Dominique Raynaud

Il Commentario III di Lorenzo Ghiberti (1381-1455), conosciuto attraverso un manoscritto non autografo del Quattrocento (Firenze, B.N.C. II.I.33), è stato oggetto di numerose edizioni e studi critici. Dopo lo primo studio di Schlosser, la ricerca delle fonti ha fatto notevoli progressi. L’edizione di Bergdolt costituisce oggi lo studio più accurato delle fonti: sembra che Lorenzo Ghiberti si sia servito soltanto dei testi di Vitruvio, Alhazen, Avicenna, Averroè, Bacone, Peckham et Witelo. Benché la maggior parte del testo sia dedicata all’ottica, l’authorship del Ghiberti è ormai ridotto a un centinaio di righe in cui non si trata mai d’ottica. Questo trattato è cosparso de irregolarità che danno piuttosto la sensazione di una “concatenazione” di testi. Varie ipotesi sono state avanzate per spiegare queste irregolarità lessicali e sintattiche (disordini legati all’afasia, redazione condotta sotta dettatura di un traduttore, effetto di un desiderio di mobilità sociale). Queste ipotesi spiegherebbero congiuntamente sia l’interesse palese di Ghiberti per l’ottica che le strane imperfezioni del Commentario III.

La “prospettiva”, come sistema di rappresentazione, deriva il suo nome dalla parola perspectiva che designava l’ottica nel Medioevo latino. Questo collegamento dipende dal fatto che alcuni dei princìpi della prospettiva provengono dalle teorie della visione. Tra i due insiemi, esistono sia rapporti di continuità che di discontinuità. La continuità è stabilita dallo studio dei paralleli testuali. Tuttavia esistono due biforcazioni principali che hanno segnato l’evoluzione successiva della perspectiva artificialis. Oltre il rapporto fra scienza e tecnica che le caratterizza, la perspectiva medievale era tricefala (optica, catoptrica, dioptrica), mentre la prospettiva sarà uno studio della visione diretta. La perspectiva presupponeva la visione binoculare, mentre la prospettiva linéaire adotterà la visione monoculare.

Si presume che Erazm Ciołek Witelo (Vitelion, Vitellio, Vitello, Vitulio, ecc., ca. 1230–dopo 1278) sia nato a Legnica, nella bassa Silesia, da padre tedesco e madre polacca, come suggerito dalla dedica dei Perspectivae libri decem a Guglielmo di Moerbeke (Veritatis amatori fratri Guilielmo de Morbeka, Witelo filius thuringorum et polonorum eterne…) Witelo si laureò presso la facoltà degli arti di Parigi negli anni 1250, prima di studiare diritto canonico a Padova tra il 1262 e il 1268. Nel 1268–9, si unì alla corte di Viterbo, dove fece amicizia con Guglielmo di Moerbeke, traduttore di varie opere dal greco al latino, come quelle di Aristotele o Proclo e, per quanti riguarda l’ottica, la Cattotrica di Erone di Alessandria (Vaticano, BAV, Ottob. lat. 1850)…

Johannes Müller, noto con il nome latino di Regiomontano (1436–1476), nacque a Unfinden, vicino a Königsberg, il 6 giugno 1436. Studiò matematica e astronomia a Lipsia prima di andare a Vienna per seguire le lezioni di Georg von Peurbach. Dopo la morte di questo, nel 1461, andò a Roma dove divenne amico del cardinale Basilio Bessarione, legato del Papa presso la Repubblica di Venezia. Imparando il greco con Bessarione, Regiomontano si interessò alle opere matematiche dell’antichità. Fu anche un’epoca in cui viaggiò nel nord d’Italia…

Giovanni Pecham (Peccam, Peckam, Peckham), nato intorno al 1225 a Patcham (Sussex) entrò nell’ordine francescano (Ordo Fratrum Minorum) in una data sconosciuta intorno al 1250–6. Fu mandato allo studium di Parigi per studiare teologia (1257–9). Pecham probabilmente rimase a Parigi fino al 1272, dove poté incontrare Ruggero Bacone, che risiedeva lì tra 1257 e 1267 o 1280. Alla fine di questo periodo, divenne magister regens dello studium parigino (1269–71) prima di essere nominato l’undicesimo lettore a Oxford (1272–4)…

