By the way, in case you didn’t know already, Earl Nightengale beat you to your summary sentence of the Secret. I forget his actual wording, but it’s something like “you become what you think about most of the time.”

I’m generally in favor of people getting clear on their goals and creating written plans for their accomplishment. On the other hand, there are many examples of wealthy people, famous people, and other high achievers that did not utilize this strategy, and examples of people using this strategy that do not ultimately achieve very much. For example, my friend’s wealthy relatives do not have nor did they ever have written goals or plans to achieve them–they just somewhat ruthlessly and obsessively pursued the acquisition of wealth without much concern for others (not necessarily what I’d recommend, but it’s a counterexample).

Certainly a definiteness of purpose is critical for high achievement, if that’s your outcome.