1. TANSTAAFL: There ain’t no such thing as a free lunch.

2. Incentives matter; incentives affect behavior.

3. Economic thinking is thinking on the margin.

4. The only way to create wealth is to move resources from a lower-valued to a higher-valued use. Corollary: Both sides gain from exchange.

5. Information is valuable and costly, and most information that’s valuable is inherently decentralized.

6. Every action has unintended consequences; you can never do only one thing.

7. The value of a good or a service is subjective.

8. Creating jobs is not the same as creating wealth.

9. The only way to increase a nation’s real income is to increase its real output.

10. Competition is a hardy weed, not a delicate flower.

Numbers 4 and 9 are core elements of Say’s Law.