This paper reconstructs the development of Mersenne's reflections concerning optics. I argue that Mersenne's optical writings provide crucial insights into Mersenne's Aristotelianism. I reconstruct Mersenne's attempt of explaining the new ideas on light, which were advanced by Kepler, Descartes and Hobbes within Aristotle's natural philosophy. Mersenne explained Kepler's work on light within the Scholastic tradition. In the 1640s, Mersenne was stimulated by the debate concerning Descartes' theory of light, which he accepted only in 1648. Indeed, Mersenne first explained Descartes' law (...) of refraction by means of Hobbes physics. However, Mersenne always wanted to remain faithful to Aristotle. (shrink)

Some philosophers of science suggest that philosophical assumptions must influence historical scholarship, because history (like science) has no neutral data and because the treatment of any particular historical episode is going to be influenced to some degree by one's prior philosophical conceptions of what is important in science. However, if the history of science must be laden with philosophical assumptions, then how can the history of science be evidence for the philosophy of science? Would not an inductivist history of science (...) confirm an inductivist philosophy of science and a conventionalist history of science confirm a conventionalist philosophy of science? I attempt to resolve this problem; essentially, I deny the claim that the history of science must be influenced by one's conception of what is important in science — one's general philosophy of science. To accomplish the task I look at a specific historical episode, together with its history, and draw some metamethodological conclusions from it. The specific historical episode I examine is Descartes' critique of Galileo's scientific methodology. (shrink)

Resumen La naturaleza de las entidades matemáticas ha sido un problema filosófico recurrente en diversas épocas; aquí mostraré que fue una pieza clave en la definición de las posturas ontológicas durante la Modernidad temprana. La piedra de toque para la fundamentación de los conocimientos científicos fue el carácter que se atribuyó a las entidades matemáticas -y, en general, a las entidades abstractas, incluidas las lógicas- en la filosofía natural. Expongo dos posiciones de la Modernidad: la que defendió René Descartes, quien (...) las concibió como entidades perennes, inherentes a la propia constitución y funcionamiento de la mente y la de autores como Pierre Gassendi y Marin Mersenne, quienes defendieron el origen empírico e instrumental de esas entidades.The status of mathematical entities has been a recurrent philosophical problem in different times; here I explain how it was a key piece in the definition of ontological positions during Early Modernity. The touchstone for the foundation of scientific knowledge was the character assigned to mathematical entities -and, in general, to abstract entities, including logical ones- within the natural philosophy. I sketch two modern positions: on the one hand, the one defended by René Descartes, who assigned mathematical items a status of perennial entities, inherent to the very constitution and operation of the mind and, on the other, the one supported by authors such as Pierre Gassendi and Marin Mersenne, who defended the empirical and instrumental origin of those entities. (shrink)

The category of sympathy marks a number of basic divisions in early modern approaches to action explanations, whether for human agency or for change in the wider natural world. Some authors were critical of using sympathy to explain change. They call such principles “unintelligible” or assume they involve “mysterious” action at a distance. Others, including Margaret Cavendish, Anne Conway, and Gottfried Wilhelm Leibniz, appeal to sympathy to capture natural phenomena, or to supply a backbone to their metaphysics. Here I discuss (...) how concerns about sympathetic actions form at least a partial background for differing seventeenth-century conceptions of what it is to explain action. I argue that critics of sympathy generally insist on an “atomistic” approach to action explanation, which makes primitively relational phenomena come out as problematic. Proponents of sympathy, by contrast, allow for a more holistic approach to action explanation, which allows for such basic connections. Hence, divergent attitudes toward sympathetic action in part explain differences in approaches to explanation. I conclude by showing how some of these core concerns fade into the background when in the eighteenth-century sympathy gets psychologised and individualised. (shrink)