Ruggero Bacone (ca. 1220–ca. 1292) nacque a Ilchester, nel Sommersetshire, in una data sconosciuta intorno al 1214, o più probabilmente 1220. Bacone ha studiato a Oxford (1234–42) prima di andare a Parigi, dove diviene maestro d’arte nel 1242 ed insegna subito dopo la filosofia di Aristotele. Ritornato a Oxford tra il 1248 e il 1251, abbandona la filosofia di «studio e commento» per dedicarsi allo studio della scienza sperimentale – una svolta decisiva che potrebbe essere spiegata dalla sua introduzione nell’ambiente di Roberto Grossatesta e del sue discepolo Adam de Marisco, magister regens dello studium di Oxford…

Una nota dello storico bizantino Giovanni Tzetzes ci permette di datare la nascita di Archimede, figlio dell’astronomo Fidia, circa 287 a.C. La tesi, sostenuta da Clagett, che avrebbe studiato ad Alessandria prima di tornare in Sicilia, deve essere abbandonata perché non ci sono prove che Eratostene, Conone e Dositeo, a cui Archimede dedica i suoi trattati, vivessero in Egitto. Archimede era un intimo amico di Ierone, re di Siracusa. Secondo la leggenda, fu lo stesso Ierone a chiedergli di determinare se una corona fosse fatta di oro puro o di una lega, un problema che Archimede avrebbe risolto inventando la misurazione del volume di un corpo irregolare per spostamento di acqua…

Poco si sa circa la vita di Abū Yūsuf Yaʿqūb ibn Isḥāq al-Kindī, conosciuto nel mondo latino come Alkindi. Secondo i bio-bibliografi arabo, sarebbe nato agli inizi del IX secolo a Kūfa, dove il padre serviva come governatore. Alcuni storici hanno sostenuto che al-Kindī avrebbe preso parte alla grande impresa di traduzione dal greco delle opere scientifiche guidata dal califfo al-Maʾmūn (regno tra 813-833) nella famosa Casa della Sapienza (bayt al-ḥikma), ma il bio-bibliografo più vicino alle fonti, Ibn al-Nadīm, inserisce al-Kindī dopo Tolomeo e Teone d’Alessandria, mentre i nomi dei sessanta traduttori della Casa della Sapienza appaiono in un’altra sezione del Fihrist.

I submit that, in order to fulfill its fundamental aspiration to be a science, sociology must reconnect – beyond classical sociologists – with the authors of prior generations who prepared its emergence. They are Condorcet, Laplace, Poisson, Arago, Quetelet and Verhulst, all of whom predate the creation of the word “sociology” by Auguste Comte. I show that these authors had a scientific project for sociology, and that in its embryonic stage this science has been silenced by the official sociology established by Auguste Comte and his successors. This chapter reviews the ideas of these authors, revisits the aversion of the founder of sociology to his predecessors, and tries to draw consequences for the pursuit and further development of scientific sociology.

This paper attempts to clarify the concepts of freedom and constraint through a study of architectural design work, an activity that its practitioners represent as a constraining space, though they in fact manage to find new solutions within. The study aims at both factual and theoretical results: factual in that the difficulties of exercising this profession seem to be due less to constraints than the excessive degree of responsability and near impracticability of the studies they induce; theoretical because certain facts suggest that a fundamental revision of the negative relation generally understood to obtain betwwen freedom and constraint is in order. Two examples of such facts: prohibitions are not as constraining as prescriptions, and certain 'absorption' strategies can open a path to freedom while following a given constraint 'to the letter'.

Dans les Due regole della prospettiva pratica, Vignola et Danti condamnent un système hétérodoxe de perspective à deux points de fuite. Après avoir analysé les épures de trente tableaux du Moyen Âge répondant à cette définition, il est montré que ces oeuvres ne répondent à aucun type connu de perspective. Elles échappent notamment aux règles de la « perspective synthétique » (Panofsky, White) et à celles de la « perspective bifocale » (Parronchi). Des arguments sont alors avancés pour reconnaître une application des principes de la vision binoculaire contenus dans les traités d’optique médiévale (Ibn al-Haytham et ses commentateurs latins). Sous cette hypothèse, la restitution des géométraux à partir des vues perspectives conduit à des résultats cohérents et conformes aux modèles architecturaux contemporains. Ces arguments incitent à reconnaître une application qualitative de la « perspective centrale binoculaire » au Moyen Âge.

Panofsky and White hypothezised that « axial constructions » result from a projective system in which object’s measurements are taken on an projection circle, before being moved to the picture plane (i.e. synthetic perspective). Although this construction has been yet criticized regarding painter’s ability to apply it, the idea of using synthetic perspective regularly reappears for it never has been examined in detail. But from a mathematical point of view, this system is simply impossible because, in a synthetic perspective, three vanishing lines taken on the same side of the axis cannot be parallel nor admit a convergence point. The falsification of Panofsky-White’s conjecture puts and end to a long series of contradictory judgements on this problem, and opens the way to a radical reinterpretation of axial constructions.

