OK, so suppose they've invented a teleportation device. It scans all the matter and energy in your body, vaporizes your body, and then reassembles all the matter and energy at your destination. The poll is, would you use this device, assuming there's no risk of malfunction? Some people think that the person who appears at your destination would just be a perfect clone of you, but it wouldn't actually be you. To me, it seems these people must be dualists-they think a person consists of something else besides matter and energy... perhaps a soul? I don't believe in souls, and I think that the only continuity between me now and me a minute ago is spatio-temporal and psychological. I see no reason for a spatio-temporal discontinuity to change my identity, and the teleporter will perfectly preserve psychological continuity. I believe it will feel like I step into the teleporter on Earth, and then instantly realize that I'm on Mars. Problems arise if you suppose that the teleporter malfunctions: it successfully copies you to your destination, but your original body is not destroyed. If you would have originally used the teleporter, you must have been willing to say that the person who stepped into the machine and the person who appeared at the destination were the same person. But, if they are the same person, who's this person that was supposed to be vaporized? Surely the fact that a vaporizer on Earth broke wouldn't change the identity of a person on Mars... But just as surely, the person who remains on Earth is the same person as the one who stepped into the teleporter; he stepped in, was scanned, and then nothing happened. Are there now two of you in existence? Do "you" experience both their consciousnesses? Who has the legal right to your property? Who gets to go home and sleep with your spouse? I find all these questions incredibly interesting (and revealing of one's metaphysical beliefs about consciousness).