The principle: ""EVERY TIME YOU ACT, YOU ADD STRENGTH TO THE MOTIVATING IDEA BEHIND WHAT YOU HAVE DONE."" Which, in fact, is not unreasonable. Nor is the rest of this, the first self-helper we've read in a long time that uses the English language (as opposed to jargon) in a conventional way. No charts, no diagrams, no tricks. Just a simple, straightforward assessment of the effects on the average human of such things as habits, traumas, the need to be liked--or dealing with infuriating people. ""Beware of anyone who is enticing you to act in an unaccustomed mode,"" counsels Weinberg apropos of the infuriating. ""Be sure of the effects on you of the new mode, by being sure of the motives it will be honoring."" It ain't Plato, but it's better than some.