Adam Smith's "invisible hand" in context

Princeton University economics professor Alan Blinder puts Adam Smith's concept of the "invisible hand" in context:

When economists first heard Gekko's now-famous dictum, "Greed is good," they thought it a crude expression of Adam Smith's "Invisible Hand"—which is one of history's great ideas. But in Smith's vision, greed is socially beneficial only when properly harnessed and channeled. The necessary conditions include, among other things: appropriate incentives (for risk taking, etc.), effective competition, safeguards against exploitation of what economists call "asymmetric information" (as when a deceitful seller unloads junk on an unsuspecting buyer), regulators to enforce the rules and keep participants honest, and—when relevant—protection of taxpayers against pilferage or malfeasance by others. When these conditions fail to hold, greed is not good.

Greed is a natural human vice, just like aggression. As much as we may try, we cannot get rid of them because they are part of human nature. But just as sport channels aggression into productive use, free enterprise does the same for greed. Free enterprise is only productive when its goal is to benefit consumers. When it becomes acceptable to screw consumers (or taxpayers) in the quest for wealth, the benefit is entirely lost.

Greed is not good. It is the productive work and investment we do as a result of our greed that is good.