The human brain is capable of registering “X is moving” without being able to point to “X was over here and is now over there”. This can happen visually with the rotating snakes illusion, or acoustically with Shepard tones, for instance. It’s also pretty common on some psychedelic drugs.
Or if your inner ear is messed up somehow by illness, drunkenness, etc. (though what you then think is moving is yourself, or perhaps the rest of the universe around you).
Well, the rotating snakes have a lot of element that breaks the symmetry. But if you stare at a perfectly blank disk it’s impossible to tell if it’s moving or not.
I didn’t mean to suggest that exactly the same thing was going on; just that it was analogous: it’s possible to have the perception of motion without there being any motion going on. There’s no consistency checker in the human perceptual system to keep that from happening.
I suspect that’s why optical illusions are so fascinating to some of us — they demonstrate that our perceptions don’t implement the law of non-contradiction. The snakes illusion is just a quick way to demonstrate this in humans who aren’t in a religious ecstasy or on psychedelics.
The human brain is capable of registering “X is moving” without being able to point to “X was over here and is now over there”. This can happen visually with the rotating snakes illusion, or acoustically with Shepard tones, for instance. It’s also pretty common on some psychedelic drugs.
Or if your inner ear is messed up somehow by illness, drunkenness, etc. (though what you then think is moving is yourself, or perhaps the rest of the universe around you).
Well, the rotating snakes have a lot of element that breaks the symmetry. But if you stare at a perfectly blank disk it’s impossible to tell if it’s moving or not.
I didn’t mean to suggest that exactly the same thing was going on; just that it was analogous: it’s possible to have the perception of motion without there being any motion going on. There’s no consistency checker in the human perceptual system to keep that from happening.
I suspect that’s why optical illusions are so fascinating to some of us — they demonstrate that our perceptions don’t implement the law of non-contradiction. The snakes illusion is just a quick way to demonstrate this in humans who aren’t in a religious ecstasy or on psychedelics.