As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality. (Albert Einstein)
A man is a critic when he cannot be an artist, in the same way that a man becomes an informer when he cannot be a soldier. (Gustave Flaubert)
A man lives by believing in something, not by debating and arguing about many things. (Thomas Carlyle)