_ Source: _Volume 29, Issue 1, pp 39 - 65 Since Euclid, optics has been considered a geometrical science, which Aristotle defines as a “mixed” mathematical science. Hobbes follows this tradition and clearly places optics among physical sciences. However, modern scholars point to a confusion between geometry and physics and do not seem to agree about the way Hobbes mixes both sciences. In this paper, I return to this alleged confusion and intend to emphasize the peculiarity of (...) class='Hi'>Hobbes’s geometrical optics. This paper suggests that Hobbes’s conception of geometrical optics, as a mixed mathematical science, greatly differs from Descartes’s one, mainly because they do not share the same “mechanical conception of nature.” I will argue that Hobbes and Descartes also have in common the quest for a different kind of geometry for their optics, different from that of the Ancients. I will show that this departure is not recent since Hobbes’s approach is already evident in 1636, when he judges the demonstrations of his contemporary friends, Claude Mydorge and Walter Warner. Finally the paper broadly suggests what is noteworthy in Hobbes’s optics, that is, the importance of the idea of force in his mechanics, although he was not able to conceptualize it in other terms than “quickness.”. (shrink)

_ Source: _Volume 29, Issue 1, pp 86 - 102 The aim of this paper is to give an overview of the place that Hobbes assigns to optics in the context of his classification of sciences and disciplinary boundaries. To do this, I will begin with an account of Hobbes’s conception of philosophy or science, and particularly his distinction between true and hypothetical knowledge. I will also show that in his demarcation between mathematics or geometry and natural philosophy (...) Hobbes was influenced by Galileo’s _Dialogue_. I then analyse the consequences of this distinction for optics, and conclude by clarifying its status among the scientific disciplines. (shrink)

This chapter discusses Thomas Hobbes's statements about the structure of philosophy and suggests that a focus on these reflections has led some scholars to understand Hobbes as an armchair speculative philosopher, both in his own natural‐philosophy endeavors and his well‐known criticisms of Robert Boyle and other experimental philosophers. Beyond Hobbes's statements about natural philosophy, it argues that a more complete understanding of his natural philosophy must also consider his practice of explaining in natural philosophy and optics. Hobbes divides all (...) human knowledge into two parts: scientia, and cognition. These two parts provide different levels of certainty to knowers. The chapter shows that explanations in optics and natural philosophy are ideally a mixture of appeals to everyday sense experience and Hobbes's own a priori geometry by providing two case studies: a case study from Hobbes's optics in De homine II and a case study of Hobbes's explanation of sense in De corpora XXV. (shrink)

This paper deals with Hobbes's theory of optical images, developed in his optical magnum opus, ‘A Minute or First Draught of the Optiques’, and published in abridged version in De homine. The paper suggests that Hobbes's theory of vision and images serves him to ground his philosophy of man on his philosophy of body. Furthermore, since this part of Hobbes's work on optics is the most thoroughly geometrical, it reveals a good deal about the role of mathematics in Hobbes's (...) philosophy. The paper points to some difficulties in the thesis of Shapin and Schaffer, who presented geometry as a ‘paradigm’ for Hobbes's natural philosophy. It will be argued here that Hobbes's application of geometry to optics was dictated by his metaphysical and epistemological principles, not by a blind belief in the power of geometry. Geometry supported causal explanation, and assisted reason in making sense of appearances by helping the philosopher understand the relationships between the world outside us and the images it produces in us. Finally the paper broadly suggests how Hobbes's theory of images may have triggered, by negative example, the flourishing of geometrical optics in Restoration England. (shrink)

