It is rather easy to spot good companies through an examination of financial data, and to determine what the stock in those companies should be worth. An astute investor can apply superior insight to make big killings on mispriced stocks. Using his superior insight he will be able to take action long before other investors catch on. Studying past price movements is an aid to predicting future price movements. This skill can be applied to both individual stocks and the movement of the market as a whole.
Economic predictions are reliable, and form another strong foundation for success.
It is reasonably easy to select good advisors and managers, because their past track record is a reliable indicator of future success and skill. It doesn't do us any good to think of investing in these terms. In fact, it creates problems, and keeps us from enjoying the fruits of a game strongly tilted in our favor. From personal experience, I can tell you that it is very difficult to unlearn something you have always known. We tend to cling to those old familiar ways of thinking in most unreasonable ways.