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.
Thus the first and most important stratagem adopted to cheapen construction was the squaring and turning of components in order to eliminate offering up and individual fitting. The flatness, straightness, and squareness which more than any other characteristic distinguish man's construction from the works of God, derive from economy. We see the mark of economy in every building of squared masonry however magnificent it may be. Only the few remnants of ancient polygonal masonry remind us that the pattern of stone work where each stone is individually fitted can be very different from the cheap squared pattern to which we are accustomed."