Several recent commentators argue that Thomas Hobbes’s account of the nature of science is conventionalist. Engaging in scientific practice on a conventionalist account is more a matter of making sure one connects one term to another properly rather than checking one’s claims, e.g., by experiment. In this paper, I argue that the conventionalist interpretation of Hobbesian science accords neither with Hobbes’s theoretical account in De corpore and Leviathan nor with Hobbes’s scientific practice in De homine and elsewhere. (...) Closely tied to the conventionalist interpretation is the deductivist interpretation, on which it is claimed that Hobbes believed sciences such as optics are deduced from geometry. I argue that Hobbesian science places simplest conceptions as the foundation for geometry and the sciences in which we use geometry, which provides strong evidence against both the conventionalist and deductivist interpretations. (shrink)

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)

Hobbes's interest in the power of the Image was programmatic, as suggested by his shifts from optics, to sensationalist psychology, to the strategic use of classical history, exemplified by Thucydides and Homer. It put a great resource at the disposal of the state-propaganda machine, with application to the question of state-management and crowd control.

This chapter contains section titled: Three Contributions to Science The New Optics The New Science of Natural Justice All of Science Taught from the Elements.

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)

More than once in his writings, Hobbes pronounced on the scope and organization of science. He had provocative views about the subjects that could be termed “scientific” about the scientific subjects that were basic, and about the relative benefits of the various sciences. Some of these views reflect his allegiance to the new mechanical philosophy and his opposition to Aristotelianism; others show the influence of Bacon, who was a virtuoso deviser of blueprints for science. Still others belong to a program (...) of self-advertisement: Hobbes wished to be seen as an important scientist himself - an important worker in the field of optics and no less than the inventor of the science of politics. After expounding Hobbes's views about the organization of science and considering some of the problems they raise, I shall suggest that they throw light on old questions about what has been called “Hobbes's system”. (shrink)

Thomas Hobbes adheres to a conception of philosophy as causal knowledge that bears the mark of the Aristotelian tradition, as Cees Leijenhorst has elaborated in another issue of The Monist. Referring to Aristotle, Hobbes states explicitly in two mathematical studies of the 1660’s: “To know is to know by causes.” But according to Hobbes, we encounter obstacles when we search for causes in the field of natural philosophy. Consequently, his well-known definition of philosophy consists of two parts. The earliest version, (...) elaborated in the so-called A 10 manuscript, reads: “Philosophy is the knowledge, acquired by correct ratiocination, of properties of bodies from their conceived manners of generation, and again, of such manners of generation, as may be, from known properties.” This definition reappears almost literally in several of Hobbes’s other essays, for example in De Cive and in the Leviathan, and in a modified version in De Corpore. In the latter, he replaces “properties of bodies” by “effects or appearances” and “manners of generation” by “causes or manners of generation.” But one essential point remains unchanged: the second part of the definition is not a simple reversal of the first part, since Hobbes does not speak of “manners of generation” or of “causes,” but only of possible manners of generation or of possible causes. It is this second part of Hobbes’s theory that refers to natural philosophy. Hobbes stresses repeatedly that in the case of natural philosophy, causes can be concluded only from known effects. In contrast, in First Philosophy or geometry, conclusions can be drawn from known and true principles to their effects. According to Hobbes, this is the essential distinction of natural philosophy, which does not exist by accident. This essay explicates Hobbes’s argumentation for claiming this distinction for natural philosophy but not for geometry. In addition, the consequences of Hobbes’s methodological argument for natural philosophy are examined, especially the consequences for optics and astronomy. Finally, the question of whether there is a development in this theory will be explored. (shrink)

Gregorio Baldin’s book, La croisée des savoirs, concerns the intellectual relations among Hobbes, Mersenne, and Descartes. The study is limited to the time between 1634 and 1648, starting when Hobbes first met Mersenne in Paris and ending when Mersenne died. It covers three main topics. Part i is devoted to the relations maintained by Hobbes with the circle of Mersenne during 1634–1636, which Baldin thinks are essential for the development of Hobbes’ scientific thought. Part ii develops the theme of the (...) “hidden” influence of Mersenne on Hobbes’ thought, highlighting points of contact between the two authors, such as mechanism, research in optics, and their approach to epistemology. Part iii concerns Hobbes’ influence on Mersenne’s thought. It addresses several themes, starting with Mersenne’s interest in Hobbes’ system, the attitudes of Mersenne, Gassendi, and Hobbes toward Cartesian metaphysics, and ending with scientific themes debated in Mersenne’s circle during the 1640s. (shrink)

