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)

During the seventeenth century the major cognitive faculties--sense, imagination, memory, and understanding or intellect--became the central focus of argument in metaphysics and epistemology to an extent not seen before. The theory of the intellect, long an important auxiliary to metaphysics, became the focus of metaphysical dispute, especially over the scope and powers of the intellect and the existence of a `pure' intellect. Rationalist metaphysicians such as Descartes, Spinoza, and Malebranche claimed that intellectual knowledge, gained independently of the senses, provides the (...) framework for constructing a new theory of nature. Other writers, including Hobbes and the early Gassendi, denied the existence of a distinct intellectual faculty, and so challenged the metaphysicians' abilities directly to perceive the essences of substances. The theory of the senses, which had long been a part of philosophical discussion, took on a new urgency, for adherents of the new corpuscularian philosophy needed to replace the dominant Aristotelian theory of real sensory qualities and sensible species. The revival of skepticism and a renewed interest in method also brought the faculties into prominence, for skeptical challenges typically were directed toward the faculties of sense and understanding, and the theory of method was conceived as providing instructions for the proper use of one's cognitive equipment. The theory of the faculties, then, is an important key to theories of knowledge in the seventeenth century. Indeed, rather than speaking of seventeenth century epistemology, it would be less anachronistic and more informative to speak of theories of cognition. The familiar (and over-stated) point that epistemology became fundamental to metaphysics during that century can then be restated as the point that the theory of faculties became central in metaphysical dispute. (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)

(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.

The studies that make up this book were written and brought together to honor the memory of Jan Pinborg. His unexpected death in 1982 at the age of forty-five shocked and saddened students of medieval philosophy everywhere and left them with a keen sense of disappoint ment. In his fifteen-year career Jan Pinborg had done so much for our field with his more than ninety books, editions, articles, and reviews and had done it all so well that we recognized him (...) as a leader and counted on many more years of his scholarship, his help, and his friendship. To be missed so sorely by his international colleagues in an academic field is a mark of Jan's achievement, but only of one aspect of it, for historians of philosophy are not the only scholars who have reacted in this way to Jan's death. In his decade and a half of intense productivity he also acquired the same sort of special status among historians of linguistics, whose volume of essays in his memory is being G. L. Bursill-Hall almost simultane published under the editorship of ously with this one. Sten Ebbesen, Jan's student, colleague, and successor as Director of the Institute of Medieval Greek and Latin Philology at the University of Copenhagen, has earned the gratitude of all of us by memorializing Jan 1 in various biographical sketches, one of which is accompanied by a 2 complete bibliography of his publications. (shrink)

This paper reconstructs the development of Mersenne's reflections concerning optics. I argue that Mersenne's optical writings provide crucial insights into Mersenne's Aristotelianism. I reconstruct Mersenne's attempt of explaining the new ideas on light, which were advanced by Kepler, Descartes and Hobbes within Aristotle's natural philosophy. Mersenne explained Kepler's work on light within the Scholastic tradition. In the 1640s, Mersenne was stimulated by the debate concerning Descartes' theory of light, which he accepted only in 1648. Indeed, Mersenne first explained Descartes' law (...) of refraction by means of Hobbes physics. However, Mersenne always wanted to remain faithful to Aristotle. (shrink)

Este trabalho tem como objetivo tratar do papel da imaginação na filosofia política de Hobbes. Argumentamos que a reflexão de Hobbes sobre a imaginação conduz à distinção fundamental para sua filosofia política entre prudência e razão. A instituição da soberania consiste justamente na superação da dimensão da prudência através da razão. Assim, a filosofia política de Hobbes envolve a substituição de uma esfera de relações de poder, o plano da imaginação, por uma esfera de relações de direito no estado civil, (...) o plano da razão. (shrink)

The views of thirteenth century Catholic thinker Thomas Aquinas and twentieth century economist Milton Friedman on the social responsibility of business are contrasted by probing the foundations of their positions. The basis of Aquinas' normative stance in political economy is found in the metaphysical and moral realism of the classic tradition. The role Descartes and Hobbes played in overturning this philosophical starting point and ushering in an age of ideology is traced out. Friedman's commitment to Comte's vision of positivism is (...) revealed and what this entails for metaphysics, ethics, and economics is given. (shrink)