The author's newborn twins interpret the classic faces-vase illusion, March 1996.
Akiyoshi Kitaoka is a psychology profesor at Ritsumeikan University in Kyoto. His site Akiyoshi's Illusion pages contains static works that generate "anomalous motion," including his famous Rotating Snakes. Kitaoka warns that illusions "might make sensitive observers dizzy or sick."
Edward H. Adelson is a Professor of Vision Science in the Department of Brain and Cognitive Sciences at MIT.
Michael Bach is a profesor of Opthamology at the University of Freiberg. His award winning site, 70 Optical Illusions and Visual Phenomena seems to be the best single introduction to visual illusions on the web. It receives an enormous amount of daily traffic. Most of the demonstrations are interactive animations.
Although we can be fooled by our senses, they serve us very well.. Pragmatist philosopher, Reuben Abel points to a loose fit between mind and a very real world:
T]he road that leads from my sense perceptions to my knowledge of the world outside myself is full of gaps, brambles and obscurities. But it is the only road I have; if I refused to travel on it because of its risks, I would not ever get outside of me. It is true that inference to the independent existence of external objects cannot be demonstrated. Russell says flatly, "Belief in the existence of things outside my own biography... must be regarded as a prejudice." But our justification of such a belief is pragmatic: we survive and act successfully in the world by assuming it.
Abel, Reuben (1976) Man is the Measure. The Free Press, New York.
Unbelievable as it seems, the checker squares A and B are exactly the same shade of grey!
optical illusions are artificial, contrived viewing situations. They pinpoint particular, stereotyped, genetically hard-wired aspects of a visual system that works extremely well.
Friedrich, Caspar David (1818) Wanderer above the Sea of Fog. Oil on canvas, Hamburger Kunsthalle, Hamburg.