Quantum Immortality (or how to be the luckiest person alive)

Firstly, I'd like to thank you all for visiting my blog, and I'm delighted with the positive reception there's been to my first few posts. Hopefully there'll be many more to come.

Today I thought I'd talk about quantum immortality, as it's quite an intriguing theory that can drive you mad thinking about it.

It's quite important that I first explain a little about quantum mechanics (don't worry, there won't be a test). In quantum mechanics, particles are described as wave functions. I don't want to go too in depth, so let's just say a wave function is 'a bit of maths' that describes how the particle behaves. The thing about wave functions is this - they describe the different possibilities of what the particle could be doing, and the probability of each possibility being observed. Confused yet?

The Everett many-worlds interpretation of quantum mechanics states that for each possible outcome of an observation of the wave function there is a universe in which that outcome is observed.

A way of looking at this is a coin toss. Before the coin is tossed, the outcome could be heads, or it could be tails. In the Everett many-worlds view, there is a different universe for every possible outcome of the coin toss - one in which it is heads, one in which it is tails, one in which the coin is dropped, one in which it spins five times before landing, one in which it spins six times, etc.

Now we get on to quantum immortality. Suppose I take a pistol, and point it at my head. Then I pull the trigger. Despite the overwhelming number of outcomes that involve me laying on the floor with a rapidly expanding pool of blood forming underneath my head, there will be a few universes in which I miraculously survive - the gun has jammed.

Now, let's say I'm in one of these universes in which I survived. I then take another pistol, and repeat the experiment. Again, there are a few universes where I remain unscathed.

This process continues ad infinitum - no matter how many times I repeat the process, a universe exists in which I survive.

From our perspective, this is merely a statistical inevitability. From the perspective of myself inside that universe, I have attempted to shoot myself in the head a hundred times, and not been successful once.

Wrap your brain around that one.