Although Aristotle’s Metaphysics received much attention in the nineteenth and the twentieth centuries, scholars and historians of science were not particularly interested in clarifying the aim of Aristotle’s appeal to astronomy in Λ 8. Read with monotheistic prejudices, this chapter was quickly abandoned by Aristotelian scholars as a gratuitous insertion, which downgrades Aristotle’s God for the sake of some supplementary principles, whose existence was dictated by celestial mechanics. On the other hand, historians of astronomy read the astronomical excursus as providing (...) a picture of Aristotle as an able astronomer, who made an important contribution to the theory of concentric celestial spheres of Eudoxus and Callippus by adding the counteracting spheres. The present article argues (a) that Aristotle purposefully turned to astronomy as the only mathematical science whose objects were correlative to the immaterial first substances or gods, the number of which had to be precisely determined by his own project of first philosophy; and (b) that he had no aspiration of improving the astronomical theory of his peers, contrary to an interpretation that first emerged with the Peripatetic exegete Sosigenes in the second century A.D. (shrink)

This chapter contains sections titled: Introduction The Stoic Logical System Conclusion Bibliography.

It is argued that according to Aristotle the universe is a single substance with its own form and matter.

In his commentary on Physics I 9, Simplicius claims that individual forms individuate matter. Given that in the same text he calls the immanent form ‘universal,’ it seems reasonable to conclude that the individual forms are individual instances of one universal species–form. However, Simplicius also mentions accidental properties that are peculiar to form rather than to matter. On the basis of Simplicius’ commentaries on the Categories and on the Physics, I argue that the individuating accidents are not part of the (...) individual forms, but that each individual’s form coordinates the individual’s accidental features. By belonging to a certain species, the individual form sets limits as to which accidents a matter–form compound can assume. This approach enables Simplicius to combine hylomorphism with a theory of individuation through properties. Furthermore, in his commentary on De Caelo I 9 Simplicius explains the uniqueness of each individual’s conglomeration of properties in light of his Neoplatonic cosmology: each individual corresponds to an individual cosmic disposition that determines its characteristic features. (shrink)

ArgumentThe present paper is an attempt to understand how medieval astronomers working within the Ptolemaic astronomical context in which the annular eclipse is an unjustified and impossible phenomenon, could know, define, justify, and later make attempts that led to success in predicting annular solar eclipses. As a context-based study, it reviews the situation of annular eclipses with regard to the medieval hypotheses applied to the calculation of the angular diameters of the sun and the moon, which was basic for contemplating (...) the possibility of annular eclipses. This gives the premises and the preliminary insights that were necessary to clarify the complex situation of the annular eclipse in the late medieval Islamic period and to explain the historical mechanisms leading to justifying the phenomenon during that period. This was, first due to a convincing and efficient observational evidence which, of course, was available only to a number of medieval astronomers and significantly for only a limited time period, and, second, the result of an amazing interaction amongst various astronomical traditions available to them. At a more general level, the research aims to inspect or, at least, to give some impressions of the essential conditions, i.e., identification of phenomenon, empirical evidence, and the justifying underlying tradition, under which it became possible in the tradition-based science of the `medieval period to permit a not-already-defined and tradition-opposed phenomenon to be posed and justified. (shrink)

This paper examines geometrical arguments from Galileo's Mechanics and Two New Sciences to discern the influence of the Aristotelian Mechanical Problems on Galileo's dynamics. A common scientific procedure is found in the Aristotelian author's treatment of the balance and lever and in Galileo's rules concerning motion along inclined planes. This scientific procedure is understood as a development of Eudoxan proportional reasoning, as it was used in Eudoxan astronomy rather than simply as it appears in Euclid's Elements. Topics treated include the (...) significance of the circle in Galileo's demonstrations, the substitution of rectilinear elements for heterogeneous factors like weight and curvilinear distance, and the way in which elements of a motion are used to measure other elements of the same motion. The indirectness of Galileo's proofs, his conception of speed as relative and comparative, and the meaning of his concept of moment all come into clearer focus. Conclusions are drawn about Galilean idealization, and also about the contrast of literal versus figural modes of explanation in Galileo's science. (shrink)

