The History of scepticism from Erasmus to Spinoza is often called upon to support three theses: first, that Descartes had a dogmatic notion of systematic knowledge, and therefore of physics; second, that the hypothetical epistemology of physics which spread during the xviith century was the result of a general sceptical crisis; third, that this epistemology was more successful in England than in France. I reject these three theses: I point first to the tension in Descartes’ works between the ideal of (...) a completely certain science and a physics replete with hypotheses; further, I argue that the use of hypotheses by mechanical philosophers cannot be separated from their conception of physics; finally I show that, at the end of the xviith century, physicists in France as well as in England spoke through hypotheses and I examine different ways of explaining this shared practice. Richard H. Popkin’s book serves therefore as a starting point for insights into the general problem: to what extent and for what reasons some propositions in physics have been presented as hypotheses in the xviith century? (shrink)

Aristotelianism remained the dominant influence on the course of natural philosophy taught at the University of Paris until the 1690s, when it was swiftly replaced by Cartesianism. The change was not one wanted by church or state and it can only be understood by developments within the wider University. On the one hand, the opening of a new college, the Collège de Mazarin, provided an environment in which the mechanical philosophy could flourish. On the other, divisions within the French Catholic (...) Church between Austinians and Molinists led to Cartesianism finding support within an important section of the faculty of theology, which was the traditional guardian of philosophical orthodoxy. The conversion of the University of Paris to Cartesianism had important consequences. It encouraged similar changes to the natural philosophical curriculum throughout France and affected the structure and raison d'être of the Académie des Sciences. (shrink)

In 1675, Burchard de Volder (1643–1709) was the first professor to introduce the demonstration of experiment into a university physics course and built the Leiden Physics Theatre to accommodate this new pedagogy. When he requested the funds from the university to build the facility, he claimed that the performance of experiments would demonstrate the “truth and certainty” of the postulates of theoretical physics. Such a claim is interesting given de Volder’s lifelong commitment to Cartesian scientia. This chapter will examine de (...) Volder’s views on experiment and show that they are not Newtonian or inductivist, as is sometimes claimed. While de Volder thinks we need deductive reasoning from first principles to provide evidence of the certainty of the content of our physical theories, he also contends that we need experiment to provide evidence of the certainty of the existence of the particular bodies those theories discuss. This approach to experiment is based on a distinction between rational certainty and the certainty of material bodies in the actual world. While this account is deeply influenced by Descartes, it is importantly different than Descartes’ distinction between absolute and moral certainty. De Volder’s “Cartesian Empiricism” is best understood as a continuation and further development of a long tradition of teaching through observation at Leiden. (shrink)

Much has been written about Robert Hooke's so-called ‘Discourse of Earthquakes’, the series of lectures he delivered before the Royal Society of London over the years 1667–1700. The chief points of the lectures are thus well known: fossils are the remains of once-living organisms, and their burial in rather odd places within the earth's crust can be explained by the dislocations of land and sea resulting from earthquakes.

Defining experiment was particularly vexed in the realm of anatomical dissection and vivisection. Was dissection merely descriptive, or something more? Harvey's discovery of the circulation of the blood and Aselli's discovery of the so-called lacteal veins shaped much anatomical research between the late 1620s and the 1650s. While the techniques of dissection and vivisection gained wide use, there was much debate on the validity of the circulation in particular, and its relationship to the lacteal veins. Critics, particularly the French anatomist (...) Jean Riolan, but also the natural philosopher Pierre Gassendi, focused on the lack of causation in Harvey's method and the lack of medical use and not on his use of vivisection. Jean Pecquet's discovery of the thoracic duct in 1651 changed the terms of the debate by definitively connecting the circulation with the lacteals. Riolan's critiques of Pecquet in the 1650s show profoundly differing notions of the purpose of dissection. While Gassendi eventually accepted Harvey's concept of the circulation, Riolan never did. (shrink)

The ArgumentThis essay describes the emergence and stabilization in French and English experimental accounts, in second half of the seventeenth century, of the narrative sequence: X did (some process in the laboratory) and X saw (something happen), where X stands for a pronoun, I or we in English,je, nousoronin French. Focussing on the French case, it shows how the use of the collective pronounonin the experimental accounts registered in the files of the Académie des Sciences is directly related to the (...) will of this newly created institution to assert a collective authority on the production and legitimization of experimental matters-of-fact produced in the laboratory. It is argued, through the case of the discovery of the blind spot in the eye by Mariotte, that this new narrative form imbeds a construal of the experiment as a public spectacle, and of the proof as a witnessing event, which eludes the Academy's attempts to monopolize the process of fact validation and favors the diffusion and display of experiments in front of larger audiences. The question of whether a privileged witness such as the King of France who patronized the Academy could not have constituted by himself a suitable audience to ensure a full legitimization of experimental matters-of-fact while remaning within the bounds of academic practices is addressed. It is answered in the negative by providing evidence for the lack of interest of the absolute monarch in experiments. On the other hand, the outdoor practices of observation and measurement are shown to interfere in a constructive manner with the absolutist power and to capture the attention of the absolutist monarch, where laboratory experiments had failed. It is proposed that natural philosophers in the early modern period bear the burden of proof in buying credibility for the phenomena they try, by paying a tribute to the standing of the patrician elites that witness their experiments. This makes sense in a straightforward manner of the lack of interest of the King of France in a practice which exalts the power of the very group he is trying hard to control through the absolutist structure of power. (shrink)

Les philosophes naturels du XVIIe siècle accordent une importance croissante aux faits nouveaux et singuliers construits par des démonstrations spectaculaires réalisées devant témoins. Cet essai tente de montrer comment cette évolution s’opère comme une synthèse de deux courants auparavant disjoints, d’un côté la pratique coopérative et informelle, critique sans être véhémente, de savants dont Mersenne constitue un bon exemple dans les années 1630, et de l’autre celle des alchimistes, remettant radicalement en cause les savoirs traditionnels tout en restant viscéralement attachés (...) au secret. On montrera comment le cercle parisien qui se réunit autour du même Mersenne au milieu du siècle pour débattre des expériences du vide réalise cette synthèse particulière. Mais dans une communauté érudite intéressée surtout à employer les faits expérimentaux comme matériau nouveau dans les disputes philosophiques, et pour laquelle la correspondance privée constitue la principale source d’information sous la forme de narrations circonstanciées par des témoins des événements singuliers survenus au cours de démonstrations expérimentales, le récit à la première personne apparaît comme une ressource superflue lorsqu’il s’agit de passer au format imprimé; Pascal, par exemple, recourt dans ses traités à une description des expériences se déployant sur un registre hypothétique et syllogistique qui exclut la narration directe. Le succès ultérieur des techniques matérielles et littéraires administrant la preuve en donnant à voir le protocole expérimental peut alors être mieux compris si l’on considère la parenté que celles-ci entretiennent avec les pratiques de la lecture publique traditionnelles dans les cercles érudits, proximité qui leur permet d’enrichir la signification et d’accroître la force de persuasion de l’expérience artificielle aux yeux des mêmes audiences. (shrink)