“Hobbes on the Signification of Evaluative Language”. Forthcoming in Hobbes Studies 32(2) (2019). In both the Elements of Law and Leviathan, Hobbes argues that a wide variety of terms – including ‘good’, ‘bad’, and the names of virtues and vices – have a double and inconstant signification. This paper explores and explains that theory of Hobbes’s. This phenomenon is, Hobbes thinks, pervasive in our use of moral and political language. Indeed he says his analysis applies to all “names of such things as affect us, that is, which please, and displease us” (Leviathan 4.24), which seems a very broad category indeed. This inconstancy of signification has considerable potential to cause confusion and conflict. Given those practical consequences, it is of some importance for Hobbes to find a solution to this problem. The paper examines several possible Hobbesian solutions to the problem. There is, however, reason to think that these suggested solutions cannot completely solve the problem.

Review of Deborah A. Boyle, The Well-Ordered Universe: The Philosophy of Margaret Cavendish (Oxford University Press, 2018). Forthcoming in Journal of the History of Philosophy 57(2) (2019).

Stewart Duncan and Antonia LoLordo, “Gassendi and Hobbes on Knowledge”. In Stephen Gaukroger (ed.), Knowledge in Modern Philosophy (Bloomsbury, 2018). 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.

Review of Margaret Cavendish, Observations upon Experimental Philosophy: Abridged, with Related Texts, edited by Eugene Marshall (Indianapolis: Hackett, 2016). British Journal for the History of Philosophy 26 (2018) 617-9.

Review of Jonathan S. Marko, Measuring the Distance between Locke and Toland. Locke Studies 18 (2018).

“Toland and Locke in the Leibniz-Burnett Correspondence”Locke Studies 17 (2017) 117-41. 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.

“Hobbes, Universal Names, and Nominalism”. In Stefano Di Bella & Tad M. Schmaltz (eds.), The Problem of Universals in Early Modern Philosophy (Oxford University Press, 2017). Thomas Hobbes was, rather famously, a nominalist. The core of that nominalism is the belief that the only universal things are universal names: there are no universal objects, or universal ideas. This paper looks at what Hobbes’s views about universal names were, how they evolved over time, and how Hobbes argued for them. The remainder of the paper considers two objections to Hobbes’s view: a criticism made by several of Hobbes’s contemporaries, that Hobbes’s view could not account for people saying the same thing in different languages; and a more recently popular criticism of Hobbes, that his nominalism’s reliance on similarity implicitly (and inconsistently) involves reliance on a universal.

“Materialism and the Activity of Matter in Seventeenth-Century European Philosophy”Philosophy Compass 11 (2016) 671-80. Early modern debates about the nature of matter interacted with debates about whether matter could think. In particular, some philosophers (e.g., Cudworth and Leibniz) objected to materialism about the human mind on the grounds that matter is passive, thinking things are active, and one cannot make an active thing out of passive material. This paper begins by looking at two seventeenth-century materialist views (Hobbes’s, and one suggested but not endorsed by Locke) before considering that objection (which I call here the Activity Argument). In discussion, I note that several philosophers of the time believed that matter was active. That view opens up a possible response to the Activity Argument. The paper concludes by looking at the views of two materialists of the time who also believed that matter was active, Toland and Cavendish.

“Hobbes on Language: Propositions, Truth, and Absurdity”. In A. P. Martinich & Kinch Hoekstra (eds.), The Oxford Handbook of Hobbes (Oxford University Press, 2016) 57-72. 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.

“Mind and Body in Modern Philosophy”. Routledge Encyclopedia of Philosophy Online (2016). A survey of the issue. Topics include Descartes; early critics of Descartes; occasionalism and pre-established harmony; materialism; idealism; views about animal minds; and simplicity.

“Leibniz on the Expression of God“. Ergo 2 (2015) 83-103. 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 may be helpful for understanding the unity of his apparently distinct views here.

“Comments on Larry May, Limiting Leviathan“. Hobbes Studies 27 (2014) 185-90. This paper discusses two aspects of Larry May’s book Limiting Leviathan. First it discusses a passage in Leviathan, to which May draws attention, in which Hobbes connects obligation to “that, which in the disputations of scholars is called absurdity”. Secondly it looks at the book’s discussion of Hobbes and pacifist attitudes, with reference to Hobbes’s contemporary critic John Eachard.

Stewart Duncan and Antonia LoLordo (ed.), Debates in Modern Philosophy: Essential Readings and Contemporary Responses (Routledge, 2013).

