Dominique Raynaud

Unlike the physical sciences, sociology is frequently described as an interpretative non-experimental science. Comparative epistemology sheds new light on this claim. 1. Experimentation is not a constant character of the physical sciences; 2. Experimental hypothetical-deductive reasoning, including the test of predictions, is also practicable in sociology. The argument is developed by a detailed step-wise comparison of the prediction of light ray deviation within the Sun’s gravitational field made in 1919 (physics) and the prediction of 8% cosmopolitanism of Cambridge University between 1250 and 1350 (sociology). Extensive analysis of regent masters’ prosopographic notes yields the result of 9.5 percent cosmopolitanism, which is close to the theoretical prediction. Au contraire des sciences physiques, la sociologie est souvent décrite comme une science interprétative et non-expérimentale. L’épistémologie apporte un éclairage nouveau sur cette position : 1) L’expérimentation n’est pas un trait constant des sciences physiques ; 2) Le raisonnement expérimental est également applicable en sociologie. L’argument est développé en comparant en détail le test de la prédiction d’une déviation des rayons lumineux dans un champ de gravitation effectué en 1919 et le test de la prédiction d’un taux de cosmopolitisme de 8 % de l’université de Cambridge dans la période 1250-1350. Le dépouillement des notices prosopographiques des maîtres régents donne un résultat de 9,5 % proche de la prédiction théorique initiale.

Est-il vrai que la science et la technologie forment un tout ? Qu’elles sont unies par des liens constants et nécessaires ? Est-il vrai que le raisonnement technologique prend toujours place dans un contexte industriel ? Que les bio- et nanotechnologies forment la part essentielle des technologies contemporaines ? Que l’application définit adéquatement la relation entre la science et la technologie ? Dans ce livre, Dominique Raynaud examine les limites de chacune de ces idées. Il dresse un panorama complet des problèmes que pose la technologie au moyen d’une étude détaillée des aspects cognitifs, ergologiques, professionnels et juridiques de la relation entre la science et la technologie et met à nu la fiction utilitariste de la prétendue « technoscience ». Tout aussi éloigné de l’apologie que de la critique radicale, ce livre défend une perspective empirique et analytique dans l’étude de la technologie.

The concept of aerial perspective has been used for the first time by Leonardo da Vinci (1452-1519). This article studies its dependence on Ptolemy’s Optica and overall on the optical tradition inaugurated by Ibn al-Haytham’s Kitāb al-Manāẓir (d. after 1040). This treatise, that was accessible through several Latin and Italian manuscripts, and was the source of many Medieval commentaries, offers a general theory of visual perception emancipated from the case of the moon illusion, in which physical and psychological factors are closely combined. Atmospheric extinction (not refraction, which it is sometimes confused with) affects the conjectured size of remote objects. This phenomenon is also the core source for a pictorial rendering of depth, that is based onto a principle different from the diminution of size.

The modern physiological optics introduces the notions related to the conditions of fusion of binocular images by the concept of correspondence, due to Christiaan Huygens, and by an experiment attributed to Christoph Scheiner. The conceptualization of this experiment dates, in fact, back to Ptolemy and Ibn al-Haytham. The present paper surveys Ibn al-Haytham's knowledge about the mechanisms of binocular vision. The article subsequently explains why Ibn al-Haytham, a mathematician, but here an experimenter, did not give the circular figure of the theoretical horopter, construction due to Gerhard Vieth and Johannes Müller. But, on the other hand, it is clear that Ibn al-Haytham's experimental study puts in place the notion of corresponding points, the cases of homonymous and cross diplopia, and even prepares the discovery of Panum area.

This book provides the first critical edition of Ibn al-Haytham’s On the Shape of the Eclipse with English translation and commentary, which records the first scientific analysis of the camera obscura. On the Shape of the Eclipse includes pioneering research on the conditions of formation of the image, in a time deemed to be committed to aniconism. It also provides an early attempt to merge the two branches of Ancient optics—the theory of light and theory of vision. What perhaps most strongly characterizes this treatise is the close interaction of a geometric analysis of light and experimental reasoning. Ibn al-Haytham conducted his experiments in a systematic way by varying all that could be changed: the shape and size of the aperture, the focal length of the camera obscura, the distance and shape of the celestial bodies. This way, he achieved a thorough understanding. This work represents a decisive step in both the history of optics and the application of the experimental method that was just as efficient in medieval Islam as today.

