The man who has no tincture of philosophy goes through life imprisoned in the prejudices derived from common sense, from the habitual belief of his age or his nation, and from the convictions which have grown up in his mind without the co-operation or consent of his deliberate reason. To such a man the world tends to become definite, finite, obvious; common objects rouse no questions, and unfamiliar possibilities are contemptuously rejected. 

  - Bertrand Russell, The Problems of Philosophy (Oxford University Press) Chapter 15