“Materialism”. In S. A. Lloyd (ed.), Bloomsbury Companion to Hobbes (Continuum, 2013). This is a short (1,250 word) introduction to Hobbes’s materialism, covering (briefly) such issues as what the relevant notion of materialism is, Hobbes’s debate with Descartes, and what Hobbes’s arguments for materialism were.

“Debating Materialism: Cavendish, Hobbes, and More”. History of Philosophy Quarterly 29 (2012) 391-409. This paper discusses the materialist views of Margaret Cavendish, focusing on the relationships between her views and those of two of her contemporaries, Thomas Hobbes and Henry More. It argues for two main claims. First, Cavendish’s views sit, often rather neatly, between those of Hobbes and More. She agreed with Hobbes on some issues and More on others, while carving out a distinctive alternative view. Secondly, the exchange between Hobbes, More, and Cavendish illustrates a more general puzzle about just what divided materialists from their opponents. Seemingly straightforward disagreements about whether incorporeal substances exist turn out to be more complex ones in which the nature of those things is disputed at the same time as their existence.

“Leibniz’s Mill Arguments Against Materialism”. Philosophical Quarterly 62 (2012) 250-72. 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.

“Toland, Leibniz, and Active Matter”. Oxford Studies in Early Modern Philosophy 6 (2012) 249-78. 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.

“Hobbes, Signification, and Insignificant Names”. Hobbes Studies 24 (2011) 158-178. The notion of signification is an important part of Hobbes’s philosophy of language. It also has broader relevance, as Hobbes argues that key terms used by his opponents are insignificant. However Hobbes’s talk about names’ signification is puzzling, as he appears to have advocated conflicting views. This paper argues that Hobbes endorsed two different views of names’ signification in two different contexts. When stating his theoretical views about signification, Hobbes claimed that names signify ideas. Elsewhere he talked as if words signified the things they named. Seeing this does not just resolve a puzzle about Hobbes’s statements about signification. It also helps us to understand how Hobbes’s arguments about insignificant speech work. With one important exception, they depend on the view that names signify things, not on Hobbes’s stated theory that words signify ideas. The paper concludes by discussing whether arguments about insignificant speech can provide independent support for Hobbes’s views about other issues, such as materialism.

“Leibniz on Hobbes’s Materialism”. Studies in History and Philosophy of Science Part A 41 (2010) 11-18. 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.

Review of Perez Zagorin, Hobbes and the Law of Nature. Notre Dame Philosophical Reviews (2010).

“Thomas Hobbes”. Stanford Encyclopedia of Philosophy (2009). 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.

“Hume and a Worry About Simplicity”. History of Philosophy Quarterly 26 (2009) 139-157. I discuss Hume’s views about whether simplicity and generality are positive features of explanations. In criticizing Hobbes and others who base their systems of morality on self interest, Hume diagnoses their errors as resulting from a “love of simplicity”. These worries about whether simplicity is a positive feature of explanations emerge in Hume’s thinking over time. But Hume does not completely reject the idea that it’s good to seek simple explanations. What Hume thinks we need is good judgment about when we are going too far in our search for simple explanations. These worries about simplicity are not unique to Hume. We can see versions of them in the work of Hutcheson, Smith, and Reid.

Review of James R. Martel, Subverting the Leviathan. Restoration, Studies in English Literary Culture, 1660-1700. 33 (2009) 57-9.

Review of Samantha Frost, Lessons From a Materialist Thinker: Hobbesian Reflections on Ethics and Politics. Notre Dame Philosophical Reviews (2008).

Review of Tom Sorell and Luc Foisneau (Ed.), Leviathan After 350 Years. Philosophical Quarterly 56 (2006) 614-6.

“Hobbes’s Materialism in the Early 1640s”. British Journal for the History of Philosophy 13 (2005) 437-448.. I argue that Hobbes isn’t really a materialist in the early 1640s (in, e.g., the Third Objections to Descartes’s Meditations). That is, he doesn’t assert that bodies are the only substances. However, he does think that bodies are the only substances we can think about using imagistic ideas.

“Knowledge of God in Leviathan”. History of Philosophy Quarterly 22 (2005) 31-48.. Hobbes denies in Leviathan that we have an idea of God. He does think, though, that God exists, and does not even deny that we can think about God, even though he says we have no idea of God. There is, Hobbes thinks, another cognitive mechanism by means of which we can think about God. That mechanism allows us only to think a few things about God though. This constrains what Hobbes can say about our knowledge of God, and grounds his belief in a fairly strong version of the thesis that God is incomprehensible.