I've been pondering consciousness again. So, consider this: One of the most intriguing sci-fi tools used on Star Trek is the transporter. It uses the equivalence of matter and energy to send people and objects between the ship and the planet below. It converts the matter of a person's body into pure energy and then beams that energy to the the planet. It then reconstitutes the matter from the energy stream using the information contained in the signal.
But on one episode of Star Trek: The Next Generation, a transporter malfunction produces two Commander Rikers because an energy surge in the unit on the planet caused the energy stream to produce a Riker on the ship, where he was actually going, and a copy on the planet. But neither Riker knew about the other until years later when they encountered each other on the same planet, where the duplicate Riker had been stranded.
But here's my question: Which one was the "real" Riker? If both Rikers were created from the same signal, that means they were not only identical genetically and physically, but also with regards to brain chemistry. Every neuron was equivalent in every way. They had the same thoughts and the same memories. Yet, when they met each other, they just treated each other as though they were twins. They had separate personalities, owing mainly to the fact they they had lived in separate environments for a few years.
So let's suppose a normal transport. Is the reconstituted person on the planet really the same person as the one climbing aboard the transporter pad on the ship, or is he an identical twin, like Riker? And if he's not really the same person, which of course he wouldn't be because matter is not being transported, only the energy that the matter produces, then does that mean every single transport destroys one human and produces another identical one? Isn't the destroyed one now actually dead?
Of course in practical terms, it makes no difference to the people who are not being transported. They just see what looks and acts like the same guy. He has the same memories and is on the same mission. But, in reality, the pre-transport human being is no longer around.
I'm using the Star Trek transporter as an analogy to what may eventually be likely to take place. In the future (and maybe the not-so-distant one) there will be a means of transferring the mind of any human into an android or a computer brain. The transferred mind will have the same sense of humor, the same personality, and all the recollections of the original human. It will be conscious. But will it possess the SAME consciousness as the human donor? Just because it might become possible to transfer a mind into an android or even an artificial organic brain doesn't mean it was actually a transfer. It might be just a copy. If so, the original mind is still going to be gone. It won't matter so much to the loved ones because for all practical purposes, the donor's mind is still intact. It also won't matter to the deceased mind because, well, he will be dead. But you can't really call it immortality because the original mind has been lost. If I were an identical twin at death's door, it wouldn't bring me any peace knowing that my twin could carry on in my place, even if he had had all the same experiences and memories as me. It still wouldn't BE me.
This leads to much deeper questions about what it is that actually makes up the "I" in me. What is my consciousness anyway? Is it a soul that is somehow cosmically connected to the universe? Or is it just organic neurons in my brain arranged in a manner that is unique to me? It's a question that has puzzled scientists, philosophers, and theologians for centuries.