Part Two
SEEING IS BELIEVING
They are deceiv’d that acquiesce to things which they have heard, and believe not what they have seen.
– Thomas Bartholin, The Anatomical History (1653)1
Part Two begins in the early fifteenth century, and then follows issues related to sight through into the eighteenth century. Our starting point in Chapter 5 is the invention of perspective painting, which involved the application of geometrical principles to pictorial representation. These same principles led astronomers to take a new interest in measuring distances in order to establish exactly where certain objects – new stars – were in the heavens. Such activities established a new confidence in the power of mathematics to come to grips with nature, and this chapter follows this process through to Galileo. The second chapter, Chapter 6, looks at the impact of telescopes and microscopes on people’s sense of scale: human beings suddenly came to seem insignificant in the vast spaces which the telescope opened up, while the microscope exposed a world in which complexity seemed to reach right down to the smallest imaginable creatures, so that it became commonplace to imagine that fleas might have fleas, and so on, ad infinitum.