  What was new to Rehberg's historicism was his critique of reason. His skepticism regarding the practical powers of reason gave historicism a new firmer foundation, one deeper than that dug by Möser or Herder.  The ultimate upshot of his skepticism, as we have seen, is that there is a gap between theory and practice, between reason and conduct, in the realms of morality and politics.  Since reason cannot lay down specific maxims for moral conduct, and since it cannot determine the specific form of a constitution, it proves to be a useless guide to moral and political action.  What fills the gap between theory and practice is, for Rehberg, nothing less than history.  There are two senses in which this is the case.  First, we determine the specific maxims of our moral conduct, or the proper political constitution for a country, only by judging their utility, by seeing how well they fit into their cultural context, which is the product of history.  Second, we sometimes have to lay aside utility and determine how to act by precedent and tradition, by learning the customs of a culture; but precedent, custom and tradition are also results of history.  Both points show, Rehberg believes, that we are not completely free moral agents who simply choose to become part of a culture, and who choose principles of action based on pure reason alone; rather, we are born into our culture, which shapes our very identity, and which supplies the content for our principles.  We cannot escape our history because it makes us who we are.