"If geometry were as much opposed to our passions and present interests as is ethics, we should contest it and violate it but little less, notwithstanding all the demonstrations of Euclid and Archimede…"

"I hold that the mark of a genuine idea is that its possibility can be proved, either a priori by conceiving its cause or reason, or a posteriori when experience teaches us that it is actual in nature."

"For since it is impossible for a creature to be perfect, the universe would be even less perfect if it contained only perfect creatures."

"He who does not act does not exist."

"There are two labyrinths of the human mind: one concerns the composition of the continuum, and the other the nature of freedom, and both spring from the same source—the infinite."