Leonardo’s research on the eye and vision has given rise to contrasting assessments, ranging from the apology of his explanation of how the eye works as a camera obscura to the most critical attitude. The negative judgments derive some of their strength from the fact that the practice of anatomy and linear perspective are well documented in Leonardo. Thus one expects him to have had empirically based knowledge of the organs dissected, as well as comprehensive skills in optics. As we will see, none of these ideas is entirely right.

"Toute forme a été imaginée avant d'être construite". Cette formule classique, qui met en relief l'un des traits essentiels de la pratique architecturale, soulève plusieurs questions. D'où viennent les images-mères du projet? Sont-elles encore identifiables une fois construites? Existe-t-il des procédés réguliers dans l'imagination des formes architecturales? Cette enquête tente de résoudre ces problèmes par la reconnaissance de schèmes dynamiques de l'imagination. Si le processus de conception architecturale altère les images-mères au points que certains ont pu identifier une "non figurativité" de l'architecture, les schèmes dynamiques sont perceptibles de la première esquisse à l'édifice construit. La démonstration, au croisement de l'anthropologie des représentations et de l'architecturologie, adopte le principe d'une analyse comparée. Etayée par une sélection d'édifices couvrant toute l'extension historique et géographique, elle offre tout à la fois une lecture cohérente des premiers moments du projet architectural et une réflexion de portée générale sur l'imagination des formes.

The perfect compass, used by al-Qūhī, al-Sijzī and his successors for the continuous drawing of conic sections, reappeared after a long eclipse in the works of Renaissance mathematicians like Francesco Barozzi in Venice. The resurgence of this instrument seems to have depended on its interest to solve new optico-perspective problems. Having reviewed the various instruments designed for the drawing of conic sections, the article is focused on the sole conic compass. Theoretical and empirical applications are detailed. Contrarily to the common thesis of an independant discovery, various elements suggest a direct descent between the birkār al-tāmm of the Arabic mathematical tradition and the Italian conic compass. Then we present the most probable transmission hypothesis involving: 1° Ibn Yūnus and his disciples of Mosul, 2° Sultan Malik al-Kāmil in Damas, 3° Master Theodore and Frederick II at the court of Sicily, 4° Andalò di Negro and Robert of Anjou in Naples, 5° Lorenzo della Volpaia, Vinci, Sangallo and Michelangelo in Florence, 6° Ausonio, Contarini, Thiene and Francesco Barozzi in Venice.

This article aims at contributing to the methods of the sociology of science, from an empirical study of the determinations of the velocity of light between 1676 and 1983. Far from being constructed and deconstructed at pleasure, the values of c have undergone a tendentially unidirectional and irreversible process of revision. The competing methods remained in the running as long as they produced an uncertainty less than, or equal to, the best known value. The analysis of “entrances” and “exits” of the methods on the research front makes clear the nature of scientific competition, which is a form of “redistributive emulation” that owes nothing to political rivalry or economic competition. By achieving results that differ from constructivism on the themes of literary inscription, games of construction/deconstruction, negotiation, and persuasion, this article outlines a kind of internalist sociology of science, which aims at exploring all aspects that make science science.

In Scientific Controversies, Dominique Raynaud shows how organized debates in the sciences help us establish or verify our knowledge of the world. If debates focus on form, scientific controversies are akin to public debates that can be understood within the framework of theories of conflict. If they focus on content, then such controversies have to do with a specific activity and address the nature of science itself. Understanding the major focus of a scientific controversy is a first step toward understanding these debates and assessing their merits. Controversies of unique socio-historic context, disciplines, and characteristics are examined: Pasteur’s germ theory and Pouchet’s theory of spontaneous generation; vitalism advocated at Montpellier versus experimental medicine in Paris; the science of optics about the propagation of visual rays; the origins of relativism (the Duhem-Quine problem). Touching on the work of Boudon, Popper, and others, Raynaud puts forward an incrementalist theory about the advancement of science through scientific controversies. The debates Raynaud has selected share in common their pivotal importance to the history of the sciences. By understanding the role of controversy, we better understand the functioning of science and the stakes of the contemporary scientific debates.

