From the standpoint of the exercise of judgment, it is a principle that the due determination of effects to be produced depends on the proper consideration of pertinent factors. Once the principles applicable to any subject have been formulated in necessary detail, the evaluation of the cited factors with respect to a particular situation becomes the vital procedure as to any problem where that subject is involved. In the course of this evaluation, corollary or subordinate principles may be of assistance (page 22). In military problems, however, the evaluation usually involves many factors not susceptible of reasonably exact determination by the use of formulae (see page 23). In such cases, experience, education, and training afford the only secure basis for judgment which will produce reliable conclusions. The principles, therefore, provide reliable guides by citing the factors to be evaluated in order to arrive at desired results, but the principles cannot replace logical thought in the evaluation of the factors. In formulating principles (see also page 23) as practical guides for action, as well as in using them when formulated, failure to give consideration to all pertinent factors may result in vitiating the effort based on their application. Danger also lies in the fact that any particular factor will infrequently have the same value--the same influence on the situation--in any two problems (page 25). Therefore, in each situation, each factor requires to be weighed in connection with the others. The soundness of the resulting conclusion will depend on the extent of the knowledge available (page 2) and on its useful employment. Summary of Fundamental Considerations. The factors (page 25) involved in determining the nature of an effect and of the action to attain it become fundamental considerations (page 25) when it is desired to arrive at such a result under a particular set of circumstances. The relationships obtaining between the desired effect and the action to attain it, on the one hand, and the factors involved, on the other, are best expressed in the form of principles. The next chapter is therefore devoted to the development of basic principles applicable to military problems. CHAPTER III BASIC PRINCIPLES APPLICABLE TO MILITARY PROBLEMS (The Fundamental Military Principle) On the basis of the previous discussion as to the natural mental processes and as to principles useful in their employment, Chapter III discusses the requirements for the attainment of an end in human affairs. The fundamental principle thus derived is then applied to the needs of the military profession, so as to develop the Fundamental Military Principle. This Principle indicates the requirements of a correct military objective and of the action for its attainment.