Such an investigation highlights some of the deepest commitments in Leibniz’s theory of substance as well as detect (...) in it some unresolved tensions. The paper comes to the conclusion that puzzling points of Leibniz’s metaphysics of the Incarnation, rather than being problems specific to his theology, uncover tensions in his theory of substance as such – tensions converging on the vexed question of whether there can or cannot be genuine corporeal substances in Leibniz’s mature philosophy. (shrink)

Despite holding that all concepts are strictly speaking innate, Leibniz attempts to accommodate the common belief that at least some concepts are adventitious by appealing to his theory of ideal action. The essential idea is that an innate concept can be considered adventitious, in a sense, just in case its ideal cause is to be found outside the mind of the one who possesses the concept. I explore this attempt at accommodation and argue that it fails. [See external link (...) for English draft.]. (shrink)

The ancient doctrine of the eternal return of the same embodies a thoroughgoing rejection of the hope that the future world will be better than the present. For this reason, it might seem surprising that Leibniz constructs an argument for a version of the doctrine. He concludes in one text that in the far distant future he himself ‘would be living in a city called Hannover located on the Leine river, occupied with the history of Brunswick, and writing letters (...) to the same friends with the same meaning.’ However, his argument concludes not that the future will be absolutely identical to the present, but rather that any finite description of the present and future worlds would be identical. In this way, the argument leaves room for the promise of a different and better future—even if it is one that could not be recognized by us as such. (shrink)

Leibniz and Kant were heirs of a biblical theistic tradition which viewed miraculous activity in the world as both possible and actual. But both were also deep explanatory rationalists about the natural world: more committed than your average philosophical theologian to its thoroughgoing intelligibility. These dual sympathies—supernaturalist religion and empirical rationalism—generate a powerful tension across both philosophers’ systems, one that is most palpable in their accounts of empirical miracles—that is, events in nature that violate one or more of the (...) natural laws. The primary goal of this chapter is to exhibit their respective efforts to resolve this tension, and to show how Kant’s noumenal ignorance doctrine allows him to set aside some key difficulties that Leibniz’s model leaves unresolved. The chapter concludes with the unorthodox suggestion that both systems leave conceptual space for the idea that finite free beings, rather than just God, can produce empirical miracles. (shrink)

Leibniz claims that for every possible substance S there is an individual concept that includes predicates describing everything that will ever happen to S, if S existed. Many commentators have thought that this leads Leibniz to think that all properties are had essentially, and thus that it is not metaphysically possible for substances to be otherwise than the way their individual concept has them as being. I argue against this common way of reading Leibniz’s views on the (...) metaphysics of modality. I develop a model in which individual concepts are innocent; that is, individual concepts are divine ideas that permit God to know everything that will ever happen to all possible substances, if created, but these individual concepts neither require that all properties are had essentially nor require that it is metaphysically necessary for substances to be the way their individual concepts have them as being. (shrink)

In this paper, we consider what is commonly referred to as Leibniz’s argument for primitive concepts. After presenting and criticizing (in sections 1 and 2) one recent rather straightforward way of interpreting this argument, by Paul Lodge and Stephen Puryear, which takes the argument to be merely about the structure of concepts, we offer an alternative way of looking at the argument. We think it is best seen as being fundamentally about the relation between thought and reality. In order (...) to prepare the ground for our reconstruction (which we present in section 5), we have to introduce his view of ideas or concepts (section 3), as well as some metaphysical principles concerning reality-dependence (section 4). (shrink)

On 1 November 1755, the city of Lisbon in Portugal was virtually destroyed by the largest documented seismic event ever to hit Europe. It is often claimed that the catastrophe severely damaged the plausibility of Leibniz’s optimism, and even the wider project of theodicy. Leibniz died several decades before the Lisbon earthquake struck, and so was unable to address it and the challenges thrown up by it, which would have included an account of how the event was consistent (...) with God’s providence. Contemporary scholars are of the view that Leibniz explained natural disasters like earthquakes as nothing more than the unfortunate consequences of the normal workings of simple laws of nature, and that God permits such disasters to happen because it would be unworthy of him to overrule the laws he has established. There certainly is this line of thinking in Leibniz’s writings, but it is far from being the whole story, as we shall see. The aim of this paper is to determine what Leibniz’s response to the Lisbon earthquake would have been, had he lived to know about the event. (shrink)