“While human ingenuity may devise various inventions to the same ends, it will never devise anything more beautiful, nor more simple, nor more to the purpose than nature does, because in her inventions nothing is lacking and nothing is superfluous.”

“Why does the eye see more clearly when asleep than the imagination when awake?”

“Every now and then go away, have a little relaxation, for when you come back to your work your judgment will be surer. Go some distance away because then the work appears smaller and more of it can be taken in at a glance and a lack of harmony and proportion is more readily seen.”

“If you are alone you belong entirely to yourself. If you are accompanied by even one companion you belong only half to yourself or even less in proportion to the thoughtlessness of his conduct and if you have more than one companion you will fall more deeply into the same plight.”

“How may paintings have preserved the image of a divine beauty which in its natural manifestation has been rapidly overtaken by time or death. Thus, the work of the painter is nobler than that of nature, its mistress.”

“The organ of perception acts more readily than judgment.”

“Experience is never at fault; it is only your judgment that is in error, in promising itself such results from experience as are not caused by our experiments. For having given a beginning, what follows from it must necessarily be a natural development of such a beginning, unless it has been subject to a contrary influence, while, if it is affected by any contrary influence, the result which ought to follow from the aforesaid beginning, will be found to partake of this contrary influence in a greater or lesser degree in proportion as the said influence is more or less powerful than the aforesaid beginning.”