Authors, philosophers, and scientists have explored these concepts in detail, and it’s my hope to introduce them to you, not to claim them as my own.
There is a recent notion that some people alive today may achieve biological or technological immortality. Biological immortality focuses on things like prevention and repair of cellular damage, immortality of cell lines, replacing aged organs with newly-grown ones, and removal of what I can best call “crud” that accumulates in your body as you age. Technological immortality involves replacing failing biological components with artificial ones, replication of your personality, in essence porting it from wetware to hardware or software. We do much of this now under the umbrella of general medicine, achieving longer and healthier lives.
What I want to explore is the philosophical question of whether or not immortality can be conferred on an individual, or if the conversion to immortality conceptually kills the original and produces an immortal copy.
While our structure remains relatively constant over time, the atoms that comprise us change regularly as cells replace themselves. On average, you are made from completely different atoms every seven years. If you define yourself based on the atoms that are in your body, or specifically your brain, then you’ve already been replaced Y/7 times if you’re Y years old. Any memory you have from eight years ago was stored in cells that have died and left copies. You can still access those old memories because cell replacement doesn’t change structure, assuming everything goes well.
If medicine did allow us to extend our cell lines indefinitely, avoid replication errors, fix or prevent inherited genetic diseases, and remove accumulated “crud,” we could live forever if we avoid the same things that can kill us prematurely now. We’d still be ourselves – at least as much as we are ourselves now, with our atoms changing every seven years.
An immortality solution that emphasizes technology could eventually replace each part of your biological body with a piece of technology. To jump ahead slightly, let’s assume every organ, including the brain, can be replaced with a modular piece of technology that performs like the original.
What if your biological brain were put in a technological body? Simply doing this would significantly extend life, since a lot of things that damage the brain are caused by the rest of the body. In conjunction with biological brain immortality, it could confer full immortality.
Would your real brain in a technological body still be you? If you think of our brains as piloting our bodies anyway, then you’d probably say yes. To me, this seems reasonable.
What if, instead of using your biological brain, some process scans your biological brain and produces an exact copy of it in hardware and/or software? Does that confer immortality to you, or does it merely copy you? What if the scanning process is destructive, resulting in some time when the pattern in your brain that is you isn’t complete? Would that murder you and create a copy? To me, I’d consider it murder for a scanner to tear my brain to bits as it studied the structure.
Those are the edge cases. It gets trickier when you think of the middle ground.
What if there were a way to slowly replace the biological structures in your brain with technological ones? Your brain already replaces cells on its own, and we don’t generally think of this as killing us, so how is it different for a technological process to take over? One by one, neurons, axons, dendrites, would be replaced by functionally-equivalent nanotechnological components. If we set the timescale for the conversion to be seven years, then we ensure that it happens no faster than nature. Are you still you when one of your neurons is technological? What about 100? What about 10 billion (roughly 10%)? One thing is assured: by the end of the seven-year process, your biological brain will be gone.
Wait, it gets creepier.
Let’s say you’ve made the switch to a nanotech brain, as above. Assuming you still think you’re you, and not the murderer of your identical twin, what would happen if you converted your nanotech hardware brain into a software brain? Is there a difference between two things if they behave the same? As before, the conversion could be done gradually, over a seven-year period, slowly deactivating pieces of the hardware brain and activating equivalent software representations in a computer brain. Would you still be you? If the answer is yes, then what exactly are you now? Are you the structure that the software represents?
It gets stranger, too.
One of the authors I’ve read suggests that if you’re ok with neurons being replaced by functional equivalents, then the physical geometry of these neurons in relation to the others doesn’t matter much. Instead of direct physical connections, why not go wireless? You could store parts of your brain in your house and keep just a small portion of it in your body for tasks like reflexes where latency is an issue.
To me, the edge cases seem clear: I’ve had biological immortality conferred upon me if my brain is able to maintain its normal biological process indefinitely; I’ve had an immortal copy made if someone reads and copies my brain in a single step, and I’m murdered if the read was destructive. What bothers me is that I don’t know how I feel about something that slowly destructively copies my brain in place. The continuity seems to be what throws me, because it would offer the same continuity as biological brain immortality, but the end result is that my biological brain will have slowly been destroyed. Of course, if continuity problems bother me, I should stop sleeping.