Max Wertheimer

Czech-German psychologist who co-founded the Gestalt school of psychology by demonstrating that perception of motion (the phi phenomenon) cannot be explained by summation of individual sensory elements.

Demonstrated through the phi phenomenon that the whole of perceptual experience is irreducibly different from the sum of its parts — founding Gestalt psychology as a systematic challenge to Wundt's elementist psychology and Behaviorism's stimulus-response atomism.