In this paper I argue that the hoary theological doctrine of divine concurrence poses no deep threat to Leibniz’s views on theodicy and creaturely activity even as those views have been traditionally understood. The first three sections examine respectively Leibniz’s views on creation, conservation and concurrence, with an eye towards showing their sys­tematic compatibility with Leibniz’s theodicy and metaphysics. The fourth section takes up remaining worries arising from the bridging principle that conservation is a continued or continuous creation, and argues that they can be allayed once two readings of the prin­ciple are distinguished. What emerges from the discussion as a whole is, I hope, a clearer picture of Leibniz’s views on the nature of monadic causation, his understanding of the relationship between divine and creaturely activity, and his position with respect to later medieval and early modern debates over secondary causation.

In the Nouveaux Essais, Leibniz famously declared that he once had “begun to lean towards” Spinozist necessitarianism. In this article, I argue that this remark refers to his modal philosophy anterior to 1677. Leibniz’s mature refutation of Spinoza’s necessitarianism relies on the notion that pure possibility has some sort of reality in God’s mind, because only this allows for a strong notion of divine choice. But I believe that Leibniz only developed this ontology of possibility after 1677. Before this date, he inclined towards the view that non existing possibilities are mere logical abstractions that God never actually conceives. In order to show this, I analyze a series of early texts written between 1668 and 1676. Next, I consider a series of texts from 1677-1678, where Leibniz developed his ontology of possibility and put it to use against Spinozist necessitarianism for the first time.

In light of the growing interest in the relation between Leibniz and Spinoza in recent years, I would like to draw attention to earlier discussions of this topic in Germany and France during the 19th century. Stein and Erdmann argued that Spinoza had an impact on Leibniz. According to their critics Guhrauer, Trendelenburg and Gerhardt in Germany, as well as Foucher de Careil in France, Leibniz studied Spinoza only after the main points of his system were already developed. I will show that the well known thesis about the amazing continuity in Leibniz’ thinking is due to this claim of a general chronological impossibility of any impact of Spinoza on Leibniz. This thesis was then canonized in Mahnke’s book about the young Leibniz and has determined the view of Leibniz since the end of the 19th century. It has only in recent years come to be increasingly challenged.

What is Leibniz’s argument for simple substances? I propose that it is an extension of his prior argument for incorporeal forms as principles of unity for individual corporeal substances. The extension involves seeing the hylomorphic analysis of corporeal substances as implying a resolution of matter into forms, and this seems to demand that forms, which are themselves simple, be the only elements of things. The argument for simples thus presupposes the existence of corporeal substances as a key premise. Yet a theory of simple substances as the elements of things threatens to preclude the existence of corporeal substances for Leibniz, and the extension of the argument for forms into an argument for simples is not cogent. If nothing else rides on the simplicity of individual substances, then perhaps instead of being its most fundamental tenet, the doctrine of simples—the monadology—is something that over-extends and destabilizes Leibniz’s metaphysics.

Starting from Leibniz’s complaint that Newton’s views seem to make God the soul of the world, this paper examines Leibniz’s critical stance more generally towards God as the soul of the world and related theses. A preliminary task is determining what the related theses are. There are more of these than might have been thought. Once the relations are established, it becomes clear how pervasive the various guises of the issue of God as the soul of the world are in Leibniz’s thought and how central they are in his debates with contemporaries about the truths of natural religion and even more strictly philosophical issues. Leibniz’s arguments against God as the soul of the world are reconstructed and evaluated, and the difficult question of the exact meaning, or meanings, that Leibniz ascribes to the thesis that God is the soul of the world is taken up. The clearest core of meaning discussed in this paper is most directly relevant to Leibniz’s criticisms of Spinoza and the Stoics, as well as of Descartes. Less clear, but obviously important, are meanings relevant to Leibniz’s debates with the occasionalists and Newtonians.

Contrary to popular belief, I argue that Leibniz is not hopelessly confused about motion: Leibniz is indeed both a relativist and an absolutist about motion, as suggested by the textual evidence, but, appearances to the contrary, this is not a problem; Leibniz’s infamous doctrine of the equivalence of hypotheses is well-supported and well-integrated within Leibniz’s physical theory; Leibniz’s assertion that the simplest hypothesis of several equivalent hypotheses can be held to be true can be explicated in such a way that it makes good sense; the mere Galilean invariance of Leibniz’s conservation law does not compromise Leibniz’s relativism about motion; and Leibniz has a straightforward response to Newton’s challenge that the observable effects of the inertial forces of rotational motions empirically distinguish absolute from relative motions.

In this paper I challenge the common view that early in his career (1679-1695) Leibniz held that space and time are well-founded phenomena, entities on an ontological par with bodies and their properties. I argue that the evidence Leibniz ever held that space and time are well-founded phenomena is extremely weak and that there is a great deal of evidence for thinking that in the 1680s he held a position much like the one scholars rightly attribute to him in his mature period, namely, that space and time are merely orders of existence and as such are purely abstract and occupy an ontological realm distinct from that of well-founded phenomena. In the course of arguing for this interpretation, I offer an account of the nature of Leibnizian phenomena which allows Leibniz to hold the view that space and time are phenomena, while at the same time thinking of them as abstract, ideal orders of existence.

This paper examines the young Kant’s claim that all motion is relative, and argues that it is the core of a metaphysical dynamics of impact inspired by Leibniz and Wolff. I start with some background to Kant’s early dynamics, and show that he rejects Newton’s absolute space as a foundation for it. Then I reconstruct the exact meaning of Kant’s relativity, and the model of impact he wants it to support. I detail (in Section II and III) his polemic engagement with Wolffian predecessors, and how he grounds collisions in a priori dynamics. I conclude that, for the young Kant, the philosophical problematic of Newton’s science takes a back seat to an agenda set by the Leibniz-Wolff tradition of rationalist dynamics. This results matters, because Kant’s views on motion survive well into the 1780s. In addition, his doctrine attests to the richness of early modern views of the relativity of motion.

In this article, I discuss how Leibniz’s first correspondence with Malebranche from early 1676 can shed new light on the notorious “all-things-are-one”-passage (ATOP) found in the Quod ens perfectissimum sit possibile from late 1676—a passage that has been taken as an expression of monism or Spinozism in the young Leibniz. The correspondence with Malebranche provides a deeper understanding of Leibniz’s use of the notions of “real distinction” and “separability” in the ATOP. This forms the background for a discussion of Leibniz’s commitment to the monist position expounded in the ATOP. Thus, on the basis of a close analysis of Leibniz’s use of these key terms in the Malebranche correspondence, I provide two possible, and contrary, interpretations of the ATOP, namely, a “non-commitment account” and a “commitment account.” Finally, I explain why I consider the commitment account to be the more compelling of the two.