Descartes was disappointed with most of the Objections collected to accompany the Meditations in 1641, but he took a particularly dim view of the Third Set. ‘I am surprised that I have found not one valid argument in these objections,’ he wrote, close to the end of a series of curt and dismissive replies. The author of the objections was Thomas Hobbes. There was one other unfriendly exchange between Descartes and Hobbes in 1641. Descartes received through Mersenne some letters criticizing (...) theses in the Dioptrics, one of the Essays published with the Discourse on Method in 1637. Mersenne did not name Hobbes as the writer of the letters, attributing them to an unspecified Englishman, and it seems that Descartes never connected the critic of his optics with the author of the objections to his metaphysics. Nevertheless, Descartes responded with some hostility to the letters, angrily rebutting some points about refraction and charging that others had been appropriated from his own writings. Insinuating that the English correspondent was dishonest, Descartes decided to have no more to do with him. A meeting between the two men did take place in 1648 at a dinner given by the Marquis of Newcastle, but even on this occasion they did not see eye to eye, getting into an argument about the nature of hardness. (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)

The essay proposes to read the political science of Thomas Hobbes in the light of his studies on optics, with particular reference to De homine. I intend to verify the relationship existing in Hobbes's thought between the development of the theory of political representation and the subjective optical science, with particular reference to the theory of fiction.

Offers comprehensive treatment of Thomas Hobbes’s thought, providing readers with different ways of understanding Hobbes as a systematic philosopher As one of the founders of modern political philosophy, Thomas Hobbes is best known for his ideas regarding the nature of legitimate government and the necessity of society submitting to the absolute authority of sovereign power. Yet Hobbes produced a wide range of writings, from translations of texts by Homer and Thucydides, to interpretations of Biblical books, to works devoted to (...) geometry, optics, morality, and religion. Hobbes viewed himself as presenting a unified method for theoretical and practical science—an interconnected system of philosophy that provides many entry points into his thought. A Companion to Hobbes is an expertly curated collection of essays offering close textual engagement with the thought of Thomas Hobbes in his major works while probing his ideas regarding natural philosophy, mathematics, human nature, civil philosophy, religion, and more. The Companion discusses the ways in which scholars have tried to understand the unity and diversity of Hobbes’s philosophical system and examines the reception of the different parts of Hobbes’s philosophy by thinkers such as René Descartes, Margaret Cavendish, David Hume, and Immanuel Kant. Presenting a diversity of fresh perspectives by both emerging and established scholars, this volume: Provides a comprehensive treatment of Hobbes’s thought in his works, including Elements of Law, Elements of Philosophy, and Leviathan Explores the connecting points between Hobbes’ metaphysics, epistemology, mathematics, natural philosophy, morality, and civil philosophy Offers readers strategies for understanding how the parts of Hobbes’s philosophical system fit together Examines Hobbes’s philosophy of mathematics and his attempts to understand geometrical objects and definitions Considers Hobbes’s philosophy in contexts such as the natural state of humans, gender relations, and materialist worldviews Challenges conceptions of Hobbes’s moral theory and his views about the rights of sovereigns Part of the acclaimed Blackwell Companions to Philosophy series, A Companion to Hobbes is an invaluable resource for scholars and advanced students of Early modern thought, particularly those from disciplines such as History of Philosophy, Political Philosophy, Intellectual History, History of Politics, Political Theory, and English. (shrink)

