a checklist that he routinely uses. Any other mode of operation will cause him

to miss much that is important.

 

Skills of a very high order can be maintained only with daily practice. The

pianist Paderewski once said that if he failed to practice for a single day, he

could notice his performance deterioration and that, after a week’s gap in

practice, the audience could notice it as well.

 

The hard rule of Use-It-or-Lose-It Tendency tempers its harshness for the

diligent. If a skill is raised to fluency, instead of merely being crammed in

briefly to enable one to pass some test, then the skill (1) will be lost more

slowly and (2) will come back faster when refreshed with new learning. These are

not minor advantages, and a wise man engaged in learning some important skill

will not stop until he is really fluent in it.

 

Twenty: Drug-Misinfluence Tendency

 

This tendency’s destructive power is so widely known to be intense, with

frequent tragic consequences for cognition and the outcome of life, that it

needs no discussion here to supplement that previously given under “Simple,

Pain-Avoiding Psychological Denial.”

 

Twenty-One: Senescence-Misinfluence Tendency

 

With advanced age, there comes a natural cognitive decay, differing among