The fundamental cause of trouble in the world is that the stupid are cocksure while the intelligent are full of doubt. (Bertrand Russell)

We have art to save ourselves from the truth. (Friedrich Nietzsche)

Facts are the enemy of truth. (Don Quixote – Man of La Mancha)

Each problem that I solved became a rule which served afterwards to solve other problems. (Rene Descartes, Discours de la Methode)