The first thought which naturally occurs to one who accepts this view is that it would be well if men were more under the dominion of reason. War, to those who see that it must necessarily do untold harm to all the combatants, seems a mere madness, a collective insanity in which all that has been known in time of peace is forgotten. If impulses were more controlled, if thought were less dominated by passion, men would guard their minds against the approaches of war fever, and disputes would be adjusted amicably. This is true, but it is not by itself sufficient. It is only those in whom the desire to think truly is itself a passion who will find this desire adequate to control the passions of war. Only passion can control passion, and only a contrary impulse or desire can check impulse. Reason, as it is preached by traditional moralists, is too negative, too little living, to make a good life. It is not by reason alone that wars can be prevented, but by a positive life of impulses and passions antagonistic to those that lead to war. It is the life of impulse that needs to be changed, not only the life of conscious thought. All human activity springs from two sources: impulse and desire. The part played by desire has always been sufficiently recognized. When men find themselves not fully contented, and not able instantly to procure what will cause content, imagination brings before their minds the thought of things which they believe would make them happy. All desire involves an interval of time between the consciousness of a need and the opportunity for satisfying it. The acts inspired by desire may be in themselves painful, the time before satisfaction can be achieved may be very long, the object desired may be something outside our own lives, and even after our own death. Will, as a directing force, consists mainly in following desires for more or less distant objects, in spite of the painfulness of the acts involved and the solicitations of incompatible but more immediate desires and impulses. All this is familiar, and political philosophy hitherto has been almost entirely based upon desire as the source of human actions. But desire governs no more than a part of human activity, and that not the most important but only the more conscious, explicit, and civilized part.