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.
What keeps me busy in my classes is trying to help my students learn how to think. They say, "Rob holds his hands like this...," and they don't know that the reason I hold my hands like this is not to make myself look that way. The end result is not to hold the gun that way; holding the gun that way is the end result of doing something else.
…The more general issue is that a person who doesn't understand the thing they're trying to copy will end up copying unimportant superficial aspects of what somebody else is doing and miss the fundamentals that drive the superficial aspects. This even happens when there are very detailed instructions. Although watching what other people do can accelerate learning, especially for beginners who have no idea what to do, there isn't a shortcut to understanding something deeply enough to facilitate doing it well that can be summed up in simple rules, like "omit needless words".