Stewart Duncan

Early in the eighteenth century Leibniz had several interactions with John Toland. These included discussions of materialism, which culminated with the consideration of Toland’s 1704 _Letters to Serena_. There Toland argued that matter is necessarily active. This chapter argues for two main theses about this exchange and its consequences for our wider understanding. First, despite many claims that Toland was at the time of _Letters to Serena_ a Spinozist, we can make better sense of him as a sort of Hobbesian materialist. The second main point concerns reasons for materialism, and in particular a story Locke tells in the _Essay_ about materialists’ motives and their use of conceivability arguments. Toland did use a conceivability argument, as indeed did Hobbes. But these were not the crude conceivability arguments that Locke suggests motivate materialists. We might tell a Lockean story about reasons for early modern materialism, but not Locke's story.

This chapter addresses the nominalism of Thomas Hobbes. It begins by examining the ways in which Hobbes presented and argued for nominalist views in a series of works, including _The Elements of Law_ (1641), _Leviathan_ (1651), and _De Corpore_ (1655). It then considers two prominent criticisms of Hobbes’s views. The first is a criticism from the seventeenth century, associated with the claim that Hobbes was an ultranominalist. This criticism, made by Descartes, More, and Leibniz, was that Hobbes’s view made it impossible for people speaking different languages to talk about the same thing. The second criticism, which has been prominent more recently, is that Hobbes fails to be a consistent nominalist, because his explanations appeal to similarity, and this appeal itself involves a universal.

This chapter investigates Locke’s views about materialism, by looking at the discussion in _Essay_ IV.x. There Locke—after giving a cosmological argument for the existence of God—argues that God could not be material, and that matter alone could never produce thought. In discussing the chapter, I pay particular attention to some comparisons between Locke’s position and those of two other seventeenth-century philosophers, René Descartes and Ralph Cudworth. Making use of those comparisons, I argue for two main claims. The first is that the important argument of _Essay_ IV.x.10 is fundamentally an argument about the causation of perfections. Indeed, Locke gives multiple such arguments in the chapter. My second main claim is that my proposed reading of IV.x is not merely consistent with what Locke says elsewhere about superaddition, but also provides reasons to favor a particular understanding of what superaddition is.

Draft for the Oxford Handbook of Margaret Cavendish (edited by Julie Crawford with Jacqueline Broad). This chapter looks at Margaret Cavendish's treatment of the supernatural, beginning by asking how she distinguishes the natural from the supernatural, and then by examining her treatment of a series of alleged supernatural beings: fairies, ghosts, witches, the human supernatural soul, angels, and God. Throughout, it argues that Cavendish's approach to the supernatural is often similar to Thomas Hobbes's.

In the _True Intellectual System_, Cudworth attacks types of atheist position—atomic atheism, hylozoic atheism, etc. He generally uses ancient examples to illustrate those types, but also criticizes some of his contemporaries. We can identify direct criticisms of contemporaries by finding quotations, paraphrases, and accounts of their views in the text. My primary question in this paper is, 'how much of the _True Intellectual System_ is directly about or aimed at Spinoza?' My ultimate answer, contrary to some prominent voices in the existing literature, is 'not very much at all'.

In his Enquiry concerning the Principles of Morals David Hume said that a group of earlier modern philosophers, beginning with Malebranche, held that morality was founded on relations. In this paper I follow up on that suggestion by investigating pre-Humean views in moral philosophy according to which morality is founded on relations. I do that by looking at the work of Nicolas Malebranche, John Locke, and Samuel Clarke. Each of them talked prominently about relations in their accounts of basic aspects of morality. Beyond that, each of them turns out to have held both metaphysical and epistemological views that might be described as founding morality on relations. Despite the definite differences between the three philosophers’ approaches, Hume does seem to have noticed a genuine connection here—even though he himself tended to ignore significant versions of this approach when criticizing it.

