  At the beginning of an essay on void and infinite space, Koyré quotes a passage from Duhem that has become infamous: “If we were obliged to assign a date to the birth of modern science, we would undoubtedly choose 1277, when the Bishop of Paris solemnly proclaimed that a multiplicity of worlds could exist, and that the system of celestial spheres could, without contradiction, be endowed with straight line motion” (1906–13, II.411; see also 1913–59, VII. 4). Koyré calls the two theses from the condemnations of 1277 “absurdities,” noting that they arise in a theological context, and rejects Duhem’s date for the birth of modern science; he remarks that Duhem gives another date elsewhere, corresponding to Buridan’s impetus theory being extended to the heavens, but dismisses it also, saying that “it is as false as the first date” (1961, 37n). For Koyré, the introduction of Platonic metaphysics, the mathematization of nature, marks a break with the Aristotelian Middle Ages.