Définir, à partir des traces graphiques d'un projet, les actions de conception et les motivations de l'architecte à les entreprendre, voilà l'objectif de l'enquête. Quel est le rôle de la représentation dans le développement de l'idée architecturale? Comment se transforme-t-elle tout au long du projet? En fonction de quoi l'architecte décide-t-il d'altérer ou de maintenir une représentation? Telles sont les questions que ces essais tentent de résoudre en s'appuyant sur les concepts de représentation, d'inférence, de modèle et d'échelle, et en portant une attention particulière au rôle que jouent les schèmes dans la conception architecturale. Les conclusions sont tirées d'études de cas qui portent sur des projets de l'Atelier Zô, Scarpa, Le Corbusier, Pei.

The modern physiological optics introduces the notions related to the conditions of fusion of bi- nocular images by the concept of correspondence, due to Christiaan Huygens (1704), and by an experiment attri- buted to Christoph Scheiner (1619). The conceptualization of this experiment dates, in fact, back to Ptolemy (90- 168) and Ibn al-Haytham (d. af. 1040). The present paper surveys Ibn al-Haytham's knowledge about the mecha- nisms of binocular vision. The article subsequently explains why Ibn al-Haytham, a mathematician, but here an experimenter, did not give the circular figure of the theoretical horopter, construction due to Gerhard Vieth (1818) and Johannes Müller (1826). But, on the other hand, it is clear that Ibn al-Haytham's experimental study puts in place the notion of corresponding points, the cases of homonymous and cross diplopia, and even prepares the discovery of Panum area. L'optique physiologique moderne introduit les notions relatives aux conditions de fusion des images binoculaires par le concept de correspondance, prêté à Christiaan Huygens (1704), et par une expérience attribuée à Christoph Scheiner (1619). L'article montre que la conceptualisation de l'expérience remonte en fait à Ptolémée (90-168) et à Ibn al-Haytham (m. ap. 1040), et précise les connaissances que ce dernier avait des mécanismes de la vision binoculaire. Il est ensuite expliqué pourquoi Ibn al-Haytham, mathématicien mais ici expérimentateur, ne donne pas la forme circulaire de l'horoptère théorique, dont la construction revient à Gerhard Vieth (1818) et Johannes Müller (1826). En revanche, l'étude expérimentale d'Ibn al-Haytham met en place la notion de points correspondants, les cas de diplopie homonyme et croisée et prépare même la découverte de l'aire fusionnelle de Panum

The controversy between the medical schools of Paris and Montpellier extends roughly from the death of Barthez (1806) to the publication of the Introduction to the study of experimental medicine of Claude Bernard (1865), with a peak during which the controversy merges with the polemic between Louis Peisse and Jacques Lordat (1840-1843). This study aims to document as accurately as possible the arguments that were exchanged during this controversy, by seeking their reasons and explaining how the experimental medicine in Paris ultimately took the lead over the vitalism championed by the school of medicine in Montpellier.

Ce livre souhaite montrer, par une comparaison des concepts et des méthodes de la sociologie avec ceux des sciences naturelles, que beaucoup des critères avancés pour doter la sociologie d’un statut épistémologique spécial — et, pour tout dire, souvent dérogatoire — ont un caractère douteux. Éléments d’un discours identitaire partiellement dérivés du Methodenstreit allemand, ces critères — réalisme des théories sociologiques, multiplicité et irréductibilité des paradigmes sociologiques, langage, concepts et programmes inclarifiables, statut logique hors norme des concepts sociologiques, historicité des faits sociaux, inexistence de lois, impossibilité du raisonnement expérimental — ne résistent pas à l’examen critique. Par bien des aspects, la sociologie apparaît être une science ordinaire, ni mieux, ni plus mal lotie que les autres.

This article aims to test a new method of dating optico-astronomical manuscripts, using Ibn al-Haytham’s Epistle on the Shape of the Eclipse as the test case. This work is selected because of indications that its diagrams are based on reality. After clarifying the observation conditions, an astronomical ephemeris is applied to sift through the eclipses that occurred during Ibn al-Haytham’s life throughout the area he is believed to have sojourned. Next, the remaining eclipses are sorted by computing the image projection. The results show that Ibn al-Haytham’s Epistle is likely to have reported the partial solar eclipse of 28 Rajab A.H. 380/21 October 990 in Baṣra. Because this exercise is primarily the test of a new method, this finding should be regarded as a tentative outcome, pending further information.

