The aim of economics, therefore, is to teach men how to act "economically ". The economic mind deliberates upon relative values, adapts means to ends, and secures most valuable ends at least cost. Economic methods can be applied to any ends, whether in the realm of art, of religion, of politics, or of production. Economics can be applied to play as well as to work, to leisure as well as to production, to public as well as to private objectives, to war as well as to peace. For this school of thought the "economic" causes of war would be the circumstances which justified a calculation that in a given country in a given situation resort to war would be the cheapest means for accomplishing an end which its population considered of preeminent value. As the costs of war increase and cheaper means become available for achieving important public ends, war will become less and less "economic" in the sense of this theory. War would tend not to have economic causes and to arise only because of the frequent disposition of men not to calculate and not to manage their affairs "economically".