At the beginning of the seventeenth century, the sine law of refraction had been discovered. Thus, natural philosophers tried even more to find a cause of refraction and to demonstrate the law. One of them was Thomas Hobbes, who was the author of the Leviathan and also worked on optics. At first, in the Hobbes analogy (1634), he was influenced by Ibn al-Haytham, just as Descartes was in his famous proof in the Dioptrique (1637). In his later optical scripts (...) Tractatus Opticus I (published 1644), Tractatus Opticus II (probably 1640), and A Minute or First Draught of the Optiques (1646), he developed a new explanation. Rejecting a corpuscular theory of light, Hobbes conceived a ray not as a body but as a motion originating from the light source: a ray can only be the motion of a body. The normal to the sides of a ray is called 'linea lucis'. If a ray is incident into another medium with a different density, one part of the linea lucis will be in the rarer and the other in the denser medium during an imperceptibly short period. Because the resistances in the two media are different, the parts of the linea lucis will move with different velocities; as a result the linea lucis will rotate and the direction of the ray will be changed. The next explanation given in De Corpore (1655) comes closer to the first one that Hobbes set down in the analogy. It must be asked why he replaced the theory of rotation by one which seems to carry less conviction. The reason could be that the dropped theory is founded in part on basic requirements of a corpuscular theory of light. Abandoning the whole theory might have been the lesser evil for Hobbes. In two later works, the Problemata Physica (1662) and the Decameron Physiologicum (1678), Hobbes varied his explanation without giving any proof for the sine law. It should be noted, however, that in the Decameron he refers to the proof contained in the Tractatus Opticus I, but not that given in De Corpore. (shrink)

At the beginning of the seventeenth century, the sine law of refraction had been discovered. Thus, natural philosophers tried even more to find a cause of refraction and to demonstrate the law. One of them was Thomas Hobbes, who was the author of the Leviathan and also worked on optics. At first, in the Hobbes analogy , he was influenced by Ibn al-Haytham, just as Descartes was in his famous proof in the Dioptrique . In his later optical scripts (...) Tractatus Opticus I , Tractatus Opticus II , and A Minute or First Draught of the Optiques , he developed a new explanation. Rejecting a corpuscular theory of light, Hobbes conceived a ray not as a body but as a motion originating from the light source: a ray can only be the motion of a body. The normal to the sides of a ray is called 'linea lucis'. If a ray is incident into another medium with a different density, one part of the linea lucis will be in the rarer and the other in the denser medium during an imperceptibly short period. Because the resistances in the two media are different, the parts of the linea lucis will move with different velocities; as a result the linea lucis will rotate and the direction of the ray will be changed. The next explanation given in De Corpore comes closer to the first one that Hobbes set down in the analogy. It must be asked why he replaced the theory of rotation by one which seems to carry less conviction. The reason could be that the dropped theory is founded in part on basic requirements of a corpuscular theory of light. Abandoning the whole theory might have been the lesser evil for Hobbes. In two later works, the Problemata Physica and the Decameron Physiologicum , Hobbes varied his explanation without giving any proof for the sine law. It should be noted, however, that in the Decameron he refers to the proof contained in the Tractatus Opticus I, but not that given in De Corpore. (shrink)

It was as a political thinker that Thomas Hobbes first came to prominence, and it is as a political theorist that he is most studied today. Yet the range of his writings extends well beyond morals and politics. Hobbes had distinctive views in metaphysics and epistemology, and wrote about such subjects as history, law, and religion. He also produced full-scale treatises in physics, optics, and geometry. All of these areas are covered in this Companion, most in considerable detail. The (...) volume also reflects the multidisciplinary nature of current Hobbes scholarship by drawing together perspectives that are now being developed in parallel by philosophers, historians of science and mathematics, intellectual historians, political scientists, and literary theorists. (shrink)