Dans son Traité 29, « Sur la vision », Plotin aborde à ce propos une difficulté consistant à savoir quelle part y joue le « milieu » séparant l’objet senti de l’organe. Cette question occupe les quatre premiers chapitres du traité : afin d’y préciser le rôle du milieu dans la perception visuelle, Plotin en admet provi­soirement la nécessité, dressant au premier chapitre la liste des possibilités théo­riques envisageables à partir de cette hypothèse de travail. Afin de mieux voir les (...) étapes et les enjeux de cette argumentation dense, elliptique et à peine effleurée par les études sur la question, je l’analyse ici à la lumière de textes antérieurs por­tant sur les modalités de la sensation comme telle et sur le problème, plus géné­ral, de la transmission d’une affection à travers un milieu donné. Ces questions, abordées avant Plotin dans des cadres divers et à partir de problématiques va­riant d’un auteur à l’autre (Platon, Aristote et ses successeurs dans le Lycée, Chrysippe de Soles, Plutarque de Chéronée, Pline l’Ancien, Galien de Pergame), ont été retravaillées par Alexandre d’Aphrodise à propos d’un thème précis, pour donner lieu à un modèle original de transmission dont j’aimerais montrer qu’il est d’un apport décisif dans le Traité 29, puisqu’il donne à Plotin l’instru­ment indispensable pour, en l’approfondissant afin de mieux le dépasser, élabo­rer par là sa propre théorie de la vision, solidaire d’un processus de désaffection du milieu perceptif amorcé avant lui. (shrink)

It is well known that heliocentrism was proposed in ancient times, at least by Aristarchus of Samos. Given that ancient astronomers were perfectly capable of understanding the great advantages of heliocentrism over geocentrism—i.e., to offer a non-ad hoc explanation of the retrograde motion of the planets and to order unequivocally all the planets while even allowing one to know their relative distances—it seems difficult to explain why heliocentrism did not triumph over geocentrism or even compete significantly with it before Copernicus. (...) Usually, scholars refer to explanations of sociological character. In this paper, I offer a different explanation: that the pre-Copernican heliocentrism was essentially different from the Copernican heliocentrism, in such a way that the adduced advantages of heliocentrism can only be attributed to Copernican heliocentrism, but not to pre-Copernican heliocentrism proposals. (shrink)

: In earlier work, Bernard R. Goldstein and the present author have introduced a procedural rule for historical inquiry, which requires that one take pains to establish the credibility of any citation of ancient thought by later writers in antiquity through a process of verification. In this paper, I shall apply what I call the Rule of Ancient Citations to Simplicius' interpretation of Aristotle's remarks in Meta L. 8, which is the primary point of departure for the modern understanding of (...) Greek planetary theory. I first sketch several lines of argument that lead me to conclude that Simplicius' interpretation should not be accepted because it assumes a concern with planetary phenomena unknown to the Greeks before the late 2nd and early 1st centuries BC. Then, after showing that there is a fairly well defined range of readings of Aristotle's remarks more in keeping with what we actually know of astronomy in the 5th and 4th centuries BC, I conclude that neither Aristotle's report about the Eudoxan and Callippan accounts of the celestial motions nor Simplicius' interpretation of this report is a good starting point for our understanding of early Greek planetary theory. (shrink)

L’article met en lumière la continuité intellectuelle de l’Académie à propos d’une question précise, les rapports entre philosophie et géométrie. On soutient d’abord que, dans les livres VI-VII de la République, Platon ne cherche pas à réformer les pratiques des géomètres mais identifie les contraintes incontournables de leurs raisonnements (constructions, hypothèses), qui constituent et limitent leur objectivité. On montre ensuite que cette analyse constitue le cadre des réflexions académiciennes ultérieures sur la géométrie. Speusippe reprend et développe l’analyse platonicienne des constructions (...) géométriques, qui est appliquée (de Speusippe à Crantor) à la cosmologie et même à la doctrine des principes, afin d’expliquer comment elles saisissent leurs objets éternels depuis le devenir, de manière indirecte. Si la Nouvelle Académie d’Arcésilas et de Carnéade critique les mathématiques, on fait l’hypothèse qu’il s’agissait pour elle – dans le contexte des débats philosophiques hellénistiques sur les usages des mathématiques –, de rappeler les limites de leur objectivité contre toute idéalisation dogmatique de la méthode géométrique. (shrink)

Il est relativement peu de textes qui, dans le De Cœlo, témoignent de l’existence de réalités incorporelles transcendantes à l’ordre astral. La conclusion, sur laquelle se referme la démonstration de l’unicité du ciel en I 9, est-elle de ceux‑là? Les « êtres de là-bas » y désignent-ils les réalités sidérales les plus hautes ou certaines instances hypercosmiques? C’est à l’identification de ces êtres qu’il s’agit ici de procéder. En montrant que convergent ensemble les indices textuels du passage et son homogénéité (...) démonstrative, il pourra alors apparaître que ces êtres, dont Aristote vante l’immutabilité et la perfection, transcendent l’ordre céleste, sans qu’on puisse toutefois déterminer la relation exacte qui les unit au ciel, obérant ainsi la possibilité de lire, à travers eux, une référence implicite à la doctrine du Premier Moteur Immobile. (shrink)