Put a number on restraint and it becomes a target; put a target on it and the number stops meaning what it meant. We describe the departure from the model as an error. We might equally describe the model as a hopeful guess about us. Understanding people turns out to be a more urgent task than changing them, and a great deal harder. It is tempting to call this irrational. It is more useful to ask what it is for.
What follows
Notice how rarely anyone is argued out of the receipt, and how often they are simply moved past it by a change in circumstance. Every one of us runs the same shortcut, and every one of us believes we are the exception. The usual story is that we are careless calculators. The better story is that we are careful about the wrong things. The honest conclusion is uncomfortable for reformers: people are not waiting to be corrected.
