Mathematics is ordinarily considered as producing precise and dependable results; but in the stock market the more elaborate and abstruse the mathematics the more uncertain and speculative are the conclusions we draw there from. Whenever calculus is brought in, or higher algebra, you could take it as a warning that the operator was trying to substitute theory for experience, and usually also to give to speculation the deceptive guise of investment.
Benjamin GrahamNo matter how careful you are, the one risk no investor can ever eliminate is the risk of being wrong. Only by insisting on what Graham called the "margin of safety" - never overpaying, no matter how exciting an investment seems to be - can you minimize your odds of error.
Benjamin GrahamThe most striking thing about Graham's discussion of how to allocate your assets between stocks and bonds is that he never mentions the word "age".
Benjamin GrahamTo enjoy a reasonable chance for continued better than average results, the investor must follow policies which are (1) inherently sound and promising, and (2) not popular on Wall Street.
Benjamin GrahamEven 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.
Benjamin Graham