Quantum immortality is one of those ideas that’s managed to burrow its way into my thoughts and has remained there stubbornly every since. I’ll sometimes pick at it in my mind much like you might worry a loose tooth with your tongue. It’s an idea that balances just enough logic and insanity that I doubt I’ll ever come to a personal resolution.
I don’t have a science background myself, so I only really understand the basics of everything I’m talking about. To actually articulate what’s going on, you’d need somebody who can first explain quantum physics in a meaningful way; I chose to use a silly video, so there you go.
Here’s the short version, which is still several paragraphs long. We’re going to assume that quantum physics mean we don’t live in a universe but rather an infinite multiverse. In the multiverse, there are an infinite number of different versions of reality. There’s a reality where I ate breakfast this morning and one where I didn’t. There’s a reality where I’m actually named Zaphod Beeblebrox. There’s a reality where I’m a Republican. There are an infinite number of different versions of myself just as there are an infinite number of different versions of yourself. And those are just the small differences. There are versions where humanity didn’t exist, where Hitler won the war, where Coke comes in blue cans, and so on.
So, in this multiverse, there’s the current thread of experience that believes itself to be me. As far as I’m aware, I’m the only version of me that exists; I’m closed off from all the other infinite mes. The reason for this has to do with probability and the states of electrons, but I don’t have enough authority to articulate the specifics. Let’s just assume this is the way it is.
Each time a choice occurs, my personal thread of existence chooses one option and follows it. I am now living in the reality where I ate breakfast this morning. This means, however, that my action also spawned a new reality where I didn’t take that action. Thus, my thread of experience has fragmented and spawned new threads, one for each choice and each variable of my life. The number of variables is incomprehensibly large, but we’re talking about the infinite.
Quantum immortality is the idea that my thread of experience will shift accordingly to continue itself. Basically, whenever a variable occurs where one choice will lead to the termination of my experience thread, I will shift to the version of reality where that didn’t happen. In theory, I could test this very easily by putting a gun to my head and pulling the trigger. If quantum immortality is correct, I should experience a misfire every single time, no matter how statistically improbable. I should note, however, that the idea only guarantees that I’ll survive; I could very easily survive the gunshot itself and be crippled without violating the principle idea. You can understand why I’m not eager to test it out.
There’s another reason why testing it out is unfeasible. Even if I do perform the experiment, I’ll now exist in a version of reality where I pulled the trigger fourteen times and survived unharmed. But each of those attempts will spawn more and more versions of reality where I pulled the trigger and died. You, the observer, with your own thread of experience, will almost certainly not progress to the same version of reality I do. You will almost certainly be in a reality where I died, if not the first time then the second, third, or fourth time, and so on. It’s virtually impossible that you’ll end up in the same version of reality that I do, where I make it out alive.
Of course, there would be a version of you in the reality where I do live, and you’d be correspondingly impressed (and probably pissed about such a rash action). But that version of you wouldn’t be the you that is reading this article now, because each you has its own thread of experience that doesn’t overlap. You are thus almost certainly not the you in this hypothetical miraculous survival scenario. This explains why we don’t currently live in a universe where someone else has performed this experiment successfully. Anybody who does will almost certainly die from our perspective, because the experience of immortality is only true for the person pulling the trigger.
Since the idea is based on probability and your consciousness shifting to the variable that ensures its own continuation no matter how unlikely, I imagine you would still die of old age due to the fact that eventually, the probably of your survival becomes zero and there is no further version of reality for you to shift into.
Or maybe not; maybe you just shift into the version of reality where you miraculously discover the fountain of youth and keep on living. Who knows?