It's well known that Leibniz characterizes bodies in two apparently incompatible ways. On the one hand, he asserts that a body is a real or well-founded phenomenon; on the other, he claims that a body is an aggregate of substances that possesses the reality of these same substances. In this essay I aim to defend an explanation of the relation that exists, according to Leibniz, between these two conceptions of body, an explanation that shows them to be compatible and, indeed, (...) complementary. In the first part of this paper I aim above all to show that Robert Adams and Donald Rutherford are wrong to think that these two conceptions are to be reconciled by recognizing that for Leibniz they apply to one and the same thing. (shrink)

I argue that Leibniz consistently subscribes to the view that phenomena (thus bodies) have their being in perceiving substances. I then argue that this mentalistic conception of phenomenon coheres with three of his doctrines of body: (1) that bodies presuppose the unities or simple substances on which they are founded; (2) that bodies are aggregates of those substances; and (3) that bodies derive or borrow their reality from their simple constituents.

Kant and Leibniz are interested in explaining how a number of individuals can come together and form a single unified composite substance. Leibniz does not have a convincing account of how this is possible. In his pre-critical writings and in his later metaphysics lectures, Kant is committed to the claim that the idea of a world is the idea of a real whole, and hence is the idea of a composite substance. This metaphysical idea is taken over into his ethical (...) writings and becomes the idea of a realm of ends. I explain why a realm of ends, should be thought of as both a unum per se and as a real whole. A realm of ends is a whole of individuals unified by laws they have given themselves, that is, it is a community of autonomous individuals. Only such a community can be thought of as a composite individual. Such a whole will be real rather than ideal because the source of the unity of the whole is intrinsic to the whole, for what gives unity to the realm are laws and the sources of the laws are the individual members of the whole. It will be a unum per se because both the laws and the individuals constituting the realm are incomplete without one another. If this reading is correct, this requires a fundamental reevaluation of Kant’s notion of autonomy. To be autonomous is not, primarily, to be understood in terms of ruling oneself, but instead must be thought of primarily in terms of being a generative source of laws for an ideal community. (shrink)

Gottfried Wilhelm Leibniz (1646–1716) was one of the great thinkers of the seventeenth and eighteenth centuries and is known as the last “universal genius”. He made deep and important contributions to the fields of metaphysics, epistemology, logic, philosophy of religion, as well as mathematics, physics, geology, jurisprudence, and history. Even the eighteenth century French atheist and materialist Denis Diderot, whose views could not have stood in greater opposition to those of Leibniz, could not help being awed by his achievement, writing (...) in his Encyclopedia, “Perhaps never has a man read as much, studied as much, meditated more, and written more than Leibniz… What he has composed on the world, God, nature, and the soul is of the most sublime eloquence. If his ideas had been expressed with the flair of Plato, the philosopher of Leipzig would cede nothing to the philosopher of Athens.” (Vol. 9, p. 379) Indeed, Diderot's mood was almost despairing in a remark from another piece, which also has a great deal of truth in it: “When one compares the talents one has with those of a Leibniz, one is tempted to throw away one's books and go die quietly in the dark of some forgotten corner.” More than a century later, Gottlob Frege, who fortunately did not cast his books away in despair, expressed similar admiration, declaring that “in his writings, Leibniz threw out such a profusion of seeds of ideas that in this respect he is virtually in a class of his own.” (“Boole's logical Calculus and the Concept script” in Posthumous Writings , p. 9) The aim of this entry is primarily to introduce Leibniz's life and summarize and explicate his views in the realms of metaphysics, epistemology, philosophical theology, and natural philosophy. (shrink)

This essay offers an account of the relationship between extended Leibnizian bodies and unextended Leibnizian monads, an account that shows why Leibniz was right to see intimate, explanatory connections between his studies in physics and his mature metaphysics. The first section sets the stage by introducing a case study from Leibniz's technical work on the strength of extended, rigid beams. The second section draws on that case study to introduce a model for understanding Leibniz's views on the relationship between derivative (...) and primitive forces. The third section draws on Leibniz's understanding of the relationship between derivative and primitive forces in order to shed light, in turn, on his understanding of the relationship between extended, material bodies and unextended, immaterial monads. The fourth section responds to a likely objection by arguing that Leibniz's monads may, in a perfectly reasonable sense, be spatially located. (shrink)

According to Leibniz's late metaphysics, sensory perception represents to us as extended, colored, textured, etc., a world which fundamentally consists only of non-spatial, colorless entities, the monads. It is a short step from here to the conclusion that sensory perception radically misleads us about the true nature of reality. In this paper, I argue that this oft-repeated claim is false. Leibniz holds that in typical cases of body perception the bodies perceived really exist and have the qualities, both primary and (...) secondary, they are perceived to have. At the same time, Leibniz holds that our perceptions of these bodies are accurate representations of the monads from which the bodies result. The contrary thesis — that our body perceptions are misrepresentations of the monads — stems from a misunderstanding of Leibniz's theory of confused concepts and his phenomenalist account of the nature of body. Clarifying these issues will have important consequences for our understanding of Leibniz's idealistic metaphysics and the manner in which that metaphysical theory is meant to support mechanistic science. (shrink)