Investing is the intersection of economics and psychology. The analysis is actually the easy part. The economics, the valuation of the business isn't that hard. The psychology - how much do you buy, do you buy it at this price, do you wait for a lower price, what do you do when it looks like the world might end - those things are harder. Knowing whether you stand there, buy more, or whether something has legitimately gone wrong and you need to sell, those are harder things. That you learn with experience, by having the right psychological makeup.

There are only a few things investors can do to counteract risk: diversify adequately, hedge when appropriate, and invest with a margin of safety. It is a precisely because we do not and cannot know all the risks of an investment that we strive to invest at a discount. The bargain element helps to provide a cushion for when things go wrong.

Pressure to produce over the short term - a gun to the head of everyone - encourages excessive risk taking which manifests itself in several ways - fully invested posture at all times, the use of leverage, and a market centric orientation that makes it difficult to stand apart from the crowd and take a long term perspective.

Investors should always keep in mind that the most important metric is not the returns achieved but the returns weighed against the risks incurred. Ultimately, nothing should be more important to investors than the ability to sleep soundly at night.

The government - the ultimate short-term-oriented player - cannot withstand much pain in the economy or the financial markets. Bailouts and rescues are likely to occur, though not with sufficient predictability for investors to comfortably take advantage. The government will take enormous risks in such interventions, especially if the expenses can be conveniently deferred to the future. Some of the price-tag is in the form of back- stops and guarantees, whose cost is almost impossible to determine.

It sounds kind of crazy, but in times of turmoil in the market, I've felt a sort of serenity in knowing that I've checked and re-checked my work, one plus one still equals two regardless of where a stock trades right after I buy it.

I think markets will never be efficient because of human nature.