Right at the end of The Dialogue of the Two Chief World Systems, Galileo makes a distinction between the ‘sensible world’ and ‘a world on paper’(Galilei & Finocchiaro 2008, p.201). He is arguing that the true authority for our scientific theories is not what is written in books but what we can observe with our senses. I already implied at the end of the lecture on Galileo that we should treat this opposition with a little bit of suspicion since he might be guilty of rhetorical exaggeration. First of all, it is clearly not the case that Aristotle, or those who followed him did not use their senses, but equally, Copernicus’s idea hypothesis of heliocentrism was precisely that, and not something that one would come to simply by using one’s senses. Indeed, Descartes is being more honest than Galileo in this regard. He freely admits that the theory of…