Thomas Hobbes often includes powers and abilities in his descriptions of the world. Meanwhile, Hobbes’s philosophical picture of the world appears quite reductive, and he seems sometimes to say that nothing exists but bodies in motion. In more extreme versions of such a picture, there would be no room for powers. Hobbes is not an eliminativist about powers, but his view does tend toward ontological minimalism. It would be good to have an account of what Hobbes thinks powers are, and how they fit into his understanding of the world. In this chapter, I investigate Hobbes’s account of the metaphysics of powers and abilities. Section 1 considers three important aspects of Hobbes’s account of powers: the connection between powers and causes; the modal aspects of powers; and the connection between powers and motions. Sections 2 and 3 then consider interpretive arguments about whether Hobbes identifies powers with underlying corporeal features.

This chapter looks at the discussion of materialism in John Locke’s Essay concerning Human Understanding, and then at parts of the Anglophone reaction to those discussions. It considers the early criticisms of Locke by Edward Stillingfleet and the anonymous author of three sets of Remarks on Locke’s Essay. It then looks at some other ways in which readers reacted to Locke’s discussions: the views of Anthony Collins and John Toland, which one might be tempted to think of as Lockean materialism; William Carroll’s reading of Locke as a Spinozistic materialist; and the dualistic Lockeanism of William Duncan’s Lockean logic textbook.

Are human beings purely material creatures, or is there something else to them, an immaterial part that does some (or all) of the thinking, and might even be able to outlive the death of the body? This book is about how a series of seventeenth-century philosophers tried to answer that question. It begins by looking at the views of Thomas Hobbes, who developed a thoroughly materialist account of the human mind, and later of God as well. All this is in obvious contrast to the approach of his contemporary René Descartes. After examining Hobbes’s materialism, the book considers the views of three of his English critics: Henry More, Ralph Cudworth, and Margaret Cavendish. Both More and Cudworth thought Hobbes’s materialism radically inadequate to explain the workings of the world, while Cavendish developed a distinctive, anti-Hobbesian materialism of her own. The second half of the book focuses on the discussion of materialism in John Locke’s Essay Concerning Human Understanding, arguing that we can better understand Locke’s discussion if we see how and where he is responding to this earlier debate. At crucial points Locke draws on More and Cudworth to argue against Hobbes and other materialists. Nevertheless, Locke did a good deal to reveal how materialism was a genuinely possible view, by showing how one could develop a detailed account of the human mind without presuming it was an immaterial substance.

This chapter considers Ralph Cudworth as a philosophical critic of Hobbes. Cudworth saw Hobbes as a representative of the three views he was attacking: atheism, determinism, and the denial that morality is eternal and immutable. Moreover, he did not just criticize Hobbes by assuming that a general critique of those views applied to Hobbes’s particular case. Rather, he singled out Hobbes, often by quoting him, and argued against the distinctively Hobbesian positions he had identified. In this chapter I look at Cudworth as a critic of Hobbes in two of the three central areas, atheism and ethics, focusing on passages where we see him explicitly picking out Hobbes.

This paper investigates Locke’s views about materialism, by looking at the discussion in Essay IV.x. There Locke---after giving a cosmological argument for the existence of God---argues that God could not be material, and that matter alone could never produce thought. In discussing the chapter, I pay particular attention to some comparisons between Locke’s position and those of two other seventeenth-century philosophers, René Descartes and Ralph Cudworth. Making use of those comparisons, I argue for two main claims. The first is that the important argument of Essay IV.x.10 is fundamentally an argument about the causation of perfections. Indeed, Locke gives multiple such arguments in the chapter. My second main claim is that my proposed reading of IV.x is not merely consistent with what Locke says elsewhere about superaddition, but also provides reasons to favor a particular understanding of what superaddition is.

We look at some interesting and important episodes in the life of early modern Epicureanism, focusing on natural philosophy. We begin with two early moderns who had a great deal to say about ancient Epicureanism: Pierre Gassendi and Ralph Cudworth. Looking at how Gassendi and Cudworth conceived of Epicureanism gives us a sense of what the early moderns considered important in the ancient tradition. It also points us towards three main themes of early modern Epicureanism in natural philosophy, which we then discuss at greater length: atomism, materialism about the mind or soul, and the denial of providence, which was often accompanied by deflationary explanations of religious belief.

