Ah yes, this reminds me of "the brain in the vat" philosophical question posed in my 101 class.

Imagine you were unknowingly captured by s mad scientist, your brain was removed, then kept in a vat. The scientist hooked you up to a machine that stimulated your senses, fooling you into believing everything was A-OK.

All our senses are electrical and chemical impulses derived from external stimuli, so hypothetically your brain could be tricked into believing it was on a body. If the simulation was indistinguishable from reality, could you tell what is real or not?

The meat on the bones here is, can you prove that you are not currently trapped as a brain in a vat? Our brain and bodies interpret the external world in a very personal way. What I see as blue is not the same blue that you see, even though we can both accurately identify many shades of blue.

I've often wondered how the world would look or feel in someone else's body. Would the world suddenly look like a van Gogh or Picasso painting, maybe Escher? Would pain, excitement, or love feel the same in someone else's body?

Vanilla sky is another good movie on this topic. As Penelope Cruz said, "We will be together in the next life, when we are both cats."