Wall Street has come a long way from the insider-dominated world that was blown apart by the Great Depression.

Unfortunately, there is something of a flaw in this idealized picture of the way the scientific community discovers truth. And the flaw is that most scientific work never gets noticed. Study after study has shown that most scientific papers are read by almost no one, while a small number of papers are read by many people.

When all is said and done, cheap gas is an illusion, because our reliance on gas creates a whole series of costs that aren't factored in to the pump price - among them congestion, pollution, and increased risk of accidents.

The oil market is especially sensitive even to a hint of expansion or contraction in supply.

Medical tourism can be considered a kind of import: instead of the product coming to the consumer, as it does with cars or sneakers, the consumer is going to the product.

Lower oil prices won't, by themselves, topple the mullahs in Iran. But it's significant that, historically, when oil prices have been low, Iranian reformers have been ascendant and radicals relatively subdued, and vice versa when prices have been high.

The fact that industries wax and wane is a reality of any economic system that wants to remain dynamic and responsive to people's changing tastes.