In what sense is the passage a challenge to medieval views and methods?
"Philosophy is written in the great book of the universe which lies always open. But we must first understand the language and the character in which it is written. That language is mathematics. Its characters are triangles, circles, and other geometric figures, without which we cannot, humanly speaking, understand the words, and wander aimlessly through a dark labyrinth." --Galileo, Il Saggiatore (The Assayer), 1623
Source: Ruoff, Henry W. (ed). "Masters of Achievement: The World's Greatest Leaders in Literature, Art, Religion, Philosoph, Science, Politics, and Industry."