"The secrets of nature are not revealed to those who rely on books alone."

"There are many fables and falsehoods in the books of the Latins, which are taken for truths."

"It is necessary to know the causes of things, and not only their effects, if we wish to have perfect knowledge."

"The mathematical sciences are the gate and the key to the understanding of all other sciences."

"The study of magic, though often abused, contains many useful truths."