Keep in mind the date. In 1877, Galton was in pursuit of a causal explanation and thought that regression to the mean was a causal process, like a law of physics. He was mistaken, but he was far from alone. Many people continue to make the same mistake to this day. For example, baseball experts always look for causal explanations for a player’s sophomore slump. “He’s gotten overconfident,” they complain, or “the other players have figured out his weaknesses.” They may be right, but the sophomore slump does not need a causal explanation. It will happen more often than not by the laws of chance
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