Your Teacher Said What?! by Joe Kernen

first locomotives across the English countryside, only about four thousand patents had been granted. That was enough, however, to ignite the Industrial Revolution, which would take the worldwide average GDP when Stewart Hartshorn was born in 1845—about $1,000 a year, still a considerable increase from the $700 to $800 at which it had been frozen for centuries—and more than double it by the time he died in 1935. 14
    Hartshorn’s invention wasn’t exactly the steam engine. When he was not yet twenty, he invented a mechanical window shade—or in the type of language beloved of patent lawyers, “the application of a pawl and ratchet or notched hub, arranged in such a manner that the shade may be stopped and retained at any desired height or point within the scope of its movement by a single manipulation of the shade, the usual cord for operating or turning the shade-roller being dispensed with entirely, as well as counterpoises, which had in some instances been employed, in connection with spring rollers, for holding the shade at the desired point.”
    The Hartshorn roller shade was successful enough that its design long survived the patent protection it was given in 1864; it was essentially the same design still in use when I was young enough to be scared out of my wits every time the roller pulled the window shade up with a sound like a gunshot. Hartshorn’s creation made him far wealthier than his career as a real estate developer. His experience was a small, though profitable, example of the “discovery” of a right to intellectual property, one that was unknown to Galileo or Leonardo or a thousand generations of anonymous innovators. All of them, you see, lived in a time when the only way to make a living as an inventor was to either find a rich patron or keep your invention secret, neither of which was an especially good incentive to treat inventions as property able to be bought and sold.
    Once inventions began to be treated as property, the same thing happened to them that happened to every other sort of property: When people can buy and sell ideas, they start producing more of them. A lot more. Hartshorn’s roller-shade patent was the 44,624th issued by the U.S. Patent and Trademark Office in the seventy-three years from its inception in 1789, almost immediately after the Constitution (which granted the national government a right to issue patents and copyrights) was ratified.
    This is one of the most counterintuitive things about property specifically and free markets generally. Every other competing economic system assumes that things of value are finite: that when you consume something, you leave behind less than when you started. But as mankind has found more and more ways to recognize property rights in goods, the opposite has happened. Once someone can own them, we get more trees, more crops—and more (and more valuable) ideas.
    Easy to see, when you think about it. Hard to explain, however, to a ten-year-old.

    â€œBlake, you know we use oil and coal and natural gas for energy, right?”
    â€œElectric cars don’t.”
    â€œEven electric cars need to get energy from power plants, and they burn coal and oil and gas.”
    â€œOkay.”
    â€œDo you know where we get the fuel from?”
    â€œThe ground?”
    â€œPretty much. Most of it has been in the ground for hundreds of millions of years, and it takes million of years to produce more.”
    â€œI know that.”
    â€œSo . . . when someone drills a hole in the surface of the earth and takes oil or coal out of it, is there more or less left behind?”
    â€œLess, of course.”
    â€œSo what would you say if I told you that we’ve been drilling for oil for a hundred years, and there’s a lot more oil now than there was a hundred years ago?”
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    Blake said nothing, though her expression told me she knew she was being tricked but didn’t know how. She has a