The worst sort of business is one that grows rapidly, requires significant capital to engender the growth, and then earns little or no money. Think airlines. Here a durable competitive advantage has proven elusive ever since the days of the Wright Brothers. Indeed, if a farsighted capitalist had been present at Kitty Hawk, he would have done his successors a huge favor by shooting Orville down.

So if you are evaluating others (or yourself!) in the investment field, think out some standards - apply them - interpret them.

We've got more productive capacity now than we ever have.

There is no perfect mathematical formula for pricing a business.

You are neither right nor wrong because the crowd disagrees with you.

It is obvious that the performance of a stock last year or last month is no reason, per se, to either own it or to not own it now. It is obvious that an inability to "get even" in a security that has declined is of no importance. It is obvious that the inner warm glow that results from having held a winner last year is of no importance in making a decision as to whether it belongs in an optimum portfolio this year.

What the wise do in the beginning, fools do in the end.