When we speak of a man as skilled in any way, we do not mean that he knows the rules of doing something, but that he possesses the habit of doing it. Of course, it is true that knowing the rules, more or less explicitly, is a condition of getting the skill. You cannot follow rules you do not know.

The first is called the "learning plateau." During a series of days in which a performance, such as typewriting or receiving the Morse code telegraphically, is practiced, the curve shows improvement both in speed and in the reduction of errors. Then suddenly the curve flattens out. For some days, the learner cannot make any advances. His hard work seems to yield no substantial effects either in speed or accuracy. The rule that every bit of practice makes a little more perfect appears to break down. Then, just as suddenly, the learners gets off the plateau and starts to climb again.

But a practical problem can only be solved by action itself. ... The kind of practical judgment which immediately precedes action must be highly particular. It can be expressed in words, but it seldom is.