It is difficult to evaluate the role of activity - of force or of that which has causal efficacy - in Descartes’ natural philosophy. On the one hand, Descartes claims to include in his natural philosophy only that which can be described geometrically, which amounts to matter (extended substance) in motion (where this motion is described kinematically).’ Yet on the other hand, rigorous adherence to a purely geometrical description of matter in motion would make it difficult to account for the (...) interactions among the particles that constitute Descartes’ universe, since the notions of extension and kinematical motion do not in themselves imply any causal agency. There is, after all, no reason to expect that a particle whose single essence is extension, even if we suppose it to be moving, should impart motion to another particle, while conversely, there is no reason to expect a resting particle to hinder the motion of an impinging one. Descartes' hankering for an austere ontology of matter in motion is in danger of excluding causal agency (force, conceived dynmically) from matter. To the modern reader it may seem obvious that Descartes did not get himself into such a fix, since matter in motion so readily reminds us of kinetic energy or of some more primitive notion of force. Yet by no means is it obvious that Descartes attributed causal efficacy to matter in motion per se. Serious scholars have held opposite positions on this issue. Westfall, Gabbey, and others’ have argued that although on the metaphysical plane Descartes attempted to eliminate force from his mechanical universe, nonetheless ‘force is a real feature’ of his mechanical world. The thrust of this view is that Descartes conceived of force as ‘the capacity of a body in motion to act’, by means of impact, upon other bodies. An opposing interpretation, defended here, is that Descartes did in fact deny causal agency to moving matter per se, restricting agency to immaterial substances such as the human mind, angels, and God. The intention of this interpretation is not to de-emphasize the role of matter in motion in Descartes’ explanation of nature, but rather to stress the fact that Descartes did not conceive of this moving matter dynamically. -/- Reprinted in Descartes, ed. by J. Cottingham, Oxford Readings in Philosophy (Oxford: Oxford University Press, 1998), 281–310. (shrink)

We re-examine Mersenne's critique of Giordano Bruno concerning the question of the extension of the universe and the plurality of worlds as well as that of universal animation. For this, it is necessary to distinguish, especially in the examination of the first question, the strictly cosmological problem from its metaphysical and theological foundation in which the relation between God and the universe is resolved. Mersenne's critique fundamentally concerns this second side of our problem, according to his conviction that Bruno repeats (...) the age-old errors of philosophical paganism and reaffirms an 'impiety' completely incompatible with Christian doctrine.------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------- -------------------------------------------------. (shrink)

: Marin Mersenne was central to the new mathematical approach to nature in Paris in the 1630s and 1640s. Intellectually, he was one of the most enthusiastic practitioners of that program, and published a number of influential books in those important decades. But Mersenne started his career in a rather different way. In the early 1620s, Mersenne was known in Paris primarily as a writer on religious topics, and a staunch defender of Aristotle against attacks by those who would replace (...) him by a new philosophy. In this essay, I would like to examine Mersenne's changing attitude toward Galileo. In the early 1620s, Mersenne lists Galileo among the innovators in natural philosophy whose views should be rejected. However, by the early 1630s, less than a decade later, Mersenne has become one of Galileo's most ardent supporters. How, then, did Mersenne learn to love Galileo? (shrink)

In the lively discussions on Galileo's laws of motion after the Pisan's death, we observe what might be called a new “Galilean affair.” That is, a trial brought against his new science of motion mainly by French and Italian Jesuits with the substantial adherence of M. Mersenne. This new trail was originated by Gassendi's presentation of Galileo's de motu not simply as a perfectly coherent doctrine, but also as a convincing argument in favor of the truth of Copernicanism.

In the lively discussions on Galileo's laws of motion after the Pisan's death, we observe what might be called a new “Galilean affair.” That is, a trial brought against his new science of motion mainly by French and Italian Jesuits with the substantial adherence of M. Mersenne. This new trail was originated by Gassendi's presentation of Galileo's de motu not simply as a perfectly coherent doctrine, but also as a convincing argument in favor of the truth of Copernicanism.