leonardo

A well-spent day brings happy
sleep.

Leonardo da Vinci



All our knowledge has its origins
in our perceptions.

Leonardo da Vinci



Although nature
commences with reason and ends in experience it is

necessary for
us to do the opposite, that is to commence with experience

and
from this to proceed to investigate the reason.

Leonardo da
Vinci



Anyone who conducts an argument by appealing to
authority is not using

his intelligence; he is just using his
memory.