You are an officer aboard the starship Enterprise and it's time to beam down to the planet. You step onto the transporter pad and O'Brien jiggles his levers, and the transporter beam surrounds you . . . but there is a malfunction. Although it does transport you to the planet, as planned -- it also leaves "you" still standing on the transporter pad. For some reason it copied rather than transported you.
Since you're still on the ship, you consider the "you" on the planet to be a "copy". Although it's you in every way, you believe you reign supreme because you were there first. If it comes down to who owns that iPad-49, it's yours, baby. No doubt about this -- at least, as far as you're concerned. The guy on the planet may feel differently.
So although there are two of you, identical in every way, you are convinced that you're the "real" one. But really, what has happened here? If the machine had worked properly, it would have put you on the planet without leaving you behind. It did put you on the planet. The problem seems to lie in the continued existence of the "original" you. Unless that original is destroyed, you can't believe that the transported being is really you. I call this the "destruction principle".
Let's consider this question with a different example. We're told that we will be able to "download our minds into computers" within a few decades. The way it's spoken about, the downloaded being will be you in every way, except it won't have a body. But here's the thing -- after you've "downloaded your mind", your old self will still exist. And you know that will make you consider the "original you" to be the "real you".
But let's apply the destruction principle here and see what happens. If the process of downloading your mind killed you, it would indeed seem like you traveled into the computer. It's the destruction that accomplishes the trick. As long as the original you disappears, the new you will seem to be you.
So the rule seems to be -- Kill the original if you want to perceive the new being as having the identity of the original "self". That's the winning formula. But what does this say about the reality of our "selves"?
It's weird, isn't it? This is fodder for hundreds of stories and I plan to write a few of them. I want to blast this concept into people's brains. The lesson here is that our "selves" are malleable. Identity is a matter of perception, or it soon will be. The truth is that we are infinitely adaptable; we can change and become all sorts of things, and in the future this is exactly what we will do.
Our flesh bodies are merely our current "ride". And I don't know about you, but I'm ready to move on up.