Kepler's laws of planetary motion
Popper's prime example, already made by the French classical physicist and philosopher of science Pierre Duhem decades earlier, was Kepler's laws of planetary motion, long famed to be, and yet not actually, reducible to Newton's law of universal gravitation. For Feyerabend, the sham of inductivism was pivotal. Feyerabend investigated, eventually concluding that even in the natural sciences, the unifying method is "Anything goes"—often rhetoric, circular argumentation, propaganda, and even subterfuge—methodological lawlessness, "scientific anarchy". At persistent claims that faith in induction is a necessary precondition of reason, Feyerabend's 1987 book sardonically bids "Farewell to Reason".