A classic rhetorical question is “If we can put a man on the moon, why can’t we end poverty?” Russ Roberts attempts to answer.

Putting a man on the moon is an engineering problem. It yields to a sufficient application of reason and resources. Eliminating poverty is an economic problem (and by the word “economic” I do not mean financial or related to money), a challenge that involves emergent results. In such a setting, money alone—in the amounts that a non-economic approach might suggest, one that ignores the impact of incentives and markets—is unlikely to be successful.

To really get what he is saying, you have to read the entire essay, which I strongly recommend. The key point is that economic processes emerge out of the decentralized actions of many individuals, while engineered processes are centrally designed.