In On War, chapter one, section 28, Carl von Clausewitz speaks of a "wonderful trinity" composed of (1) violence, hatred, and animosity, (2) the play of probabilities and chance, and (3) the subordinate nature of a political instrument. These could be called, for short, (1) blind instinct, (2) free activity of the soul, and (3) an exercise of reason. He continues:

        These three tendencies, which appear like so many different lawgivers, are deeply rooted in the nature of the subject, and at the same time variable in degree. A theory which would leave any one of them out of account, or set up any arbitrary relation between them, would immediately become involved in such a contradiction with the reality, that it might be regarded as destroyed at once by that alone.

        The problem is, therefore, that theory shall keep itself poised in a manner between these three tendencies, as between three points of attraction.

        The way in which alone this difficult problem can be solved we shall examine in the book on the "Theory of War."

These three components are all classes of causal factors that drive the system called war. They act as "points of attraction" as magnets would operate on an iron pendulum. Clausewitz does not promise to solve the mathematical three-body problem that his analogy sets up. He says that the problem is that there are these three interacting attractors and any theory of war that is set up must be able to deal with the problematical (nonlinear, in fact) nature of the phenomenon called war.