Cogito cogito ergo cogito sum -- "I think that I think, therefore I think that I am;" as close an approach to certainty as any philosopher has yet made.
Ambrose BierceA person who doubts himself is like a man who would enlist in the ranks of his enemies and bear arms agains himself. He makes his failure certain by himself being the first person to be convinced of it.
Ambrose BierceI think love is the most unbelievable, and critical, thing in civilization. Everything else is very mechanical and predictable, but love, you can't catch it.
Ambrose Bierce