The nature of light is a focus of Thomas Hobbes’s natural philosophical project. Hobbes’s explanation of the light of lucid bodies differs across his works, from dilation and contraction in Elements of Law to simple circular motions in De corpore. However, Hobbes consistently explains perceived light by positing that bodily resistance generates the phantasm of light. In Letters I.XIX–XX of Philosophical Letters, fellow materialist Margaret Cavendish attacks the Hobbesian understanding of both lux and lumen by claiming that Hobbes (...) has illicitly made abstractions from matter. In this paper, I argue that Cavendish’s criticisms rely on an incorrect understanding of the nature of Hobbesian geometry and the role it plays in Hobbes’s natural philosophy. Rather than understanding geometry as wholly abstract, Hobbes attempts to ground geometry in different ways of considering bodies and their motions. Furthermore, Hobbes’s own criticisms of abstraction suggest that he would share many of the worries she raises but deny that he falls prey to them. (shrink)

v. 1. Editorial introduction -- v. 2. The English and Latin texts (i) -- v. 3. The English and Latin texts (ii).

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)

Unlike some other reproductions of classic texts (1) We have not used OCR(Optical Character Recognition), as this leads to bad quality books with introduced typos. (2) In books where there are images such as portraits, maps, sketches etc We have endeavoured to keep the quality of these images, so they represent accurately the original artefact. Although occasionally there may be certain imperfections with these old texts, we feel they deserve to be made available for future generations to enjoy.

Thomas Hobbes' timeless account of the human condition, first developed in The Elements of Law (1640), which comprises Human Nature and De Corpore Politico, is a direct product of the intellectual and political strife of the seventeenth century. His analysis of the war between the individual and the group lays out the essential strands of his moral and political philosophy later made famous in Leviathan. This first ever complete paperback edition of Human Nature and De Corpore Politico is also supplemented (...) by chapters from Hobbes' later work De Corpore and "The Three Lives," never before published together in English. (shrink)

For the first time in three centuries, this book brings back into print three discourses now confirmed to have been written by the young Thomas Hobbes. Their contents may well lead to a resolution of the long-standing controversy surrounding Hobbes's early influences and the subsequent development of his thought. The volume begins with the recent history of the discourses, first published as part of the anonymous seventeenth-century work, Horae Subsecivae . Drawing upon both internal evidence and external confirmation afforded by (...) new statistical "wordprinting" techniques, the editors present a compelling case for Hobbes's authorship. Saxonhouse and Reynolds present the complete texts of the discourse with full annotations and modernized spellings. These are followed by a lengthy essay analyzing the pieces' significance for Hobbes's intellectual development and modern political thought more generally. The discourses provide the strongest evidence to date for the profound influences of Bacon and Machiavelli on the young Hobbes, and they add a new dimension to the much-debated impact of the scientific method on his thought. The book also contains both introductory and in-depth explanations of statistical "wordprinting.". (shrink)

Thomas Hobbes took a new look at the ways in which society should function, and he ended up formulating the concept of political science. His crowning achievement, Leviathan, remains among the greatest works in the history of ideas. Written during a moment in English history when the political and social structures as well as methods of science were in flux and open to interpretation, Leviathan played an essential role in the development of the modern world. This edition of Hobbes' landmark (...) work is based on the original text. It incorporates the author's own corrections and retains the period spelling and punctuation, offering both flavorful authenticity and the utmost clarity of expression. (shrink)

A cornerstone of modern western philosophy, addressing the role of man in government, society and religion In 1651, Hobbes published his work about the relationship between the government and the individual. More than four centuries old, this brilliant yet ruthless book analyzes not only the bases of government but also physical nature and the roles of man. Comparable to Plato's Republic in depth and insight, Leviathan includes two society-changing phenomena that Plato didn't dare to dream of -- the rise of (...) great nation-states with their claims to absolute sovereignty, and modern science, with its unprecedented analytic power. To Hobbes, the leviathan -- a mythical sea creature described in the Old Testament -- represented his central thesis: that the state must be strong in order to control and protect its citizens. Even today, Hobbes's thesis in Leviathan is debated among scholars and philosophy aficionados around the globe. One of the earliest attempts at a genuinely scientific understanding of politics and society in their modern form, this book also remains one of the most stimulating. In his timeless work, Hobbes outlines his ideas about the passions and the conduct of man, and how his theories are realized in every individual. Addressing free will and religion, Hobbes constructs an intelligent argument for the basis of religion within government and how to organize a peaceful and successful Christian commonwealth. Like Plato's Republic, this book contains ideas on psychology, ethics, law, language, and religion that continue to challenge modern thinkers and exercise a profound influence on Western thought. A classic treatise of philosophy, Leviathan is critical reading for anyone who wishes to examine the human mind through the prisms of government and society. (shrink)