Deborah Boyle's book is a splendid addition to the literature on the philosophy of Margaret Cavendish. It provides an overview of Cavendish's philosophical work, from her panpsychist materialism, through her views about human motivation and general political philosophy, to views about gender, health, and humans' relation to the rest of the natural world. Boyle emphasizes themes of order and regularity, but does not argue that there is a strong systematic connection between Cavendish's views. Indeed, she makes a point of noting the different ways in which the themes of order and regularity work in different areas of Cavendish's philosophy.The early chapters consider Cavendish's natural philosophy....

Gassendi and Hobbes knew each other, and their approaches to philosophy often seem similar. They both criticized the Cartesian epistemology of clear and distinct perception. Gassendi engaged at length with skepticism, and also rejected the Aristotelian notion of scientia, arguing instead for a probabilistic view that shows us how we can move on in the absence of certain and evident knowledge. Hobbes, in contrast, retained the notion of scientia, which is the best sort of knowledge and involves causal explanation. He thought, however, that this sort of knowledge was only available in geometry and political philosophy.

This dissertation discusses the work of Thomas Hobbes, and has two main themes. The first is Hobbes's materialism, and the second is Hobbes's relationships to other philosophers, in particular his place in the mechanist movement that is said to have replaced Aristotelianism as the dominant philosophy in the seventeenth century. I argue that Hobbes does not, for most of his career, believe the general materialist view that bodies are the only substances. He believes, rather, that ideas, which are our main mechanism for thinking about the world, allow us to understand many bodies, but not to understand every thing we recognize to exist. The incomprehensible things include God---and, early in Hobbes's career, the human mind. Discussing materialism and our knowledge of God leads me to engage with the debate over Hobbes's alleged atheism. I argue that the evidence for Hobbes's atheism is weak at best. Hobbes is a sincere theist, though his view is sometimes unusual. My discussion of Hobbes's relationships to other philosophers has three parts. In chapter five I argue that Hobbes's views about method are in important ways similar to Zabarella's. In chapter six I look at Hobbes's rejection of the view, held by some scholastic Aristotelians, that accidents can sometimes exist without inhering in substances. Thus we see two sides of Hobbes's interaction with the Aristotelian tradition. Sometimes that interaction is just rejection, but at other times Hobbes takes over views from that tradition. Then in chapter seven I consider whether, and in what sense, Hobbes is a mechanist. I argue that the narrative of mechanism and Aristotelianism is a less powerful explanation than it has seemed to some to be, because it is hard to see what mechanists have in common.

Leibniz's mill argument in 'Monadology' 17 is a well-known but puzzling argument against materialism about the mind. I approach the mill argument by considering other places where Leibniz gave similar arguments, using the same example of the machinery of a mill and reaching the same anti-materialist conclusion. In a 1702 letter to Bayle, Leibniz gave a mill argument that moves from his definition of perception (as the expression of a multitude by a simple) to the anti-materialist conclusion. Soon afterwards, in the Preface to the New Essays, Leibniz gave a different mill argument. That argument depends upon there being no arbitrary and inexplicable connections in nature, because God would not create such things. Later, in the 'Monadology', Leibniz again used the mill example in arguing against materialism. That passage too, I argue, uses an argument from inexplicability rather than from Leibniz's definition of perception.

Thomas Hobbes (1588-1679), whose current reputation rests largely on his political philosophy, was a thinker with wide ranging interests. In philosophy, he defended a range of materialist, nominalist, and empiricist views against Cartesian and Aristotelian alternatives. In physics, his work was influential on Leibniz, and lead him into disputes with Boyle and the experimentalists of the early Royal Society. In history, he translated Thucydides's History of the Peloponnesian War into English, and later wrote his own history of the Long Parliament. In mathematics he was less successful, and is best remembered for his repeated unsuccessful attempts to square the circle. But despite that, Hobbes was a serious and prominent participant in the intellectual life of his time.

