Various kinds of ideas can be classified by their relationship to the authentication process. There are ideas systematically prepared for authentication ("theories"), ideas not derived from any systematic process ("visions"), ideas which could not survive any reasonable authentication process ("illusions"), ideas which exempt themselves from any authentication process ("myths"), ideas which have already passed authentication processes ("facts"), as well as ideas known to have failed- or certain to fail- such processes ("falsehoods" - both mistakes and lies).

Thomas Sowell