Zero-sum: It’s thinking that if you have more, I have less. One more baby in a family is one more mouth to feed, and less food for everyone else. One new business opens up on the block, and all the rest of the businesses suffer. The guy in the cubicle next to you gets a raise, and you get nothing, because there’s nothing left.

Except that it’s wrong. Lots of people know it, too. P.J. O’Rourke knows it, and he wants to make it clear to President Obama as well. O’Rourke congratulates Obama for some things here at the end of 2012, such as taking care of Osama bin Laden and for not being Jimmy Carter. However, O’Rourke also schools Obama on the fallacy of zero-sum thinking:

You sent a message to America in your re-election campaign. Therefore you sent a message to the world. The message is that we live in a zero-sum universe.

There is a fixed amount of good things. Life is a pizza. If some people have too many slices, other people have to eat the pizza box. You had no answer to Mitt Romney’s argument for more pizza parlors baking more pizzas. The solution to our problems, you said, is redistribution of the pizzas we’ve got—with low-cost, government-subsidized pepperoni somehow materializing as the result of higher taxes on pizza-parlor owners.

In this zero-sum universe there is only so much happiness. The idea is that if we wipe the smile off the faces of people with prosperous businesses and successful careers, that will make the rest of us grin.

There is only so much money. The people who have money are hogging it. The way for the rest of us to get money is to turn the hogs into bacon.

Mr. President, your entire campaign platform was redistribution. Take from the rich and give to the . . . Well, actually, you didn’t mention the poor. What you talked and talked about was the middle class, something most well-off Americans consider themselves to be members of. So your plan is to take from the more rich and the more or less rich and give to the less rich, more or less. It is as if Robin Hood stole treasure from the Sheriff of Nottingham and bestowed it on the Deputy Sheriff.

But never mind. The evil of zero-sum thinking and redistributive politics has nothing to do with which things are taken or to whom those things are given or what the sum of zero things is supposed to be. The evil lies in denying people the right, the means, and, indeed, the duty to make more things.

Let’s hope President Obama gets this economic lesson right. There’s money to be made, businesses to be built and jobs to be created. We don’t have to have skinnier slices of pizza; we can make more.

Read “Dear Mr. President, Zero-Sum Doesn’t Add Up” in the Wall Street Journal.