The primary thing when you take a sword in your hands is your intention to cut the enemy, whatever the means. Whenever you parry, hit, spring, strike or touch the enemy’s cutting sword, you must cut the enemy in the same movement. It is essential to attain this. If you think only of hitting, springing, striking or touching the enemy, you will not be able actually to cut him.
The McNamara fallacy, named for Robert McNamara, the US Secretary of Defense from 1961 to 1968, involves making a decision based solely on quantitative observations (or metrics) and ignoring all others. The reason given is often that these other observations cannot be proven.
The fallacy refers to McNamara's belief as to what led the United States to defeat in the Vietnam War—specifically, his quantification of success in the war (e.g., in terms of enemy body count), ignoring other variables.
it is apparent that the unfolding of the design process assumed a distinctly episodic structure, which we might characterize as a series of related skirmishes with various aspects of the problem at hand.
As the scope of the problem became more determined and finite for the designer, the episodic character of the process seems to have become less pronounced. During this period a systematic working out of issues and conditions took hold within the framework that had been established. This phenomenon is not at all surprising when we consider the fundamental difference between moments of problem solving when matters are poorly defined and those with clarity and sufficiency of structure.
Within the episodic structure of the process, the problem, as perceived by the designer, tends to fluctuate from being rather nebulous to being more specific and well-defined. Furthermore, moments of "blinding" followed by periods of backtracking take place, where blinding refers to conditions in which obvious connections between various considerations of importance go unrecognized by a designer.