The vastness of the issue decided by war, the fact that from its decision there is no appeal, the greatness of the forces that nations can produce, the length of experience of war extending through 8,000 wars, and during more than three thousand years of recorded history, the enormous literature of the subject, and the fact that more brain power, energy, and character have been devoted to war than to any other fruit of man's endeavor--combine to give to the conduct of war an importance that no other subject can possess. The thing that each side brings forward against the other side is force; "that which moves or tends to move matter." In all ages, it has been directed primarily against the physical bodies of individual men, threatening each individual man with suffering and death. It appeals to the primal instinct of men, self-preservation, and is the _ultima ratio regum_, the last argument of kings--and not only of kings, but of all other living things as well. The first feeling aroused by the threat against life, or physical well-being, is fear; and, therefore, the first force with which to oppose the threat is a force of the same spiritual nature as fear, but opposite in direction. This force is called in the English language "courage." Without courage every man and every nation would be at the mercy of every man or nation that made a threat against it. The inherent necessity for courage is thus apparent; and the reason is therefore apparent, for the fact that in every nation and tribe physical courage has been esteemed the greatest virtue in a man. In Latin, we know, the word _virtus_ meant courage, and also virtue--showing that the Romans held the two qualities to be identical or similar. In discussing the operations of war, little is usually said of courage. The reason, however, is not that its value is unrecognized, but that its existence is assumed; in the same way as that in which all the other faculties among the men are assumed, such as physical health, ability to march, etc. Movements to inspire fear, however, actions to break down the morale, are of frequent use; because, if the morale of the opposing side is broken down, its power of resistance is destroyed. In the operations, therefore, of two contending parties, force is opposed by force. If the forces on both sides could be concentrated at a single point, and exerted in opposite directions, the result would be decided in an instant. Such an arrangement has never yet been brought about; though fairly close approximations have been made, when two parties have selected two champions who have fought for them--the victory going by agreement to the side whose champion became the victor.