A wide range of paradigms is often taken as a sign of the prescientific status of a discipline. That's why this paper is focused on the reduction of sociological paradigms. It is shown that, beyond the differences between Simmel's formal sociology and Weber's comprehensive sociology, they are reduceable to the common paradigm of nominalist sociology, of whom we propose the axiomatisation. Moreover, the paradigms' reduction accentuates the continuity between all the programmes that claim one or the other of those legacies (actionnism, strategical analysis, relationism, practical interactionnism, network sociology). Such differences don't result from the incommensurability of paradigms; they are due to the fact that these research programmes focuse on different facets of a same paradigm.

Le De lunularum quadratura (Firenze, Biblioteca Nazionale Centrale, ms. Magl. V 243, fos 77v-79r) est un court opuscule traditionnellement attribué à Leon Battista Alberti selon une conjecture qui remonte à la première édition de ce texte par Girolamo Mancini. Cette attribution ne repose sur aucune preuve directe. Elle résulte de ce que le traité est joint à une copie des Ex ludis rerum mathematicarum du même auteur et de l’intérêt qu’il portait aux sciences exactes. Le De lunularum quadratura – qu’il faudrait nommer Modo di misurare una figura biangula par son incipit – doit être retiré à Leon Battista Alberti. Il s’agit d’un texte apocryphe qui n’est autre qu’une version corrompue de la première quadrature d’Hippocrate tirée du commentaire de Simplicius sur la Physique d’Aristote, traduite en arabe, en latin, puis en italien, soit par le traducteur de la Perspectiva d’Ibn al-Haytham et du Liber de crepusculis d’Ibn Mu‘ādh, soit d’après lui. Au total, entre le VIe et le XIVe siècle, le texte a effectué une pérégrination complète autour du bassin méditerranéen. Nous donnons l'édition critique et la traduction française du texte.

The prevailing sociological explanations of art values are based on traditional factors (they are contracted by custom) or affective factors (they arise out of an emotional link to artwork). A series of four experiments focused on the construction of architectural values and representations shows that rational factors should not be underestimated in the course of this process. Artistic values and representations can be understood as rational inferences, whom production follows Maupertuis’ principle of lesser action.

Le « contexte » est un concept qui, même réduit à la portion congrue dans le cadre de l’individualisme méthodologique, joue un rôle dans beaucoup d’explications sociologiques. Il est avancé quatre arguments : 1° « individu-en-contexte » est forgé sur le modèle « figure-sur-fond » de la Gestaltpsychologie dont le holisme est incompatible avec les paradigmes individualistes ; 2° contrairement au « fond » de la Gestalt, le « contexte » des sociologues est indéfini quant à l’échelle, quant aux limites et quant au contenu ; c’est pourquoi il ne peut être en position de sujet causal d’une expression bien formée : seuls les individus sont capables d’action ; 3° dans ses aspects objectifs, le contexte est réductible au réseau social de l’individu ; 4° dans ses aspects subjectifs, le contexte est réductible à une croyance de l’individu. La sociologie des sciences fournit l’exemple d’une telle redéfinition spontanée : l’action des chercheurs a d’abord été référée à la « communauté scientifique », puis aux « communautés auto-régulées », aux « sous-communautés spécialisées », aux « collèges invisibles » et enfin aux « réseaux de collaboration scientifique ». Dernier de ces remaniements, le réseau de collaboration permet de reconstruire plus finement la perception qu’un chercheur se fait de sa discipline et contribue à expliquer sa productivité scientifique. Du point de vue de l’individualisme structural, il n’est pas indispensable de maintenir le concept de contexte sinon comme fiction ou façon de parler : les usages explicatifs sont illégitimes ; l’usage référentiel peut être évité en remplaçant contexte par croyance et réseau social.

This paper is a study of architectural design process. The explanation of an elementary change of state of the project is faced with two cases : (i) change of state transforms the morphological model, in which case schema operator is needed to describe the design ope- ration (Raynaud, 1999); (ii) change of state does not involve such a transformation and just consists in a size adjustment. The present paper examines the second case onto several examples (Gio Ponti, Sebastiano Serlio, Villard de Honnecourt). It is shown that schema operator is also required to describe the design operation in its entirety. But, since scale is regarded as a design operator by architecturology, the connection between schema and scale must be clarified. The reasons leading to the characterization of scale and schema as design co-operators are reviewed.

