Leibniz's well-known thesis that the actual world is just one among many possible worlds relies on the claim that some possibles are incompossible , meaning that they cannot belong to the same world. Notwithstanding its central role in Leibniz's philosophy, commentators have disagreed about how to understand the compossibility relation. We examine several influential interpretations and demonstrate their shortcomings. We then sketch a new reading, the cosmological interpretation, and argue that it accommodates two key conditions that any successful interpretation must (...) satisfy. (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)

The ArgumentThe claim that Jan Swammerdam's empirical research did not support his theory of biological preformation is shown to rest on a notion of evidence narrower than that used by many seventeenth-century natural philosophers. The principles of evidence behind the use of mechanical models are developed. It is then shown that the Cartesian theory of biological reproduction and embryology failed to gain acceptance because it did not meet the evidential requirements of these principles. The problems in this and other mechanistic (...) theories prior to Swammerdam are found to arise from certain difficulties and tensions in the mechanical conception of nature, which Swammerdam's theory is able to resolve. The relation between Swammerdam's empirical research and his theory is examined and shown to satisfy the required notion of evidence.Leibniz' puzzling appeals to Swammerdam's research in support of his metaphysical doctrine of the spontaneous development of individual substances are then examined and shown to fall within the parameters of the notion of evidence. (shrink)

This anthology is about the signal change in Leibniz’s metaphysics with his explicit adoption of substantial forms in 1678-79. This change can either be seen as a moment of discontinuity with his metaphysics of maturity or as a moment of continuity, such as a passage to the metaphysics from his last years. Between the end of his sejour at Paris and the first part of the Hanover period, Leibniz reformed his dynamics and began to use the theory of corporeal substance. (...) This book explores a very important part of the philosophical work of the young Leibniz. Expertise from around the globe is collated here, including Daniel Garber’s work based on the recent publication of Leibniz's correspondence from the late 1690s, examining how the theory of monads developed during these crucial years. Richard Arthur argues that the introduction of substantial forms, reinterpreted as enduring primitive forces of action in each corporeal substance, allows Leibniz to found the reality of the phenomena of motion in force and thus avoid reducing motion to a mere appearance. Amongst other themes covered in this book, Pauline Phemister’s paper investigates Leibniz’s views on animals and plants, highlighting changes, modifications and elaborations over time of Leibniz’s views and supporting arguments and paying particular attention to his claim that the future is already contained in the seeds of living things. The editor, Adrian Nita, contributes a paper on the continuity or discontinuity of Leibniz’s work on the question of the unity and identity of substance from the perspective of the relation with soul and mind. (shrink)

I have three main objectives in this essay. First, in chapter 2, I shall put forward and justify what I call worldlessness, by which I mean the following: All truths (as well as falsehoods) are wholly independent of any circumstances, not only time and place but also possible worlds. It follows from this view that whatever is actually true must be taken as true with respect to every possible world, which means that all truths are (in a sense) necessary. However, (...) the account I shall propound is different from what is known in the trade as necessitarianism, i.e. the view that there is only one possible world, viz. the actual one, for the doctrine of the worldlessness of truth values, despite its commitment to the necessity of truths and falsehoods, is quite compatible with the idea of there being other possible worlds. Another important issue in chapter 2, explored in particular in section 2.12, is the claim that there is no real change in the world. Secondly, in chapter 3 I consider the eminent traditional argument for determinism, deriving from Aristotle, namely, logical determinism, i.e. determinism justified by an appeal to the logical principle of bivalence (that all proper statements, including those concerning the future, are either true or false). In this connection I try to show that, (i), the formulation of the conclusion of this argument as "Whatever will happen will happen of necessity" is implausible, at least from the modern point of view, (ii), the formulation as "Whatever will happen will happen inevitably" is more to the point, and (iii), on the basis of the worldless and timeless aspect advocated in chapter 2, this latter formulation is quite harmless, essentially amounting to the trivial statement, "Whatever will happen will happen". Thirdly, in chapter 4 I study theological determinism, or determinism that arises from God's supposed providential control over everything that happens. In this connection, I shall survey some historical accounts of the relation between human free will and determinism (not only theological but also causal determinism); the philosophers the views of whom I shall attend to include Chrysippus, St. Augustine, Boethius and Aquinas. I shall in particular consider G.W. Leibniz' theodicean aspirations, viz. his solution to the problem of evil and, especially, his compatibilist attempts to reconcile human free will with the strictly deterministic flow of actual events. I think it is important to try to explicate Leibniz' ingenious account of these matters, since it seems that it has not been fully appreciated in the literature, not even by contemporary Leibniz scholars (such as B. Mates, R.C. Sleigh, C. Wilson, R.M. Adams and D. Rutherford). In providing the Leibnizian compatibilist solution of the problem of determinism and freedom in chapter 4, I shall utilize the approach of chapter 2. (shrink)

This article discusses some reasons for taking a reconstructive approach to the argumentative structure of Leibniz’s metaphysics. One reason is the fragmentary nature of the countless notes and letters that constitute by far the largest part of Leibniz‘s philosophical output. Another reason is that conjecturing how the many isolated arguments proposed by Leibniz fit into a large-scale argumentative structure could yield insights into how Leibniz made use of the method of intuition – both in his analysis of mind and in (...) his analysis of matter. Contemporary critics have objected that the method of intuition leads to philosophical conservatism, arbitrary choices between conflicting intuitions, and a preoccupation with psychological facts rather than with reality. By contrast, reconstructing the methodology behind Leibniz’s metaphysics could indicate how intuitions could be used in a way that sidesteps these problems. Leibniz gives priority to intuitions concerning the structure of mental operations over intuitions concerning the structure of material objects; this is why intuitions concerning the structure of material objects can be replaced by innovative philosophical theories; these theories, however, make use of metaphysical concepts implied by the analysis of mind and, thereby, can capture facts both about psychology and about the structure of extra-mental reality. (shrink)

This paper is intended to examine the distinction made by Leibniz in Generales Inquisitiones de Analysi Notionum et Veritatum between essential and existential propositions, in order to shed some light on the nature of the analogies that Leibniz proposes between the logical problem of contingency and the geometrical problem of the continuum.