The man who has no tincture of philosophy goes through life imprisoned in the prejudices derived from common sense, from the habitual beliefs of his age or his nation, and from 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.
Source: The value of philosophy' in The Problems of Philosophy, 1912
More info.:http://russell-j.com/R601.HTM