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 idea that linear perspective arose only in the West due to the strength of an unusual process of rationalization is denied by the fact that IXth century Islamic scholars had yet a thorough knowledge of the optical and geometrical materials required in perspective. In addition, the process of rationalization was rarely so intense as in that time, because truth uniqueness and scientific communalism were core values of Medieval Islam. The puzzle is not a matter of less or more rationality, but a matter of axiological motives. First, Islamic disregard for perspective is the result of a value-set insofar painters were fearing the hadīths' prohibition, or wished to avoid pretentiousness of their name (muṣawwir). Second, Islamic art did not draw from Qurʿān and hadīth's precepts directly. Third, painters implemented axiological motives, to put iconic practice in accordance with aniconic leanings.

L'étude de la conception architecturale se trouve au carrefour de trois approches: sciences de la conception, psychologie cognitive et architecturologie. Cette dernière tente de modéliser toute la gamme des changements d'état qui apparaissent durant le processus de conception. L'architecturologie sait décrire, au moyen d'échelles, les opérations de conception par lesquelles l'architecte attribue des mesures à l'édifice. Cette modélisation paraît adéquate lorsque le modèle morphologique n'est pas transformé durant le processus de conception (comme dans certains projets de Jørn Utzon ou de Alvar Aalto). Dans d'autres cas – comme dans certains projets de Philibert de l'Orme, Ludwig Mies van der Rohe, Norman Foster – les changements d'état altèrent la structure même du modèle morphologique. De telles transformations ne peuvent plus être décrites par l'échelle. Reprenant une idée de Herbert A. Simon, l'article suggère que la description de ces nouvelles transformations appelle une autre classe d'opérateurs. Ce pourrait être des schèmes, si l'on entend par ce terme la classe des actions prototypiques qui peuvent être exprimées par des verbes fondamentaux comme ouvrir, fermer, séparer, lier, etc.

This article studies the legacy in the West of Abū al-Wafā’s Book on those Geometric Constructions which are Necessary for Craftsmen. Although two-thirds of the geometric constructions in the text also appear in Renaissance works, a joint analysis of original solutions, diagram lettering and probability leads to a robust finding of independent discovery. The analysis shows that there is little chance that the similarities between the contents of Abū al-Wafā’s Book and the works of Tartaglia, Marolois and Schwenter owe anything to historical transmission. The commentary written by Kamāl al-Dīn Ibn Yūnus seems to have had no Latin legacy either.

L'essor de la perspective linéaire a suscité de nombreuses polémiques tout au long du Quattrocento et du Cinquecento, opposant les partisans d'une géométrisation artificialiste de la vision à ceux qui vantaient les qualités du dessin d'après nature ou invoquaient des arguments de nature physiologique. Ces débats peuvent être retracés à partir des quatre alternatives qui en constituent le noyau dur : champ de vision restreint vs. large ; immobilité vs. mobilité oculaire ; tableau plan vs. curviligne ; vision monoculaire vs. binoculaire. En retenant les premiers termes de ces quatre alternatives, l'histoire de la perspective a rejeté de nombreux systèmes hétérodoxes. Du point de vue de la mathématisation, l'intérêt de ces débats tient à ce qu'ils ont succédé, et non précédé, l'adoption du dispositif perspectif comme intersection de la pyramide visuelle. L'histoire de la perspective linéaire offre ainsi un authentique cas de justification a posteriori des fondements ou, pour ainsi dire, de mathématisation à rebours

Contemporary sociology of scientific knowledge (SSK) is defined by its relativist trend. Its programme often calls for the support of philosophers, such as Duhem, Quine, and Wittgenstein. A critical re-reading of key texts shows that the main principles of relativism are only derivable with difficulty. The thesis of the underdetermination of theory doesn't forbid that Duhem, in many places, validates a correspondence-consistency theory of truth. He never said that social beliefs and interests fill the lack of underdetermination. Quine's idea of a selective revision of hypotheses, as well as the neat incompatibility between holism and conventionalism, openly challenges the principles of relativism. Wittgenstein's work, which is not presented in book-form but rather as a tree, forces us to avoid aphoristic choices that credit any text-excising. This remark allows us to tackle the passages that sociological relativism is based on.Mathematical conventions are not anthropological objects. When Wittgenstein examines the "language-games," he only speaks of the functioning of natural language, not to be confused with scientific formal languages. We then should render the formula "language-game" by "well-defined, explicit and compulsory rules of communication", which is a much less attractive formula for relativism. Consequently, there does not exist a real continuity between the epistemologies of Duhem, Quine and Wittgenstein, and the recent works of the SSK.

Why did linear perspective rise in trecento–quattrocento central Italy rather than in any other cultural context? This book provides new insight into the question of the early Italian pioneership in perspective, building on the fact that many references to optics can be found in Renaissance treatises. The fact that most of the medieval optical manuscripts were written by Franciscan masters—the best known among them being Roger Bacon and John Pecham—suggests the need for a closer look at how the medieval universities (studia generalia) operated. An in-depth study of recruitment highlights the exceptional mobility of masters and lectors throughout Europe. However, through the thirteenth and fourteenth centuries, the closer a university was to central Italy, the more cosmopolitan it was. This is a result of the topology of the academic network, since cosmopolitanism depends on the studium’s closeness centrality. This is why, through the masters’ mobility, knowledge circulating in the network preferentially flowed into central Italy.

In view of the progress made in recent decades in the fields of stemmatology and the analysis of geometric diagrams, the present article explores the possibility of establishing the stemma codicum of a handwritten tradition from geometric diagrams alone. This exploratory method is tested on Ibn al-Haytham’s Epistle on the Shape of the Eclipse, because this work has not yet been issued in a critical edition. Separate stemmata were constructed on the basis of the diagrams and the text, and a comparison showed no major differences. The greater reliability of a stemma codicum constructed on the basis of the diagrams rather than the text of a mathematical work is discussed and preliminary conclusions are drawn

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.