This is inspired by Max Tegmark‘s Our Mathematical Universe: My Quest for the Ultimate Nature of Reality: I have been thinking about this since I finished the book and I cannot find a convincing argument against the thesis (certainly the ones Tegmark uses in the book didn’t impress me – but perhaps I misunderstood them.)
So, let us conduct a thought experiment that might suggest “you” can live forever.
In this world we assume that you don’t do anything dangerous – such as commute to work. The only factors that could kill you are the normal processes of human ageing (and related factors such as cancer): your fate is completely determined by chemical processes in your body.
And we accept the “many worlds” view of quantum mechanics – in other words all the possible quantum states exist and so “the universe” is constantly multiplying as more and more of these worlds are created.
Now, if we accept that the chemical processes are, in the end, driven by what appears to us as stochastic (random) quantum effects – in other words chemicals react because atoms/electrons/molecules are in a particular range of energies governed by the quantum wave equation – then it must surely be the case that in one of the many worlds the nasty (to our health) reactions never happen because “randomly” it transpires that the would-be reactants are never in the right energy state at the right time.
To us in the everyday world our experience is that chemical reactions “just happen”, but in the end that is a statistically driven thing: there are billions of carbon atoms in the piece of wood we set fire to and their state is changing all the time so eventually they have the energy needed to “catch fire”. But what if, in just one quantum world of many trillions, the wood refuses to light?
So, too for us humans: in one world, the bad genetic mutations that cause ageing or cancer just don’t happen and so “you” (one of many trillions of “you”s) stays young for ever.
The obvious counter argument is: where are these forever-young people? The 300 year olds, the 3000 year olds? Leaving aside Biblical literalism, there is no evidence that such people have ever lived.
But that is surely just because this is so very, very rare that you could not possible expect to meet such a person. After all, around 70 – 100 billion humans have ever been born and each of them has around 37 trillion cells, which live for an average of a few days (probably) – so in a year perhaps 37 billion trillion cell division events – each of which could spawn a new quantum universe – take place. That means the chances of you being in the same universe as one of the immortals is pretty slim.
Yet, on the other hand, we all know someone who seems to never age as quickly as we do…
…I’d be really interested in hearing arguments against the hypothesis from within the many worlds view of quantum physics.