“ Thought in movement has for its only conceivable motive the attainment of belief, or thought at rest. Only when our thought about a subject has found its rest in belief can our action on the subject firmly and safely begin. ”
 William James, The Varieties of Religious Experience (1902). copy citation

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“An American philosopher of eminent originality, Mr. Charles Sanders Peirce, has rendered thought a service by disentangling from the particulars of its application the principle by which these men were instinctively guided, and by singling it out as fundamental and giving to it a Greek name. He calls it the principle of pragmatism , and he defends it somewhat as follows:295 —
Thought in movement has for its only conceivable motive the attainment of belief, or thought at rest. Only when our thought about a subject has found its rest in belief can our action on the subject firmly and safely begin. Beliefs, in short, are rules for action; and the whole function of thinking is but one step in the production of active habits. If there were any part of a thought that made no difference in the thought's practical consequences, then that part would be no proper element of the thought's significance.” source