Brisant l’image idéale de la science consensuelle, les controverses scientifiques sont aujourd’hui devenues un sujet privilégié de la sociologie et de l’histoire des sciences. Elles sont par ailleurs impliquées au cœur des débats sur les méthodes des sciences sociales. Si l’analyse des controverses scientifiques doit beaucoup aux approches inaugurées par les courants relativistes et constructivistes des années 1970-1980, ce livre montre que les études contemporaines ont tout à gagner à réintroduire ce qui a été le principal tabou des trente dernières années: la vérité. Cette conclusion n’est pas le résultat d’une méditation abstraite sur le destin de la sociologie et de l’histoire des sciences. C’est le résultat d’études de cas, portant sur des disciplines telles que la biologie (la thèse des générations spontanées, débattue entre Pasteur et Pouchet), de la médecine (le vitalisme opposé à la médecine expérimentale naissante), de la stéréotomie (les « Guerres perspectives » qui ont agité le Paris des années 1640), de la perspective (la mathématisation de la perspective dans l’Italie du 16e siècle) ou de l’optique (la question de l’intromission, discutée à Oxford). De querelles médiévales à des disputes plus récentes, ces études suivent un même fil conducteur : interroger les rôles de la rationalité, des conventions et des croyances collectives dans la construction des théories scientifiques. L’auteur défend une théorie incrémentaliste du progrès scientifique: pour autant qu’il suive des règles, le débat est un moyen pratique de tester la robustesse d’une théorie et de départager les théories rivales. Le fait que les débats soient souvent marqués par la passion et les émotions est sans intérêt ; l’important est que ces échanges réglés puissent, par la production d’arguments publics, s’approcher de la vérité. C’est une façon de répondre à la question : Pourquoi l’activité scientifique est-elle conflictuelle?

This article studies a fragment on the conic sections that appear in the Codex Atlanticus, fols. 611rb/915ra. Arguments are put forward to assemble these two folios. Their comparison with the Latin texts available before 1500 shows that they derive from the De speculis comburentibus of Alhacen and the De speculis comburentibus of Regiomontanus, joined together in his autograph manuscript. Having identified the sources, and discussed their mathematics, the issue of their transmission is targeted. It is shown that these notes were written by Paolo dal Pozzo Toscanelli, through whom they reached the notebooks of Leonardo da Vinci.

This paper wonders why the Franciscan order took part in the diffusion of optics more than other medieval organisation, both religious and secular. First, clues of this social asymmetry are given. Then, an explanation is put forward: 1. An initial asymmetry existed, by the fact that Grosseteste’s optics was known in the Franciscan studium of Oxford; 2. Since that date, optics spread among the order by a network effect; 3. The rivaltry between the mendicant orders and the homophilia that presided over their conventual libraries’ purchasing policy finally explains why other contemporary organizations, similarly structured, took a smaller interest into optics. In spite of an evident topical connection, this explanation deeply differs from the analysis that has been applied to the Puritans’ and Jesuits’ scientific activity in XVIIth and XVIIIth centuries classical Europe. It does not appeal to the heavy hypothesis of ethos in order to understand scientific development.

Le regain actuel de la sociologie de l'art semble lié à un essai de constitution d'un programme de 'sociologie des œuvres', différencié de la classique sociologie de la production et de la réception artistiques. Ce programme, épigone des théories de la communication, fait l'hypothèse de codes iconiques et plastiques. L'étude des interprétations des rayures de D. Buren et de la pyramide du Grand Louvre de I. M. Pei invalide l'existence de tels codes. La grande variabilité des interprétations est alors expliquée dans le cadre du modèle inférentiel avancé par Sperber et Wilson (1989). L'absence de code et le caractère auto-réfutant de certaines propositions met en doute les chances de succès de ce programme de recherche

In the Quattrocento and Cinquecento the rise of linear perspective caused many polemics which opposed the supporters of an artificial geometrisation of sight to those who were praising the qualities of the drawing according to nature, or were invoking some arguments on a physiological basis. These debates can be grouped according to the four alternatives that form their central concerns: restricted vs. broad field of vision; ocular immobility vs. mobility; curvilinear vs. planar picture; monocular vs. binocular vision. By retaining the first terms of these four alternatives, the history of perspective eliminated many heterodox constructions. From the viewpoint of mathematisation the interest of these debates is that they succeeded, rather than preceded, the adoption of a perspective system defined by the intersection of the visual pyramid. Thus the history of linear perspective constitutes a genuine case of a posteriori justification, or, put differently, it gives us a case of upside down mathematisation.