The early 1900s was an amazing time for Western science, as Albert Einstein was developing his theories of relativity and psychology was born, as Sigmund Freud and psychoanalysis took over the scientific mainstream. Karl Popper observed these developments firsthand and came to draw a distinction between what he referred to as science and pseudoscience, which might best be summarized as science disconfirms, while pseudoscience confirms. While the way we describe these disciplines has changed in the intervening years, Popper’s ideas speak to the heart of how we arrive at knowledge.