The greatest deception men suffer is from their own opinions. - Leonardo da Vinci

It is impossible that the eye should project from itself, by visual rays, the visual virtue, since, as soon as it opens, that front portion [of the eye] which would give rise to this emanation would have to go forth to the object and this it could not do without time. And this being so, it could not travel so high as the sun in a month's time when the eye wanted to see it.

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.

It's not enough that you believe what you see. You must also understand what you see.