Why bubbles are structurally likely

Grasping Reality with Both Hands: "Sixth, the market will go wrong whenever its prices function as forecasting mechanisms. A proper forecasting mechanism would weigh each individual's opinion by the precision of his or her knowledge. A market tends on the contrary to weigh each individual's opinion by his or her wealth. This means that whenever economic processes tend to revert to seem average level that the market is likely to get things wrong, for when prices rise above average those who are optimistic become richer and their opinions carry more weight and so prices tend to rise further above their likely long-run fundamental values. Bubbles and crashes, manias and panics, are thus built into the system.