However important it may be to know the motives according to which man kind has really acted hitherto, perhaps the belief in this or that motive, and therefore that which mankind has assumed and imagined to be the actual mainspring of its activity hitherto, is some thing still more essential for the thinker to know. For the internal happiness and misery of men have always come to them through their belief in this or that motive, not however, through that which was actually the motive! All about the latter has an interest of secondary rank.