The Correspondence with Arnauld

Leibniz’s correspondence with Antoine Arnauld took place in his so-called “middle period”: it began in February 1686 and ended in March 1690, when Leibniz wrote his final letter to Arnauld. The exchange was initiated by Leibniz, who sent Arnauld a short summary of his most recent philosophical composition, the “Discourse on Metaphysics”, and asked Arnauld for his opinion. The ensuing correspondence is an excellent source of information about Leibniz’s views in the middle period: it contains a thorough, clear, and surprisingly systematic presentation of many of his most important philosophical doctrines. This chapter focuses on what we can learn from these letters about Leibniz’s theory of complete concepts, his account of body and substance, his doctrines about causation, and finally his theory that minds have a special status in God’s plan.

“Confessio philosophi”

The “Confessio philosophi” is an early dialogue in which Leibniz engages with what he takes to be the central task of theodicy: to uphold the justice of God. It evinces his commitment to the claim that ours is the best possible world, and offers an account of how such a world could include damnation. Various answers to the question why God is justified in permitting sin are suggested in the dialogue. These are addressed in this chapter, which also highlights a threat to God’s justice raised by the doctrine of eternal damnation which is given surprisingly little attention. The chapter concludes with a discussion of the place of the “Confessio philosophi” in Leibniz’s lifelong theodicy project.

“Discourse on the Natural Theology of the Chinese”

Leibniz wrote the “Discourse on the Natural Theology of the Chinese” during the last year of his life. Previously, he had praised the polity and societal peace of the Chinese empire, deeming it superior to that of Christian Europe. Various thinkers used such a claim to argue that a pagan society could be ethical and politically stable without the belief in God. Leibniz sought to demonstrate that the intellectual and spiritual foundations of ancient Confucianism were indeed monotheistic and that this was the basis of their well-ordered society. He attempted to show that the classical Chinese believed in the tenets of a natural theology (i.e. belief in the existence of a monotheistic God and an incorporeal and hence immortal soul). He even attributed the discovery of binary arithmetic, not to himself, but to the ancient founder of the Yi Jing, thus further legitimating ancient Chinese knowledge (“science”).

The Correspondence with Clarke

The correspondence between Leibniz and Samuel Clarke—mediated by Leibniz’s erstwhile friend and disciple at the electoral court in Hanover, Caroline of Brandenburg-Ansbach, princess of Wales—is arguably the most famous and influential of philosophical correspondences. In this chapter, I begin by tracing the background of the correspondence and the role that Caroline played in its inception and development. I then turn to a discussion of the main themes of the correspondence, paying particular attention to the importance of Caroline’s presence in shaping the themes of the debate: the principle of sufficient reason, the identity of indiscernibles, God’s choice in creating this world, space and time, God’s presence and activity in the world, miracles, and gravity.

The Theodicy

This chapter provides an overview of one of Leibniz’s longest and most important works, the Theodicy. It is argued that the Theodicy is best understood against a careful reading of the Preface, where Leibniz outlines the primary aim of the book, i.e. to provide the means by which natural theology and Leibniz’s conception of God as a being deserving of love may be maintained in the face of objections that stem from considering the nature of freedom and the so-called “problem of evil”. Due to space constraints, the chapter presents the main issues by focusing mainly on their presentation in Part1 rather than on the way in which Leibniz contrasts his views with those of with Pierre Bayle in Parts 2 and 3. It also includes a detailed discussion of the Preliminary Dissertation on the Conformity of Faith with Reason, in which Leibniz spells out his conception of the relationship between these notions.

The Correspondence with De Volder

Leibniz’s correspondence with Burcher de Volder contains some of his most important philosophical writings. Taking place between 1698 and 1706, the correspondence engages a range of issues including the nature of substance, causation, space and time, the proper measure of force in physics, and the relation between physics and metaphysics. It is most famous for containing extensive remarks on Leibniz’s theory of monads, though the extent to which he was committed to this theory throughout the correspondence is a matter of great scholarly controversy. I suggest that one of the keys for interpreting this correspondence is to recognize its pedagogical character. Leibniz did not straightforwardly present his metaphysics to De Volder at the beginning of the correspondence; rather, he gradually revealed his views in an effort to rid De Volder of his philosophical prejudices and enable him to recognize the true metaphysical system.

“Discourse on Metaphysics”

The “Discourse on Metaphysics” is widely considered to be Leibniz’s most important philosophical work from his so-called “middle period”. Written early in 1686, when Leibniz was 39 years old, it consolidates a number of philosophical ideas that he had developed and sketched out in the years beforehand in a host of short private essays, fragments, and letters. This chapter guides the reader through the key themes of the “Discourse”, such as God’s choice of the best, the nature of substance, final causes, and the relationship between soul and body. The essay concludes with a consideration of what prompted Leibniz to write the “Discourse”; I suggest that the “Discourse” is likely to have been conceived as an attempt to reach supporters of Descartes and Malebranche, not only to challenge key tenets of their respective philosophies but also to present a viable alternative.

“De summa rerum”

This chapter is dedicated to a perplexing set of philosophical fragments today known as “De summa rerum”. Written by the young Leibniz in 1675–6, toward the end of his formative years in Paris, they deal with fundamental topics of philosophy including the first principles of philosophy, the nature of mind and perception, the nature and existence of God, the derivation of particular things from God, and modal philosophy. The “De summa rerum” fragments do not represent a unified philosophical attempt. Written at a time when Leibniz’s intellectual mindset had been both upset and profoundly stimulated by his encounter with the Parisian intellectual scene and his discovery of mathematics, they rather read like a set of philosophical test balloons flying in a great many directions. This chapter focuses on one particularly important strand of these reflections, informed by Spinoza and Spinozism via Leibniz’s exchanges with Ehrenfried Walther von Tschirnhaus.

The “Monadology”

Written in 1714, the “Monadology” is widely regarded as a classic statement of much of Leibniz’s mature philosophical system. In just 90 numbered paragraphs, Leibniz outlines—and argues for—the core features of his system, starting with his famous doctrine of monads (simple substances) and ending with the uplifting claim that God is concerned not only for the world as a whole but for the welfare of the virtuous in particular. This chapter begins by considering the circumstances of composition of the “Monadology” and its publication history before offering a detailed analysis of the claims and arguments found therein; I suggest the text is best read as dealing with three distinct realms, the metaphysical (§§1–60), the physical (§§61–82), and lastly the moral (§§83–90). The chapter concludes with a consideration of the fate and influence of this seminal text.

Introduction, including a sketch of Leibniz’s life and philosophical works

The noted historian of the philosophy of late antiquity Pierre Hadot once remarked: I always prefer to study a philosopher by analysing his or her works rather than looking to put together a system by extracting theoretical propositions from his or her works, separated from their context. The works are alive; they are an act, a movement that carries the author and the reader....