All our knowledge originates in opinion.

Anyone who invokes authors in discussion is not using his intelligence but his memory.

Human subtlety will never devise an invention more beautiful, more simple or more direct than does nature because in her inventions nothing is lacking, and nothing is superfluous.

The eye transmits its own image through the air to all the objects which face it, and also receives them on its own surface, whence the "sensus communis" takes them and considers them.

Small rooms or dwellings discipline the mind, large ones weaken it.

Nature varies the seed according to the variety of the things she desires to produce in the world.

That which has no limitations, has no form.