Stefano Di Bella

The chapter considers the presence of nominalist motives in the development of Leibniz’s logical and ontological thought. The discussion begins with Leibniz’s Preface to his reedition of the work of the Renaissance nominalist Nizolius, and emphasizes Leibniz’s acceptance of antirealistic assumptions, his balancing of them with Platonic elements, and his rejection of Hobbes’s conventionalist implications. There is also a consideration of the deflationary treatment of abstract terms that Leibniz offers as part of his program of providing ontological clarification by way of semantic analysis. Leibniz applies an analysis of abstract talk stemming from Hobbes, with the aim of availing himself of the resources of certain expressive devices in logical and scientific language, while avoiding realistic commitments. Leibniz’s final profession of a “precautionary nominalism” confirms his preference for ontological economy, but also leaves unresolved some problems in his “austere” account of the ontology of predication and change.

The ancient topic of universals was central to scholastic philosophy, which raised the question of whether universals exist as Platonic forms, as instantiated Aristotelian forms, as concepts abstracted from singular things, or as words that have universal signification. It might be thought that this question lost its importance after the decline of scholasticism in the modern period. However, the fourteen contributions to this volume indicate that the issue of universals retained its vitality in modern philosophy. Modern philosophers in fact were interested in three sets of issues concerning universals: (1) issues concerning the ontological status of universals, (2) issues concerning the psychology of the formation of universal concepts or terms, and (3) issues concerning the value and use of universal concepts or terms in the acquisition of knowledge. Chapters in this volume consider the various forms of “Platonism,” “conceptualism,” and “nominalism” (and distinctive combinations thereof) that emerged from the consideration of such issues in the work of modern philosophers. The volume covers not only the canonical modern figures, namely, Descartes, Spinoza, Leibniz, Locke, Berkeley, Hume, and Kant, but also more neglected figures such as Pierre Gassendi, Pierre-Sylvain Regis, Nicolas Malebranche, Henry More, Ralph Cudworth, and John Norris.

The aim of this paper is to trace in Leibniz’s drafts the sketched outline of a conceptual framework he organized around the key concept of ‘requisite’. We are faced with the project of a semi-formal theory of conditions, whose logical skeleton can have a lot of different interpretations. In particular, it is well suited to capture some crucial relations of ontological dependence. Firstly the area of ‘mediate requisites’ is explored - where causal and temporal relations are dealt with on the basis of a general theory of ‘consequence’.Then the study of ‘immediate requisites’ is taken into account - a true sample of mereological inquiry, where Leibniz strives for a unitary treatment of part-whole relation, conceptual inclusion and inherence. Far from simply conflating these relations one with another and with causality, therefore, Leibniz tried to spell them out, while at the same time understanding them within a single conceptual framework.

Leibniz's treatment of the concept of res should be considered in the context of his semantic-ontological reflections on the relationship of language, thought and reality, profoundly shaped by a nominalistically minded deflationary approach. In this paper I consider (a) the role of res as a kind of super-category and its relationship with ens; then I pass to consider the narrower usage of res to designate a concrete item, in the sense (b) of a subject of inherence as opposed to properties, and (c) of an object as opposed to a concept.

“Baroque” sensitivity - a concept elusive enough - develops in the complex post-Renaissance culture and largely co-exists with the new culture shaped by seventeenth-century scientific revolution. In Leibniz’s experience a totally “modern” exploration of the new world mixes with the adoption of rhetorical tools and spiritual attitudes typical of baroque culture. I present here some samples of this Leibnizian approch, where some central themes of the new science and new philosophy (mechanism, representation, the issue of the sense of reality) are reinterpreted within an original practice of re-enchanting and theatralizing of world.

The 1648 exchange between Descartes and Arnauld focuses on several distinct but intertwined topics concerning Descartes’s philosophy of mind. Descartes’s acknowledgment of thinking as the essence of the mind implied a strong ‘actualist’ view of this essential activity. Arnauld’s objcetions reveal the problematic implications of this ontology of mind, from the role of memory and the temporal nature of our thought to the radical challenge of giving the status of an essence to such a temporal activity.