Both individual skill (art) and chance are important factors in determining success or failure.

We have been trying to point out that this concept of an indefinitely favorable future is dangerous, even if it is true; because even if it is true you can easily overvalue the security, since you make it worth anything you want it to be worth. Beyond this, it is particularly dangerous too, because sometimes your ideas of the future turn out to be wrong. Then you have paid an awful lot for a future that isn't there. Your position then is pretty bad.

Nothing important on Wall Street can be counted on to occur exactly in the same way as it happened before.

Even with a margin of safety in the investor's favor, an individual security may work out badly. For the margin guarantees only that he has a better chance for profit than for loss - not that loss is impossible. But as the number of such commitments is increased the more certain does it become that the aggregate of the profits will exceed the aggregate of the losses.

I am more and more impressed with the possibilities of history's repeating itself on many different counts. You don't get very far in Wall Street with the simple, convenient conclusion that a given level of prices is not too high.

To have a true investment, there must be a true margin of safety. And a true margin of safety is one that can be demonstrated by figures, by persuasive reasoning, and by reference to a body of actual experience.

There is no reason to feel any shame in hiring someone to pick stocks or mutual funds for you. But there's one responsibility that you must never delegate. You, and no one but you, must investigate whether an adviser is trustworthy and charges reasonable fees.