If Christmas is (alas) a time for a materialist blowout, January is often a time for rueful reflection. Should we really have bought all that soon-to-be-landfill for each other? The answer, as I have written a dozen times, is . . . probably not.
Thankfully, people have stopped sending me emails declaring that economists don’t understand Christmas. Now they are sending me emails declaring that economists don’t understand exponential growth, and that as a result, the planet is doomed. This grates, because saying that economists don’t understand exponential growth is like saying that accountants don’t understand double-entry book-keeping, or that poets don’t understand metaphor. Consider the bait taken.
An old illustration of exponential growth remains the best. Legend has it that the genius who invented chess was asked to name his reward by a delighted monarch, and requested a modest-sounding payment: one grain of rice for the first square of the chessboard, two for the second, four for the third . . . doubling each time. This doubling is an exponential process, and most people are surprised when they first hear that the 64th square would require more than any harvest could produce.