All decisions originate in the brain. So if we can better understand what's happening in the brain when we make investment decisions, maybe one day we'll be able to make more accurate financial forecasts - for a stock or even the entire market.

The oldest and most important currency is debt.

We are privileged that the dollar is the "currency of last resort" and the most important currency in the world. Global commodities are priced in dollars. Central banks in other countries hold great quantities of dollars. The dollar was the safe harbor, the port in the storm during the credit crisis.

For the last several decades, there was a prevailing belief among traditional economists that the markets were rational and self-correcting. Alan Greenspan advocated this view. But the 2008 financial crisis showed that this view is incorrect, and Greenspan eventually admitted as much.

Money is becoming increasingly plastic and digital. If there is a major disaster, let's say an asteroid strike, we'll go back to trading meats and furs. We won't need an abstraction, a dollar bill, but real tangible goods to survive.

In some cultures, when you give someone a gift, it's expected that they will pass it on. This seems like a peculiar practice in the West, but in many other societies, a gift has a spirit. If you try to possess the gift, you remove its spirit as a gift.

Researchers have found that identical twins who have been separated for long periods of time actually invest in a similar manner. Biology really does affect how we spend money.