In Metaphysical Themes, Robert Pasnau interprets Thomas Hobbes as an anti-realist about all accidents in general. In opposition to Pasnau, we argue that Hobbes is a realist about some accidents (e.g., motion and magnitude). Section One presents Pasnau’s position on Hobbes; namely, that Hobbes is an unqualified anti-realist of the eliminativist sort. Section Two offers reasons to reject Pasnau’s interpretation. Hobbes explains that magnitude is mind-independent, and he offers an account of perception in terms of motion (understood as a mind-independent (...) feature of body). Therefore, it seems incorrect to call Hobbes an anti-realist about all accidents. Section Three considers Pasnau’s hypothetical response: he might claim that for Hobbes, motion reduces to body and does not exist in its own right. Section Four notes that reductionism about all accidents does not entail anti-realism about all accidents. Even granting Pasnau’s anticipated response, his anti-realist reading does not follow. Contra Pasnau, Hobbes is best understood as claiming that motion and magnitude exist mind-independently. (shrink)

(2013). The Theological Foundation of Hobbesian Physics: A Defence of Corporeal God. British Journal for the History of Philosophy: Vol. 21, No. 2, pp. 240-261. doi: 10.1080/09608788.2012.692663.

Accounts of Hobbes’s ‘system’ of sciences oscillate between two extremes. On one extreme, the system is portrayed as wholly axiomtic-deductive, with statecraft being deduced in an unbroken chain from the principles of logic and first philosophy. On the other, it is portrayed as rife with conceptual cracks and fissures, with Hobbes’s statements about its deductive structure amounting to mere window-dressing. This paper argues that a middle way is found by conceiving of Hobbes’s _Elements of Philosophy_ on the model of a (...) mixed-mathematical science, not the model provided by Euclid’s _Elements of Geometry_. I suggest that Hobbes is a test case for understanding early-modern system-construction more generally, as inspired by the structure of the applied mathematical sciences. This approach has the additional virtue of bolstering, in a novel way, the thesis that the transformation of philosophy in the long seventeenth century was heavily indebted to mathematics, a thesis that has increasingly come under attack in recent years. (shrink)

I offer an alternative account of the relationship of Hobbesian geometry to natural philosophy by arguing that mixed mathematics provided Hobbes with a model for thinking about it. In mixed mathematics, one may borrow causal principles from one science and use them in another science without there being a deductive relationship between those two sciences. Natural philosophy for Hobbes is mixed because an explanation may combine observations from experience (the ‘that’) with causal principles from geometry (the ‘why’). My argument shows (...) that Hobbesian natural philosophy relies upon suppositions that bodies plausibly behave according to these borrowed causal principles from geometry, acknowledging that bodies in the world may not actually behave this way. First, I consider Hobbes's relation to Aristotelian mixed mathematics and to Isaac Barrow's broadening of mixed mathematics in Mathematical Lectures (1683). I show that for Hobbes maker's knowledge from geometry provides the ‘why’ in mixed-mathematical explanations. Next, I examine two explanations from De corpore Part IV: (1) the explanation of sense in De corpore 25.1-2; and (2) the explanation of the swelling of parts of the body when they become warm in De corpore 27.3. In both explanations, I show Hobbes borrowing and citing geometrical principles and mixing these principles with appeals to experience. (shrink)

Many of Margaret Cavendish’s criticisms of Thomas Hobbes in the Philosophical Letters (1664) relate to the disorder and damage that she holds would result if Hobbesian pressure were the cause of visual perception. In this paper, I argue that her “two men” thought experiment in Letter IV is aimed at a different goal: to show the explanatory potency of her account. First, I connect Cavendish’s view of visual perception as “patterning” to the “two men” thought experiment in Letter IV. Second, (...) I provide a potential reply on Hobbes’s behalf that appeals to physiological differences between perceivers’ sense organs, drawing upon Hobbes’s optics in De homine. Third, I argue that such a reply would misunderstand Cavendish’s objective of showing the limited explanatory resources available in understanding visual perception as pressing when compared to her view of visual perception as patterning. (shrink)