Ignoring unintended consequences (and inevitable trade-offs) of actions is one of the most common ways in which a well meaning program can actually do harm. Some other common fallacies are:
- The nirvana fallacy - in which a system like capitalism is contrasted with an unrealizable ideal rather than with its historical or actual alternatives.
- False extrapolations - such as the claim that human population will increase exponentially and without end, thereby exhausting the earth’s resources.
- Assuming that “rich” and “poor” are static categories rather than categories through which many individuals pass during their lifetimes.
- The zero-sum game fallacy - in which a dollar gained in one place means a dollar must be lost someplace else.
- The many-headed materialist fallacy - in which trade never involves the creation of wealth, but is merely the exchange of some pre-existing material resource.
Each of these mistakes is easy enough to see through in the abstract, but also easy to forget in practice. Remember them, however, and you’ll be immunized against a lot of economic misinformation, even if you never take a course on economics. More importantly, you’ll be much more likely to advocate policies that not only have good purposes, but also good results.