A friend asks, is the wheel irreducibly complex?:
The wagon—and the wagon wheel—could not have been put together in stages. Either it works, or it doesn’t. And it enabled humans to spread rapidly into huge parts of the world.
The oldest axle ever discovered is not on a wagon or cart, but instead on a potter’s wheel in Mesopotamia. These may seem like simple machines, but they’re the first evidence that anyone anywhere recognized the center of a spinning disk is stationary and used it to their mechanical advantage. It’s a completely ingenious observation and so novel that it’s unclear where the idea came from—perhaps from a bead spinning on string?—as it has no obvious corollary in nature. The pole is called an axle, and many scholars consider it the greatest mechanical insight in the history of humankind.
Yet there exists another great intellectual leap between the potter’s wheel and a set of wheels on a rolling object. The full wheel set appears to have first been invented by a mother or father potter, because the world’s oldest axles are made of clay, are about two inches long, and sit beneath rolling animal figurines.Cody Cassidy, “Who Invented the Wheel? And How Did They Do It?” at Wired
Apparently, the oldest wheel found so far was a toy.
See also: The real reason why only human beings speak. Language is a tool for abstract thinking—a necessary tool for abstraction—and humans are the only animals who think abstractly