The search for the causes of events and the comparison of means with ends must always go hand in hand in the critical review of an act, for the investigation of causes leads us first to the discovery of those things which are worth examining.
This following of the clue up and down is attended with considerable difficulty, for the farther from an event the cause lies which we are looking for, the greater must be the number of other causes which must at the same time be kept in view and allowed for in reference to the share which they have in the course of events, and then eliminated, because the higher the importance of a fact the greater will be the number of separate forces and circumstances by which it is conditioned. If we have unravelled the causes of a battle being lost, we have certainly also ascertained a part of the causes of the consequences which this defeat has upon the whole War, but only a part, because the effects of other causes, more or less according to circumstances, will flow into the final result.
The same multiplicity of circumstances is presented also in the examination of the means the higher our point of view, for the higher the object is situated, the greater must be the number of means employed to reach it. The ultimate object of the War is the object aimed at by all the Armies simultaneously, and it is therefore necessary that the consideration should embrace all that each has done or could have done.
It is obvious that this may sometimes lead to a wide field of inquiry, in which it is easy to wander and lose the way, and in which this difficulty prevails—that a number of assumptions or suppositions must be made about a variety of things which do not actually appear, but which in all probability did take place, and therefore cannot possibly be left out of consideration.