Optimism — the doctrine or belief that everything is beautiful, including what is ugly.
A person who doubts himself is like a man who would enlist in the ranks of his enemies and bear arms against himself. He makes his failure certain by himself being the first person to be convinced of it.
Who never doubted, never half believed. Where doubt is, there truth is — it is her shadow.
Logic: The art of thinking and reasoning in strict accordance with the limitations and incapacities of the human misunderstanding.