O artigo trata da situação específica da arquitetura em relação à semântica. Inicialmente pensado dentro do quadro da linguistica, a semântica foi aplicada a problemas onde não havia linguagem (semiótica). Seus conceitos têm que ser revisados para a aplicação à arquitetura. Propomos aqui o conceito de esquema dinâmico de modo a esclarecer a tese da semelhança semântica. Apesar da grande variabilidade do significado arquitetônico segundo o conceito sócio-histórico, tipos de significados podem ser distinguidos: pirâmides para subir ou descer, plantas em cruz para radiar, unir ou cruzar, etc. Este panorama leva a conclusões pouco compatíveis com a tese da comunicação em arquitetura.

Cet article se propose de contribuer au débat sur les méthodes de la sociologie des sciences à partir d’une étude empirique des déterminations de la vitesse de la lumière réalisées entre 1676 et 1983. Loin d’être construites et déconstruites à volonté, les valeurs de c ont subi un processus de révision tendanciellement unidirectionnel et irréversible. Les méthodes de détermination de c sont restées dans la course seulement quand elles étaient assorties d’une incertitude inférieure ou égale à la meilleure valeur connue. L’étude des «entrées» et «sorties» des méthodes sur le front de recherche met en évidence la nature de la compétition scientifique, forme d’«émulation redistributrice» différente de la rivalité politique ou de la concurrence économique. En parvenant à des résultats différents du constructivisme sur les thèmes de l’inscription littéraire, des jeux de construction/déconstruction, de la négociation et de la persuasion, l’article esquisse une sociologie internaliste des sciences, qui se donne pour objet d’étudier les aspects qui caractérisent la science en tant que science.

Recent works try to transpose the results of the anthropology of science and technics to architecture. This paper reviews every point of this transposition. Thanks to new researches, we have to admit the reality of projects' drift, the existence of a part of negociation in design, and the revisable nature of professional skills. But some works, maximizing these findings, reach questionable results. Drift does not turn project into a wholly unexpected process; negociation can hide other important social relations (as constraint or communication); actors' skills are not arbitrarily interchangeable. The failure of the transposition is then clarified by a comparison of architecture and industry design situations. Building being an only and setlled production, it is subjected to specific site constraints. Knowable ex ante, those constraints explain why design remains the hard core of architect's professional expertise, in spite of the increasing success of negociate activities. Certains travaux récents envisagent de transposer à l'architecture les résultats de l'anthropologie des sciences et techniques. L'article examine chaque point de la transposition. À la faveur des nouvelles recherches, on doit admettre une part de négociation dans la conception, et le caractère révisable des compétences professionnelles. Mais, en maximalisant ces conclusions, certains travaux parviennent à des résultats discutables. La dérive ne fait pas du projet un phénomène totalement imprévisible ; l'accent mis sur la négociation peut occulter d'autres rapports sociaux, comme la contrainte ou la communication d'informations ; les compétences des acteurs ne sont pas interchangeables à merci. L'échec de la transposition est explicité par une comparaison des situations de conception en architecture et dans l'industrie. Le fait que le bâtiment soit une production unique et située le soumet à des contraintes de site. Connaissables ex ante, ces contraintes expliquent pourquoi la conception demeure le noyau dur de l'expertise professionnelle de l'architecte, en dépit des succès rencontré par le thème de la négociation.

The study of architectural design bridges various approaches focusing on design sciences, cognitive psychology and architecturology. Architecturology aims to describe the full range of changes that appear during the design process. We are able to describe, by means of scales, the operations by which an architect gives size to the building. This modelling seems adequate when the morphological model is not adulterated during the design process (as in some projects of Jørn Utzon or Alvar Aalto). In other cases – as in some projects by Philibert de l'Orme, Ludwig Mies van der Rohe, Norman Foster – changes of state adulterate the very pattern of the morphological model. Such changes can no longer be covered by scale operators. Taking up an idea by Herbert A. Simon, it is suggested that the description of these new transformations requires another class of operators. These could be called schemata, with the term understood as the prototypical actions that could be rendered by basic verbs as open, close, separate, bind, etc.