I consider Leibniz's thoughts about Hobbes's materialism, focusing on his less-discussed later thoughts about the topic. Leibniz understood Hobbes to have argued for his materialism from his imagistic theory of ideas. Leibniz offered several criticisms of this argument and the resulting materialism itself. Several of these criticisms occur in texts in which Leibniz was engaging with the generation of British philosophers after Hobbes. Of particular interest is Leibniz's correspondence with Damaris Masham. Leibniz may have been trying to communicate with Locke, but ended up discussing Masham's version of the argument for materialism that Leibniz attributed to Hobbes.

Margaret Cavendish (1623-73) held a number of surprising philosophical views. These included a materialist panpsychism, and some views in what we might call environmental ethics. Panpsychism, though certainly not unheard of, is still often a surprising view. Views in environmental ethics - even just views that involve a measure of environmental concern - are unusual to find in early modern European philosophy. Cavendish held both of these surprising views. One might suspect that panpsychism provides some reasons for environmental concern. I argue, however, that Cavendish did not derive her environmental ethics from her panpsychism. If there is a connection, it is a developmental one, leading from the ethics to the panpsychism. The investigation of these issues also provides an occasion for thinking more generally about how Cavendish's views fit together, and whether she developed a systematic philosophy in the manner of several of her contemporaries.

Language was central to Hobbes's understanding of human beings and their mental abilities, and criticism of other philosophers' uses of language became a favorite critical tool for him. This paper connects Hobbes's theories about language to his criticisms of others' language, examining Hobbes's theories of propositions and truth, and how they relate to his claims that various sorts of proposition are absurd. It considers whether Hobbes in fact means anything more by 'absurd' than 'false'. And it pays particular attention to Hobbes's categorization of causes of absurdity and of types of incoherent proposition, arguing that Hobbes's approach is only loosely related to later discussions of category mistakes.

In the early years of the eighteenth century Leibniz had several interactions with John Toland. These included, from 1702 to 1704, discussions of materialism. Those discussions culminated with the consideration of Toland's 1704 Letters to Serena, where Toland argued that matter is necessarily active. In this paper I argue for two main theses about this exchange and its consequences for our wider understanding. The first is that, despite many claims that Toland was at the time of Letters to Serena a Spinozist, we can make better sense of him as a sort of Hobbesian materialist. The second main point concerns reasons for materialism, and in particular a story Locke tells in the Essay about materialists' motives. Toland defends his materialism by arguing that matter is active, and argues that matter is active by using a conceivability argument. But this is not the crude conceivability argument that Locke suggests motivates materialists. This (together with reflecting on some of Hobbes's arguments) suggests that we might well tell a Lockean story about reasons for early modern materialism, but not Locke's story.

Leibniz frequently uses the notion of expression, but it is not easy to see just how he understood that relation. This paper focuses on the particular case of the expression of God, which is prominent in the 'Discourse on Metaphysics'. The treatment of expression there suggests several questions. Which substances did Leibniz believe expressed God? Why did Leibniz believe those substances expressed God? And did he believe that all substances expressed God in the same way and for the same reasons? In answering those questions the paper distinguishes two views about expression in the 'Discourse', considers Leibniz's reasons for holding that substances express their causes, and argues that Leibniz's views about emanative causation are important for understanding the unity of his apparently distinct views here. The paper concludes by looking briefly at how the 'Discourse' fits into the evolution of Leibniz's views on this issue over time.

Leibniz's correspondence with Thomas Burnett of Kemnay is probably best known for Leibniz's attempts to communicate with Locke via Burnett. But Burnett was also, more generally a source of English intellectual news for Leibniz. As such, Burnett provided an important part of the context in which Locke was presented to and understood by Leibniz. This paper examines the Leibniz-Burnett correspondence, and argues against Jolley's suggestion that "the context in which Leibniz learned about Locke was primarily a theological one". That said, in thinking about Locke's Reasonableness of Christianity, and his subsequent defenses of it, Leibniz does offer an argument against Locke's book -- but not one that's closely related to Locke's theological views, or to any accusation of Socinianism. The paper also considers, by way of contrast, the way Leibniz and Burnett talk about the more obviously controversial figure John Toland.