"I used to measure the skies, now I measure the shadows of Earth.Although my mind was sky-bound, the shadow of my body lies here.[Epitaph he composed for himself a few months before he died]"
"We ought not to ask why the human mind troubles to fathom the secrets of the universe. The diversity of the phenomena of nature is so great, and the treasures hidden in the skies so rich, precisely in order that the human mind shall never be lacking in fresh nourishment."
"Geometry has two great treasures; one is the Theorem of Pythagoras; the other, the division of a line into extreme and mean ratio. The first we may compare to a measure of gold; the second we may name a precious jewel."
"Temporis filia veritas; cui me obstetricari non pudet.Truth is the daughter of time, and I feel no shame in being her midwife."