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)

An introduction to Thomas Hobbes as a systematic and not merely political philosopher. Best known for his contributions to political philosophy, Thomas Hobbes set out to develop a coherent philosophical system extending from logic and natural philosophy to civil and religious philosophy. In this introduction to Hobbes’s thought, Otfried Höffe begins by providing an overview of the entire scope of his work, making clear its systematic character through analysis of his natural philosophy, his individual and social anthropology, and his political (...) thought. He then offers an innovative examination of religious and ecclesiastical questions, touching not only on the political implications of religion so important to Hobbes, but also on his attempt to reconstruct Christianity in terms of a materialistic philosophy. He also explores Hobbes’s continuous critique of Aristotle and Aristotelian Scholastics, in which Höffe argues that Hobbes and Aristotle have much more in common philosophically than is normally supposed—and certainly more than Hobbes himself acknowledged. Finally, Höffe sketches the influence Hobbes had and continues to have on the development of legal and political philosophy. “A thoroughly successful introduction to the philosophy of Thomas Hobbes ” — Reinhard Brandt, in Süddeutsche Zeitung, in praise of the German edition. (shrink)

Thomas Hobbes of Malmesbury, one of the greatest philosophers of law and state, died 250 years ago, on December 4, 1679. His name was so frequently associated with a certain unfortunate conception of his moral and political philosophy, that the public's lack of interest in this centenary is not to be wondered at. So far, even amongst the scholars who admitted his merits, few tried to penetrate into the depths of his thought, and only at the end of the last (...) century, thanks to the writings of Ferdinand Tönnies and George Croom Robertson, was a new impulse given to research into Hobbes’ spiritual heritage. A series of monographies was published, and the personality of Hobbes appeared in a new light. His theories, when better known, proved to be less crude and more human than they had seemed, for they are a reaction from the revolutionary tendencies of his time. (shrink)

ABSTRACT: Hobbes belonged to philosophical and scientific circles grappling with the big question at the dawn of modern physics: materialism and its consequences for morality. ‘Matter in motion’ may be a core principle of this materialism but it is certainly inadequate to capture the whole project. In wave after wave of this debate the Epicurean view of a fully determined universe governed by natural laws, that nevertheless allows to humans a sphere of libertas, but does not require a creator god (...) or teleology to explain it, comes up against monotheism and its insistence on the incoherence of an ordered world in the absence of a God and his purposes. The following questions were central to this debate: Can we understand the universe as law-governed in the absence of a god? If so, what room is there in a fully determined mechanical universe for human freedom? If humans do enjoy freedom, does the same hold for other animals? Is this freedom compatible with standard views of morality? (shrink)

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)

In spite of vigorous opposition by a number of historians it has now become a commonplace that the rapid development of the ‘new philosophy’ sprang from the ideology of Puritanism. What began its career as the ‘Merton thesis’ has now been refined, developed, and so often repeated that it seems to be almost unassailable. However, the two foremost historians in the entrenchment of this new orthodoxy are willing, in principle, to concede that ‘in reality things were very mixed up’, and (...) that non-Puritan natural philosophers at the time were operating ‘in a precisely similar manner’ to their Puritan contemporaries. Indeed, it would be impossible not to concede this in the face of the many critiques launched against the Merton thesis. (shrink)

This paper explores Thomas Hobbes’s account of animal life and mind. After a critical examination of Hobbes’s mechanistic explanation of operations of the mind such as perception and memory, I argue that his theory derives its strength from his idea of the dynamic interaction of the body with its surroundings. This dynamic interaction allows Hobbes to maintain that the purposive disposition of the animal is not merely an upshot of its material configuration, but an expression of its distinctive bodily history. (...) In support of Hobbes, I show how this is complemented by his account of the unity and continuity of the animal body in terms of a unification through the self-preserving drive that originates in perception. Nonetheless, I argue that Hobbes’s philosophy of animal life and mental faculties is hindered by a kind of epiphenomenalist perspective that is embedded in his materialist framework, and this perspective leaves the status of ideas and mental content unclear. I explain why Hobbes’s dynamic theory, founded upon the reciprocal determination of moving bodies, supports his idea of animal development and habituation while failing to account for the reflexivity of the mind. (shrink)

This paper aims both to tackle the technical issue of deciphering Hobbes’s derivation of the sine law of refraction and to throw some light to the broader issue of Hobbes’s mechanical philosophy. I start by recapitulating the polemics between Hobbes and Descartes concerning Descartes’ optics. I argue that, first, Hobbes’s criticisms do expose certain shortcomings of Descartes’ optics which presupposes a twofold distinction between real motion and inclination to motion, and between motion itself and determination of motion; second, Hobbes’s optical (...) theory presented in Tractatus Opticus I constitutes a more economical alternative, which eliminates the twofold distinction and only admits actual local motion, and Hobbes’s derivation of the sine law presented therein, which I call “the early model” and which was retained in Tractatus Opticus II and First Draught, is mathematically consistent and physically meaningful. These two points give Hobbes’s early optics some theoretical advantage over that of Descartes. However, an issue that has baffled commentators is that, in De Corpore Hobbes’s derivation of the sine law seems to be completely different from that presented in his earlier works, furthermore, it does not make any intuitive sense. I argue that the derivation of the sine law in De Corpore does make sense mathematically if we read it as a simplification of the early model, and Hobbes has already hinted toward it in the last proposition of Tractatus Opticus I. But now the question becomes, why does Hobbes take himself to be entitled to present this simplified, seemingly question-begging form without having presented all the previous results? My conjecture is that the switch from the early model to the late model is symptomatic of Hobbes’s changing views on the relation between physics and mathematics. (shrink)