How many times does a body under constant acceleration travel in the second half of its motion the distance covered in the first half of it? Is it possible to compare the whiteness of a pearl to that of snow? Is a human being two times, three times or infinitely more perfect than a horse? In the late Middle Ages, these questions were hotly debated in relation to the problem of quantifying forms. This book is about understanding why these questions arose and how some of them contributed to the development of scientific knowledge.