According to the most prominent principle of early modern rationalists, the Principle of Sufficient Reason [PSR], there are no brute facts, hence, there are no facts without any explanation. Contrary to the PSR, some philosophers have argued that divine ideas are brute facts within Leibniz’s metaphysics. In this paper, I argue against brute-fact-theories of divine ideas, especially represented by Samuel Newlands in Leibniz and the Ground of Possibility, and elaborate an alternative Leibnizian theory of divine ideas.

ABSTRACTHow did the traditional doctrine of parts and wholes evolve into contemporary formal mereology? This paper argues that a crucial missing link may lie in the early modern and especially Wolf...

This paper examines the Leibnizian background to Kant's critique of the ontological argument. I present Kant's claim that existence is not a real predicate, already formulated in his pre-critical essay of 1673, as a generalization of Leibniz's reasoning regarding the existence of created things. The first section studies Leibniz's equivocations on the notion of existence and shows that he employs two distinct notions of existence ? one for God and another for created substances. The second section examines Kant's position in (...) his early paper of 1763. My claim is that Kant's view of existence in 1763, namely that it is not a predicate, is strongly related to the logical notion of possibility, formulated by Leibniz and accepted by Kant. (shrink)

In a recent paper Johan van Benthem reviews earlier work done by himself and colleagues on ‘natural logic’. His paper makes a number of challenging comments on the relationships between traditional logic, modern logic and natural logic. I respond to his challenge, by drawing what I think are the most significant lines dividing traditional logic from modern. The leading difference is in the way logic is expected to be used for checking arguments. For traditionals the checking is local, i.e. separately (...) for each inference step. Between inference steps, several kinds of paraphrasing are allowed. Today we formalise globally: we choose a symbolisation that works for the entire argument, and thus we eliminate intuitive steps and changes of viewpoint during the argument. Frege and Peano recast the logical rules so as to make this possible. I comment also on the traditional assumption that logical processing takes place at the top syntactic level, and I question Johan’s view that natural logic is ‘natural’. (shrink)

I aim to offer an innovative interpretation of Leibniz’s philosophy, first by examining how the various views that make up his ontology of individual substance involve a persistent rejection of atomism in natural philosophy and secondly, by exploring the significance of this rejection in the larger context of Seventeenth-century physics. My thesis is structured as a developmental story, each chapter analyzing the discontinuities or changes Leibniz makes to his views on individuation and atomism from his early to late years. The (...) goal is to illuminate underrepresented views on individuals and atoms throughout Leibniz’s works and thus bring a clearer understanding of his philosophy. I, therefore, argue that the New System of Nature, published towards the end of Leibniz’s middle period (1695), marks an important landmark in his philosophical evolution, a radical terminological and ontological shift in his metaphysics of substance. Once Leibniz elaborates the concept of “simple substance,” the future synonym of “monad,” the problem of individuation of his early and middle years (1663-1686) becomes secondary. The focus changes from what makes substances “individual” to what makes them “simple” and truly “one,” i.e., “metaphysical” atoms. I prove that this shift was marked by a two-tiered critical confrontation: a first, direct confrontation, 1) with Descartes’ physics, through the critique of the notion of extended matter and of Descartes’ principle of individuation through shared motion and, a second confrontation, 2) with different strands of Seventeenth-century atomism, including Cartesian Gérauld de Cordemoy’s quasi-“metaphysical” atomism and its attempt at improving Descartes’ individuating principle. I claim that this double confrontation ultimately led Leibniz to formulate a more fundamental ontology, in terms of the “metaphysical atomism” of his Monadology (1714). My analysis complicates a persistent scholarly assumption in recent Leibniz studies, claiming that, throughout his entire career, Leibniz continued to hold the same fundamental positions on substance, individuation and, implicitly, atoms. Against this type of general continuity thesis, I show that: 1) far from being a constant concern, Leibniz’s interest in what makes substances individual fades towards the end of his life (New Essays 1703, correspondence with Samuel Clarke, 1714); 2) I trace the changing fate of some of Leibniz’s early and middle period views on substance and the individual (the principle of the identity of indiscernibles, space-time as individuating properties) in his late works; and 3) I prove the claim that Leibniz really embraced atomism, either for a short time or all throughout his philosophy is problematic. While he does refer to some sort of atoms during his Paris period (1672-1676), this is insufficient proof of a commitment to atomism. Instead, the episode has to be understood in the broader framework of a bundle of interrelated issues, such as the problem of the cohesion of bodies and the problem of minds or mind-like principles individuating those bodies. Thus, as I show through an analysis of Leibniz’s arguments against atomism in the correspondences with his scientific contemporaries (Christiaan Huyghens 1692-1695, Nicholas Hartsoeker 1706-1714), rejecting physical atomism remains a fundamental and surprisingly constant point of his philosophy. (shrink)

This paper consists in a study of Leibniz’s argument for the infinite plurality of substances, versions of which recur throughout his mature corpus. It goes roughly as follows: since every body is actually divided into further bodies, it is therefore not a unity but an infinite aggregate; the reality of an aggregate, however, reduces to the reality of the unities it presupposes; the reality of body, therefore, entails an actual infinity of constituent unities everywhere in it. I argue that this (...) depends on a generalized notion of aggregation, according to which a thing may be an aggregate of its constituents if every one of its actual parts presupposes such constituents, but is not composed from them. One of the premises of this argument is the reality of bodies. If this premise is denied, Leibniz’s argument for the infinitude of substances, and even of their plurality, cannot go through. (shrink)