This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be (...) preserved, reproduced, and made generally available to the public. To ensure a quality reading experience, this work has been proofread and republished using a format that seamlessly blends the original graphical elements with text in an easy-to-read typeface. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant. (shrink)

De Cive (On the Citizen) is the first full exposition of the political thought of Thomas Hobbes, the greatest English political philosopher of all time. Professors Tuck and Silverthorne have undertaken the first complete translation since 1651, a rendition long thought (in error) to be at least sanctioned by Hobbes himself. On the Citizen is written in a clear, straightforward, expository style, and in many ways offers students a more digestible account of Hobbes's political thought than the Leviathan itself. This (...) new translation is both accurate and accessible, and is itself a significant scholarly event: it is accompanied by a full glossary of Latin terms, a chronology, bibliography, and an expository introduction. Throughout the editors have emphasised consistency in the translation and usage of Hobbes's basic conceptual vocabulary, respecting Hobbes's own concern for accurate definition of terms. (shrink)

De Cive ("On the citizen") is one of Thomas Hobbes's major works. "The book was published originally in Latin from Paris in 1642, followed by two further Latin editions in 1647 from Amsterdam. The English translation of the work made its first appearance four years later (London 1651) under the title 'Philosophicall rudiments concerning government and society'."The work anticipates themes of the better-known Leviathan. The famous phrase bellum omnium contra omnes ("war of all against all") appeared first in De Cive.

Thomas Hobbes (1588-1679) was an English philosopher, remembered today for his work on political philosophy. His 1651 book Leviathan established the foundation for most of Western political philosophy from the perspective of social contract theory. He also contributed to a diverse array of fields, including history, geometry, physics of gases, theology, ethics, general philosophy, and political science. He was one of the main philosophers who founded materialism. He visited Florence in 1636 and later was a regular debater in philosophic groups (...) in Paris, held together by Marin Mersenne. Hobbes's first area of study was an interest in the physical doctrine of motion and physical momentum. Despite his interest in this phenomenon, he disdained experimental work as in physics. He built a good reputation in philosophic circles and in 1645, he was chosen with Descartes, Gilles de Roberval and others, to referee the controversy between John Pell and Longomontanus over the problem of squaring the circle. His other works include: The Elements of Law Natural and Politic (1640) and De Cive (The Citizen): Philosophical Rudiments Concerning Government and Society (1651). (shrink)

Coherence in conversations and in texts can be partially characterized by a set of coherence relations, motivated ultimately by the speaker's or writer's need to be understood. In this paper, formal definitions are given for several coherence relations, based on the operations of an inference system; that is, the relations between successive portions of a discourse are characterized in terms of the inferences that can be drawn from each. In analyzing a discourse, it is frequently the case that we would (...) recognize it as coherent, in that it would satisfy the formal definition of some coherence relation, if only we could assume certain noun phrases to be coreferential. In such cases, we will simply assume the identity of the entities referred to, in what might be called a “petty conversational implicature,” thereby solving the coherence and coreference problems simultaneously. Three examples of different kinds of reference problems are presented. In each, it is shown how the coherence of the discourse can be recognized, and how the reference problems are solved, almost as a by‐product, by means of these petty conversational implicatures. (shrink)