: 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 his review of my Prelude to Galileo, Ernan McMullin rejects my emendation of Pierre Duhem's “continuity thesis” wherein I develop the case for a pronounced medieval-scholastic influence on Galileo's science based on parallels between Galileo's early Latin compositions and lectures given by contemporary Jesuits at the Collegio Romano. He does so on two grounds: that the evidence of derivation I provide, using textual parallels, is so strong that it refutes the claim for any intellectual influence, being a better instance (...) of mindless copying than one of personal appropriation; and that, in any event, the logical structure of the argument which I attribute to Galileo's mature work is not that of demonstration ex suppositione as understood by Aquinas, and so the example I provide of Galileo's use of suppositio “does not link him in any significant way to the specifically Thomist tradition of natural science”. An adequate reply to this critique would require the introduction of more historical evidence than would be appropriate for the pages of this journal. A few remarks, however, may be in order concerning such evidence which bears directly on McMullin's first ground, and concerning the implications of this evidence for contemporary philosophy of science, which bear on his second. (shrink)