[mnmalst]

That's interesting, so how can people like that know which is real and which is not? I don't understand it.

[altruios]

Try the crossed eyes 'find the difference' technique. Which is crossing your eyes such that a third image (a blending of the two images: one from each eye) appears between those two images.

https://www.youtube.com/watch?v=qvdVBzuGWr4

You can easily understand where the difference is because the data is different between the eyes. The difference appears 'ghostly'. In a similar way, data from the mind's eye is different from data from the physical eyes when those two 'streams of data' are blended.

[mnmalst]

Yes I can do this. I can see the image in the middle the same way as I see each individual image. (But not both at the same time, the outside images get blurry when I focus on the one in the middle).

Anyways, this is nothing like what I experience when I imagine something.

[swat535]

I can do this, the best I can describe it is that your brain "knows" you're imagining it so it's different than for example hallucinations.

It's similar to replaying music in your head (if you can do that), you can hear the tune but your ears "know" no music is actually playing.