Karl Popper said a theory that can explain everything actually explains nothing

Popper noticed that theories like Freudian psychoanalysis seemed to fit every possible human behavior, and decided that was their weakness, not their strength: a claim that no observation could ever contradict isn't scientific at all. He proposed falsifiability — the requirement that a theory forbid some possible outcome — as the line separating genuine science from pseudoscience.

— Karl Popper, The Logic of Scientific Discovery — 1934 (English translation 1959)
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