Direct experience is inherently too limited to form an adequate foundation either for theory or for application. At the best it produces an atmosphere that is of value in drying and hardening the structure of thought. The greater value of indirect experience lies in its greater variety and extent. History is universal experience, the experience not of another, but of many others under manifold conditions.

In should be the duty of every soldier to reflect on the experiences of the past, in the endeavor to discover improvements, in his particular sphere of action, which are practicable in the immediate future.

The blurring of the line between policy and strategy] encouraged soldiers to make the preposterous claim that policy should be subservient to their conduct of operations, and (especially in democratic countries) it drew the statesman on to overstep the definite border of his sphere and interfere with his military employees in the actual use of their tools.

For the spread and endurance of an idea the originator is dependent on the self-development of the receivers and transmitters.

I used to think that the causes of war were predominantly economic. I came to think that they were more psychological. I am now coming to think that they are decisively "personal," arising from the defects and ambitions of those who have the power to influence the currents of nations.

If we clear the air of the fog of catchwords which surround the conduct of war, and grasp that in the human will lies the source and mainspring of all conflict, as of all other activities of man's life, it becomes clear that our object in war can only be attained by the subjugation of the opposing will. All acts, such as defeat in the field, propaganda, blockade, diplomacy, or attack on the centres of government and population, are seen to be but means to that end.

In war, the chief incalculable is the human will.