I don’t really know what it means to even imagine a color that I’ve seen before. I can’t really tell whether I’m really “imagining” it, or just “imagining that I’m imagining” it.
I can, for example, show you a color you’ve never seen before:
Stare at the white dot in the centre of the red circle. The longer – the better (two minutes and you’ll get a much stronger effect). Always try to keep focused on the white dot. It’ll be worth it.
Soon after staring, you’ll start to see a thin rim of light around the edge. Don’t stop staring though yet! Wait another minute – keeping your head perfectly still.
Once you’ve done this, slowly – move your head backwards – making sure to keep your eyes focused on the dot at all times. The circle’s rim will glow brilliantly with true Cyan! Keep on moving your head slowly backwards, and it’ll glow very hot!…
The blue/cyan colour chart to the right isn’t part of the illusion, but there to demonstrate that the ultra cyan you have just seen is not in the monitor’s color palette! It should be, but isn’t.
It’s an amazing effect.
If you stare at the white dot long enough and follow the instructions, and you’ll see a shade of cyan that you’ve never seen. The experience doesn’t seem all that novel. It’s just a way of stimulating the existing nerves in a way that isn’t done under ordinary circumstances. Can you really “imagine” that color, any more, less, or differently than you would some other more standard color?
Seems to me that you get an equivalent answer from any new notion of circuitry designed to stimulate the visual centers in a novel way. I suspect that those who take certain drugs experience exactly that, and maybe they do or don’t see colors that they didn’t “imagine” before.
Overall, it just seems to me that without a more rigorous understanding of what it means to “imagine” something, the problem is more philosophical than scientific. Which is to say, it’s more monkeying about with semantics than objective discussion of what actually happens.
Courtesy : Quora