From Panofsky, it is usually considered that vanishing axis compositions result from the rules of curvilinear perspective. This article disproves this evidence. It is shown that a lot of vanishing axis compositions can find support on the principles of binocular vision (hyp. I) exposed in medieval optics, rather than on any type of linear (hyp. II) or curvilinear perspective (hyp. III). The comparison of these three hypotheses shows that only the first one fits well with a set of medieval and renaissance paintings, while avoiding inconsistencies arising – and not yet satisfactorily explained – in the framework of linear or curvilinear perspective. Depuis les travaux de Panofsky, il est habituellement considéré que les compositions en axe de fuite résultent d’une application des règles de la perspective curviligne. Cet article réfute cette thèse. Il est montré qu’un grand nombre de compositions en axe de fuite peuvent s’expliquer par les principes de la vision binoculaire que l’on trouve dans les traités d’optique médiévale (hyp. 1), plutôt que par quelque autre type de perspective linéaire (hyp. 2) ou curviligne (hyp. 3). La comparaison de ces trois hypothèses montre que seule la première peut rendre compte d’un ensemble de peintures du Moyen-Âge et de la Renaissance, tout en évitant les incohérences qui surgissent – et ne sont pas adéquatement expliquées – dans le cadre de la perspective linéaire ou curviligne.

This paper tests the principle of an analysis of scientific contents, related to an examination of the norms of rationality. In the second half of XIIIth century, optics was a controversial topic on the matter of extramission vs. intromission of visual rays. Grosseteste, Bacon and Pecham took part to this dispute. The analysis of linguistic acceptations of truth in this time shows that the norms of rationality clearly partakes of authority. Now, following Augustine's authority, Franciscan scientists ought to have maintained the intromission thesis, but did not. Therefore, the study of this controversy escapes to the programme of relativism defended in the field of sociology of scientific knowledge. It incites to confine the analysis of contents to logical inconsistencies, axioms and postulates. Such an analysis so becomes congruent with anhistorical norms of rationality. Cet article se propose de tester le principe d'une analyse sociologique des contenus scientifiques reliée à un examen des normes de rationalité. Dans la deuxième moitié du XIIIe siècle, est apparu une controverse sur l'extramission vs. l'intromission des rayons visuels, à laquelle prirent part Grossesteste, Bacon et Pecham. L'analyse des acceptions du mot vérité à cette époque montre que les arguments d'autorité faisaient partie des normes de rationalité. Or, en suivant l'autorité de Saint Augustin, les savants franciscains auraient dû soutenir l'intromission, ce qu'ils ne firent pas. L'étude de cette controverse échappe donc au programme d'une sociologie des sciences relativiste. Elle incite à limiter l'analyse des contenus aux seules failles logiques, axiomes et postulats, et rend ainsi cette analyse congruente avec les normes anhistoriques de la rationalité.

The study of the dispute that broke out between the medical schools of Paris and Montpellier (1817-1852) shows that professional interests, but also philosophical and political factors drew the fitgets of Montpellier's school about its doctrine. But these factors are inable to explain the scientific contents. Further, the closure of the controversy did not result from a social negotiation of truth. It simply favoured the scholars who had major scientific productivity. This dispute so contradicts the principles of the relativistic program in the field of the sociology of scientific knowledge, and shows that some studies could have misunderstood the sense of a social determination of scientific contents. L'analyse de la controverse qui éclata entre les écoles de médecine de Paris et de Montpellier (1817- 1852) montre que des intérêts professionnels, mais aussi des facteurs philosophiques et politiques conditionnèrent la crispation de l'école de Montpellier sur ses positions doctrinales. Mais ces facteurs n'expliquent pas le contenu des théories. Le règlement de la controverse fut étranger à une négociation sociale de la vérité, et tourna à la faveur ceux qui eurent la productivité scientifique la plus élevée. Cette controverse, qui échappe aux principes du programme relativiste en sociologie des sciences montre que certaines études peuvent s'être méprises sur le sens d'une détermina- tion sociale des contenus scientifiques.

The controversy between Pasteur and Pouchet on spontaneous generation (1859-1864) has received great interest in the sociology of scientific knowledge. This paper shows that some statements were shifted by Pennetier’s biased version (1907). The study of the correspondence between Pouchet and the members of the Académie des Sciences reveals that Pouchet was on intimate terms with many members of this institution, and also that the two commissions appointed in 1862 and 1864 did not collude with any Pastorian lobby. The discovery of Pouchet’s forgery leads to a quite different estimate of this controversy. Pouchet’s defeat can be explained by his repeated retreats in front of the commissions, his dogmatic faith in heterogeny, lobbying by the press, and an immoderate need for glory. Beyond the lack of replies to the rationale against heterogeny, such a transgression of the norms of scientific ethos seems to have been a source of irritation among the Academicians.