Buy not on optimism, but on arithmetic.
Confronted with a challenge to distill the secret of sound investment into three words, we venture the motto, Margin of Safety.
Investing is most intelligent when it is most businesslike.
At heart, "uncertainty" and "investing" are synonyms.
An investment operation is one which, upon thorough analysis, promises safety of principal and an adequate return.
You must never delude yourself into thinking that you're investing when you're speculating.