While many principles in economics textbooks are grossly oversimplified with children's-storybook examples, it is also true that they can clarify some of the fundamental economic relationships: e. g. stories about Robinson Crusoe and Man Friday, or about a person whose shopping list contains just the two items – apples and pears, or cummerbunds and kumquats. The trouble is, some people who learn their economics in an engaging scale-model landscape find it hard to leave it. The models of great beauty and complexity which they produce can confirm the richly-misleading potential of absurd assumptions.

Lean Logic, 1st ed. (2011), p. 488