According to a common reading, Spinoza and Leibniz stand on opposite ends of the modal spectrum. At one extreme lies ‘‘Spinoza the necessitarian,’’ for whom the actual world is the only possible world. At the other lies ‘‘Leibniz the anti-necessitarian,’’ for whom the actual world is but one possible world among an infinite array of other possible worlds; the actual world is privileged for existence only in virtue of a free decree of a benevolent God. In this paper, I challenge (...) both of these readings. Spinoza is no necessitarian and Leibniz is no anti-necessitarian – at least as these characterizations are usually understood. Rather, I contend, Spinoza and Leibniz are both anti-essentialists; they believe that the modality of objects can vary relative to how those objects are conceived. This shared commitment to anti-essentialism allows them to consistently affirm both necessitarianism and its denial, relative to different ways of conceiving the world. Their embrace of this modal theory, I further argue, is grounded in their similar views on metaphysical perfection, ontological plentitude, and the principle of sufficient reason. (shrink)

In the Monadology Leibniz has us imagine a thinking machine the size of a mill in order to show that matter can’t think. The argument is often thought to rely on the unity of consciousness and the notion of simplicity. Leibniz himself did not see matters this way. For him the argument relies on the view that the qualities of a substance must be intimately connected to its nature by being modifications, limitations of its nature. Leibniz thinks perception is not (...) a modification of matter because it is active and matter is passive. At the same time, there are traces in Leibniz of a different argument that relies on the notion of internal action, which may involve the notion of simplicity. Critics have sometimes charged that the Mill Argument is an argument from ignorance, but Leibniz was aware of this problem and made clear that he did not make that mistake. (shrink)

Leibniz claims that nature is actually infinite but rejects infinite number. Are his mathematical commitments out of step with his metaphysical ones? It is widely accepted that Leibniz has a viable response to this problem: there can be infinitely many created substances, but no infinite number of them. But there is a second problem that has not been satisfactorily resolved. It has been suggested that Leibniz’s argument against the world soul relies on his rejection of infinite number, and, as such, (...) Leibniz cannot assert that any body has a soul without also accepting infinite number, since any body has infinitely many parts. Previous attempts to address this concern have misunderstood the character of Leibniz’s rejection of infinite number. I argue that Leibniz draws an important distinction between ‘wholes’– collections of parts that can be thought of as a single thing – and ‘fictional wholes’ – collections of parts that cannot be thought of as a single thing, which allows us to make sense of his rejection of infinite number in a way that does not conflict either with his view that the world is actually infinite or that the bodies of substances have infinitely many parts. (shrink)

The paper examines Kant’s views on divine foreknowledge of contingent truths, in particular truths concerning free actions of creatures. It first considers the shape this traditional philosophical problem takes in the transcendental idealist context. It then situates Kant’s views relative to three competing theories of foreknowledge discussed by Leibniz. These are Molina’s theory of middle knowledge, the Thomist theory of foreknowledge through divine predeterminations, and Leibniz’s own ‘possible worlds’ theory. The paper concludes that no consistent theory of divine foreknowledge emerges (...) in Kant’s philosophy. His discussions alternate between two inadequate and incompatible models. One is a post-volitional model suggested by his conception of the intuitive intellect’s relation to creation. Extended to creaturely free action, it is incompatible with his commitment to the relative autonomy of free action. The other is a version of Leibniz’s possible worlds solution; it cannot underwrite certain foreknowledge of determinate outcomes in a libertarian setting. (shrink)

This paper is a discussion of the treatment of Leibniz's conception of substance in Heidegger's The Metaphysical Foundations of Logic. I explain Heidegger's account, consider its relation to recent interpretations of Leibniz in the Anglophone secondary literature, and reflect on the ways in which Heidegger's methodology may illuminate what it is to read Leibniz and other figures in the history of philosophy.

Leibniz argues that Cartesian extension lacks the unity required to be a substance. A key premise of Leibniz’s argument is that matter is a collection or aggregation. I consider an objection to this premise raised by Leibniz’s correspondent Burchard de Volder and consider a variety of ways that Leibniz might be able to respond to De Volder’s objection. I argue that it is not easy for Leibniz to provide a dialectically relevant response and, further, that the difficulty arises from Leibniz’s (...) commitment to part-whole priority in the case of material wholes, a commitment not shared by De Volder. One major implication is that Leibniz relies on a bottom-up conception of material things, which makes his argument vulnerable to objections stemming from certain types of monist positions. (shrink)

According Leibniz's thesis of universal expression, each substance expresses the whole world, i.e. all other substances, or, as Leibniz frequently states, from any given complete individual notion (which includes, in internal terms, everything truly attributable to a substance) one can "deduce" or "infer" all truths about the whole world. On the other hand, in Leibniz's view each (created) substance is internally individuated, self-sufficient and independent of other (created) substances. What may be called Leibniz's expression problem is, how to reconcile these (...) views with each other, that is, how a substance that expresses the whole world, even in the sense that the whole world can be "inferred" from its complete individual notion, can be self-sufficient and internally individuated. The purpose of this paper is to give an exact account of this tricky problem of universal expression, an account that retains substances' self-sufficiency under the constraint that all truths about the whole world are to be obtained from complete individual notions. It will also be shown how the explication of universal expression to be given accounts for Leibniz's thesis of universal change, i.e. the view that any change in any substance is reflected as a real, internal change in each and every other substance. (shrink)

This chapter discusses Gottfried Wilhelm Leibniz’s philosophical reflections on mind and body. It first considers Leibniz’s distinction between substance and aggregate, referring to the former as a being that must have true unity (what he calls unum per se) and to the latter as simply a collection of other beings. It then describes Leibniz’s extension of the term “substance” to monads and other things such as animals and living beings. It also examines Leibniz’s views about the union of mind and (...) body, whether mind and body interact, and how interaction is related to union. More specifically, it asks whether mind and body together constitute an unum per se and analyzes Leibniz’s account of the per se unity of mind-body composites. In addition, the chapter explores the problem of soul-body union as opposed to mind-body union and concludes by discussing Leibniz’s explanation of soul-body interaction using a system of pre-established harmony. (shrink)

This article is about the exchanges between Leibniz, Arnauld, Bayle and Lamy on the subject of pain. The inability of Leibniz’s system to account for the phenomenon of pain is a recurring objection of Leibniz’s seventeenth-century Cartesian readers to his hypothesis of pre-established harmony: according to them, the spontaneity of the soul and its representative nature cannot account for the affective component of pain. Strikingly enough, this problem has almost never been addressed in Leibniz studies, or only incidentally, through the (...) more general problem of evil. My purpose in this article is to clarify Leibniz’s psychophysical parallelism by opposing his representationist account of pain to the functionalist account endorsed by Arnauld, Bayle, Lamy and Malebranche. (shrink)