All of humanity's problems stem from man's inability to sit quietly in a room alone.
People almost invariably arrive at their beliefs not on the basis of proof but on the basis of what they find attractive.
When I consider the short duration of my life, swallowed up in the eternity before and after, the small space which I fill, or even can see, engulfed in the infinite immensity of spaces whereof I know nothing, and which know nothing of me, I am terrified, and wonder that I am here rather than there, for there is no reason why here rather than there, or now rather than then. Who has set me here? By whose order and design have this place and time been destined for me?—Memoria hospitis unius diei prætereuntis. It is not well to be too much at liberty. It is not well to have all we want. How many kingdoms know nothing of us! The eternal silence of these infinite spaces alarms me.
He who is in love is wise and is becoming wiser, sees newly every time he looks at the object beloved, drawing from it with his eyes and his mind those virtues which it possesses.
It is only with the heart that one can see rightly; what is essential is invisible to the eye.
In every systematic inquiry where there are first principles, or causes, or elements, knowledge and science result from acquiring knowledge of these.