In the beginning, people didn’t know when they were looking at an optical illusion if their brain was playing tricks on them or if their eyes were playing tricks on them. A lot of people thought they could explain why we see optical illusions.

Epicharmus and Protagorus both lived around 450 B.C. Epicharmus believed that our senses (seeing, hearing, smelling, tasting and touching) were not paying enough attention and were messing up. His exact words were, "The mind sees and the mind hears. The rest is blind and deaf." Protagorus went against what Epicharmus said. He thought that our senses and body were just fine. He believed that it was the environment that was messing us up. He said, "Man is nothing but a bundle of sensations."

Aristotle, who lived around 350 B.C., said that Epicharmus and Protagorus were both right and wrong. He said our senses can be trusted, but they can be easily fooled. For example, when it’s a very hot day and you stand near the road, heat waves rise and we can see them. Our senses are right, we can see the waves. But, if you look through the waves at a tree, the tree appears to be wiggling. That is when our senses get fooled.

Another Greek was Plato. Plato lived around 300 B.C. He said that our five senses need our mind to help interpret what they see. In other words, the eyes and mind need to work together. That is exactly what we think now.

A long time passed until someone got into optical illusions again. In 1826, a psychologist Johannes Mueller wrote two books about visual illusions. But, few people knew what he was talking about because he was the first person to call distortions visual illusions. In 1854, another psychologist J.J. Oppel continued were Mueller left off. He published a paper with ten pages about line illusions. Nobody had ever seen the illusions he talked about. They were new like DVD players or a Ricky Martin song, and they got very popular. Almost everyone liked them, for awhile. Even the famous Mueller-Lyer illusion was introduced and twelve theories were made to explain the illusion.

But just like everything that is new, people get bored with it. Like when you want to throw your stereo out the window if they play an old song one more time. So, from 1912 to 1950 out of 4,250 articles in newspapers, journals and magazines, only 4 were about optical illusions.

Nobody knows why optical illusions became interesting again, but now we have lots of illusions of different types. As a matter of fact, we have tons of books on them and now, even several web pages of them. They entertain us, are used in art, music, jobs, and nature. Imagine what we’ll have in 100 years!