...the love of anything is the offspring of knowledge, love being more fervent in proportion as knowledge is more certain. And this certainty springs from a complete knowledge of all parts which united compose the whole of the thing which out to be loved.

All our knowledge hast its origins in our perceptions … In nature there is no effect without a cause … Experience never errs; it is only your judgments that err by promising themselves effects such as are not caused by your experiments … Science is the observation of things possible, whether present or past; prescience is the knowledge of things which may come to pass.

And you who wish to represent by words the form of man and all the aspects of his membrification, relinquish that idea. For the more minutely you describe the more you will confine the mind of the reader, and the more you will keep him from the knowledge of the thing described. And so it is necessary to draw and to describe.

If the painter has clumsy hands, he will be apt to introduce them into his works, and so of any other part of his person, which may not happen to be so beautiful as it ought to be. He must, therefore, guard particularly against that self-love, or too good opinion of his own person, and study by every means to acquire the knowledge of what is most beautiful, and of his own defects, that he may adopt the one and avoid the other.

They will say that I, having no literary skill, cannot properly express that which I desire to treat of, but they do not know that my subjects are to be dealt with by experience rather than by words. And [experience] has been the mistress of those who wrote well. And so, as mistress, I will cite her in all cases. Though I may not, like them, be able to quote other authors, I shall rely on that which is much greater and more worthy: on experience, the mistress of their masters.