Drawing on remarks scattered through his writings, I argue that Leibniz has a highly distinctive and interesting theory of color. The central feature of the theory is the way in which it combines a nuanced subjectivism about color with a reductive approach of a sort usually associated with objectivist theories of color. After reconstructing Leibniz's theory and calling attention to some of its most notable attractions, I turn to the apparent incompatibility of its subjective and reductive components. I argue that (...) this apparent tension vanishes in light of his rejection of a widely accepted doctrine concerning the nature of bodies and their geometrical qualities. (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)

Leibniz claims that Berkeley “wrongly or at least pointlessly rejects abstract ideas”. What he fails to realize, however, is that some of his own core views commit him to essentially the same stance. His belief that this is the best (and thus most harmonious) possible world, which itself stems from his Principle of Sufficient Reason, leads him to infer that mind and body must perfectly represent or ‘express’ one another. In the case of abstract thoughts he admits that this can (...) happen only in virtue of thinking of some image that, being essentially a mental copy of a brain state, expresses (and is expressed by) that state. But here he faces a problem. In order for a thought to be genuinely abstract, its representational content must differ from that of any mental image, since the latter can represent only particular things. In that case, however, an exact correspondence between the accompanying mental image and the brain state would not suffice to establish a perfect harmony between mind and body. Even on Leibniz’s own principles, then, it appears that Berkeley was right to dismiss abstract ideas. (shrink)

One of the most pressing philosophical problems in early modern Europe concerned how the soul and body could form a unity, or, as many understood it, how these two substances could work together. It was widely believed that there were three (and only three) hypotheses regarding the union of soul and body: (1) physical influence, (2) occasionalism, and (3) pre-established harmony. However, in 1763, a fourth hypothesis was put forward by the French thinker André-Pierre Le Guay de Prémontval (1716–1764). Prémontval’s (...) hypothesis, given the grand name of “psychocracy” (i.e., the dominion or the rule of the soul), held that there was a real influence between soul and body, but that this was an immaterial kind of influence as opposed to the physical kind that had been entertained heretofore. Prémontval’s hypothesis is the focus of this paper. I shall begin by sketching out the details of Prémontval’s hypothesis (Section 1), then proceed to consider its claims to constitute a true fourth hypothesis distinct from the other three (Section 2), before closing by briefly considering two objections and the responses either that Prémontval himself made or that may be made on his behalf (Section 3). (shrink)

Leibniz holds that created substances do not causally interact with each other but that there is causal activity within each such creature. Every created substance constantly changes internally, and each of these changes is caused by the substance itself or by its prior states. Leibniz describes this kind of intra-substance causation both in terms of final causation and in terms of efficient causation. How exactly this works, however, is highly controversial. I will identify what I take to be the major (...) interpretive issues surrounding Leibniz's views on causation and examine several influential interpretations of these views. In ‘Leibniz on Causation – Part 2’ I will then take a closer look at final causation. (shrink)

This paper explores the theory of freedom that Emilie du Châtelet advances in her essay “On Freedom.” Using contemporary terminology, we can characterize this theory as a version of agent-causal compatibilism. More specifically, the theory has the following elements: (a) freedom consists in the power to act in accordance with one’s choices, (b) freedom requires the ability to suspend desires and master passions, (c) freedom requires a power of self-motion in the agent, and (d) freedom is compatible with moral necessity (...) but not with physical necessity. While these elements may at first appear disparate, the paper shows that they fit together quite well. The resulting theory is a surprising combination of doctrines that appear to be based on Samuel Clarke’s libertarian account of free will and doctrines that are reminiscent of the compatibilist accounts of John Locke, Anthony Collins, Gottfried Leibniz, and Thomas Hobbes. (shrink)

This article aims to make further progress in revising the standard account of Wolff’s philosophy as a popularisation and systematisation of Leibniz’s doctrines. It focuses on the topic of the communication among substances and the metaphysics of simples and activity underlying it. It is argued that Wolff does not accept the pre-established harmony in its orthodox Leibnizian version. The article explains Wolff’s departure from Leibniz’s PEH as stemming from his rejection of Leibniz’s construal of the activity of every simple as (...) representational power and of the metaphysics of unity and activity in which that construal is rooted. (shrink)