At the start of every class I teach, I give my students what I call “The Ten Pillars of Economic Wisdom.” These pillars, I tell them, are the basis for a huge percent of economic analysis and if they master them, they will have accomplished a lot. None of the pillars, of course, is original with me. What is original is my choice of these ten, as well as the way I state some of them.

Pillar #1 is “TANSTAAFL.” It stands for “There Ain’t No Such Thing As a Free Lunch.” Science fiction writer Robert Heinlein popularized the acronym in his novel The Moon is a Harsh Mistress. Of course, to be grammatically correct, it should be “TINSFAAFL”: There Is No Such Thing as a Free Lunch.” What follows is my exposition and application of this simple, but profound, insight.

There are two meanings of the expression. One is always true, while the other is usually true.

These are the opening 3 paragraphs of “TANSTAAFL, There Ain’t No Such Thing as a Free Lunch,” one of the Econlib Feature Articles for March. This one is by me.

In the piece, I apply the principle to individual decisions, including decisions about the use of time, and decisions by politicians. I highlight the heroic effort by PBS’s Jim Lehrer to get Obama and McCain to make tradeoffs in their policy positions. I also, as the last paragraph says, point out another meaning of the term TANSTAAFL that is also commonly used.