The Dating and Significance of Galileo’s Pisan Manuscripts

Abstract

Among Professor Drake’s many contributions to our knowledge of Galileo and his work, the research he has done on the watermarks discernible in Galileo’s surviving manuscripts must surely rank the most significant. It was this line of attack that enabled him to date the large number of fragments long known to be associated with the second science set out in Galileo’s Two New Sciences of 1638, namely, that devoted to De motu locali, which in turn led to two important discoveries. The first was chronological, for it showed that the great bulk of these fragments date from Galileo’s early period, before he made his momentous discoveries with the telescope. The second was methodological, for it gave nearly indisputable evidence of an experimental program in which Galileo was engaged while writing the fragments, mainly at Padua and prior to 1610. Such a program, undertaken early in Galileo’s life, reveals a strong empiricist strain in his thought and counts heavily against his ever being a Platonist, as alleged by some Galileo scholars.¹