War is an area of uncertainty; three quarters of the things on which all action in War is based on are lying in a fog of uncertainty to a greater or lesser extent. The first thing (needed) here is a fine, piercing mind, to feel out the truth with the measure of its judgment.
The great uncertainty of all data in war is a peculiar difficulty, because all action must, to a certain extent, be planned in a mere twilight, which in addition not infrequently — like the effect of a fog or moonlight — gives to things exaggerated dimensions and unnatural appearance.
- Carl von Clausewitz
