Ideas being only accessible to crowds after having assumed a very simple shape must often undergo the most thoroughgoing transformations to become popular. It is especially when we are dealing with somewhat lofty philosophic or scientific ideas that we see how far-reaching are the modifications they require in order to lower them to the level of the intelligence of crowds. These modifications are dependent on the nature of the crowds, or of the race to which the crowds belong, but their tendency is always belittling and in the direction of simplification.This explains the fact that, from the social point of view, there is in reality scarcely any such thing as a hierarchy of ideas—that is to say, as ideas of greater or less elevation. However great or true an idea may have been to begin with, it is deprived of almost all that which constituted its elevation and its greatness by the mere fact that it has come within the intellectual range of crowds and exerts an infiuence upon them.