The document discusses how many widely held beliefs in economics and finance have been proven wrong over time. It provides examples of interest rates becoming negative, inflation being much lower than expected, and the price of oil fluctuating dramatically instead of steadily increasing. The author argues that one should be humble and flexible in their views instead of rigidly holding positions, as the financial world is always changing in ways that may contradict current assumptions. Staying open-minded and avoiding extreme portfolio positions based on specific worldviews can help investors adapt to changes.