A world of words: Rereading Galileo's grand book of philosophy from Il Saggiatore.

One of the most famous passages in Galileo's Il Saggiatore is his declaration that "philosophy is written in this grand book, the universe, which stands continually open to our gaze". He opposed this book of nature with what he claimed was his opponent Orazio Grassi's understanding of philosophy -- "a book of fiction, productions in which the least important thing is whether what is written there is true". This paper seeks to situate this passage within the larger debate between Galileo and Grassi about the relationship between poetry and natural philosophy over the course of their publications regarding the comet controversy of 1618. During their back and forth, Galileo had claimed that "nature takes no delight in poetry", which Grassi had turned on him by alleging that he was too serious if he could not appreciate a poetic flourish in a learned debate such as theirs. This was a major insult given how central poetry and letters were to any early modern discourse. This paper argues that Galileo's "grand book" responded to this insult by both doubling down on his poetry-nature claim and illustrating that he was more familiar with poetry than Grassi. He accomplished both by referring to debates about epic poetry in late sixteenth-century Italy. This connection sheds new light on a passage that seemingly repudiates poetry, as well as contributing to scholarship that has sought to reevaluate the mathematician's engagement with the rich world of early modern Italian poetry. [ABSTRACT FROM AUTHOR]