Hypotheses can be confirmed in this manner by experimental test. For example, drawings of rotated corners have asymmetrical junctions. The asymmetry might be responsible for the decreased illusion. With many such empirical tests, the weight of evidence may converge in support of a single explanation. The human perceptual system works under a set of assumptions and when these assumptions are violated it may malfunction to produce illusions.
Illusions provide dramatic clues as to the nature of the underlying assumptions.
Hypotheses can be formulated and predictions tested empirically. Hypotheses can also be tested by computer emulation . Sensation and Perception , 3rd Ed. Harcourt Brace Jovanovich. The psychology of perspective and Renaissance art .