An illusion is a distortion of a sensory perception. Each of the human senses can be deceived by illusions, but visual illusions are the most well known. Illusions are subjective; different people may experience an illusion differently, or not at all.
- Optical illusions, such as mirages, exploit assumptions made by the human visual system.
- Auditory illusions, such as the Shepard Tone, exploit our hearing.
- Touch illusions exploit our sense of touch.
- Stage magic is a popular form of entertainment based on illusion. Magicians use tricks to give their audiences the impression that seemingly impossible events have occurred. See magic (illusion).
- simulated reality for a more radical approach to the possibility of illusion
- Hermann von Helmholtz