"Common Sense is that which judges the things given to it by other senses." — Leonardo da Vinci

All knowledge which ends in words will die as quickly as it came to life, with the exception of the written word: which is its mechanical part.

It seems that it had been destined before that I should occupy myself so thoroughly with the vulture, for it comes to my mind as a very early memory, when I was still in the cradle, a vulture came down to me, he opened my mouth with his tail and struck me a few times with his tail against my lips.

The spirit desires to remain with its body, because, without the organic instruments of that body, it can neither act, nor feel anything.

Weight, force and casual impulse, together with resistance, are the four external powers in which all the visible actions of mortals have their being and their end.