In 1873, the U.S. Congress passed the Timber Culture Act, granting up to 160 acres to any head of a family willing to plant and keep 40 acres of trees in the Great Plains for a period of 10 years. But when would-be settlers attempted to go into the timber business, they ran into a problem that is obvious to any modern person—without a huge supply of water, you can’t just drop a forest in the middle of a dry prairie.
Were 19th-century farmers idiots? No, but they were confused. The idea that you could plant timber out on the prairies was predicated on the theory that “rainfall follows the plow”—a now-discredited notion that if you break up the prairie sod with a plow, the soil will get better at absorbing rainfall, and will slowly release the water back into the atmosphere, increasing future rainfall. If you plant it, rain will come.
If you were on the Great Plains in the 19th century, it’d be valuable to know that plowing the soil won’t inevitably summon up a good climate. Just so, if you’re on Mars in the 21st century, it’d be valuable to know that a harsh environment and great distance from Earth won’t inevitably summon up a good political climate.
Yet, advocates for space settlement persist in pushing theories of the American West founded more in myth than history. Chief among them is the so-called Turner thesis—a grand theory of the American West that has been out of the academic mainstream for decades.
The Turner thesis begins with an 1893 speech by a young historian named Frederick Jackson Turner about the nature of the American frontier, laying out ideas that he continued to develop over the course of a rise to nationwide fame.
Here’s the basic idea: The American frontier was a line of expansion ever-moving westward, where European men could get access to cheap land. By claiming and taming that land, and by organizing to fight its former inhabitants, they gained a number of…