Tuesday, 28 August 2012

Splitting Reality – The Many-Worlds Theory

Let your soul stand cool and composed before a million universes. 
– Walt Whitman 
Through books, TV and film, the idea of parallel worlds is a widely recognised phenomena in our culture today. From a quantum physics perspective, it’s instructive to understand the origin of this idea.

As explained in a previous article, Schrodinger came up with his famous cat in a box experiment to illustrate what he believed was the absurdity of the Copenhagen interpretation. The Copenhagen interpretation is the theory of physicist Niels Bohr, that states a quantum matter exists in all states at once (a wave) until forced to chose one state when observed (a particle). Ironically it’s Schrodinger’s cat thought experiment, intended by him to deride Bohr’s theory, which has become the preferred way to explain the Copenhagen interpretation.

An alternative idea that grew from this was Hugh Everett’s 'Many-Worlds' theory. He agreed with the wave ideas of Bohr, however he argued that rather than an object being forced to become a particle when it was observed, it actually created a split in the universe to allow for each possible outcome. A disturbing example that illustrates how this could work, is when someone is nearly killed crossing a road. In the Many-Worlds theory the universe splits at that moment – in one reality the person dies and in the other reality the person lives. Using this model in any given moment, the universe is constantly splitting like the branches of a tree for each new potential outcome and creates an infinite number of parallel realities.  

Whilst the Many-Worlds theory isn’t the only one to promote the idea of parallel worlds to explain the behaviour of objects at the quantum level, it has attracted serious interest and research in recent years. Keep this in mind when you next cross that road – you could be about to split the universe in two.

The below video is a useful visual explanation of the Many-Worlds theory.


  1. Fascinating stuff, if a little devoid of practical usefulness (parallel world theories, not your post). :)

  2. Oh I don't know... I find it quite useful to draw upon these theories when writing! ;o)

    1. In another universe I didn't make the above comment and showered you with effusive praise.

    2. What comment? I'm already in the other universe! ;o)

  3. Hi Nick, whilst being aware of the many worlds theory, I've never heard of the term 'Decoherence' before - really good vid' that - top post, sir.

  4. Hi Nick can you contact me on skype pharaohmoan would like to discuss something urgent I have stumbled across!

  5. Hi Nick,

    Interesting post. The multiverse theory is also an attempt to explain the very unlikely situation of our actually being here. The explanation being that every scenario of the universe's development is played out.
    But, I think the believe in this theory has ran recklessly ahead of any evidence. Apart from the string theory - which is also still just a theory - there doesn't seem to be anything concrete to back it up. Please correct me if I'm wrong. But, not only do people believe in it, there are theories about multiple self's interacting. I believe 2 science students in recent years committed suicide, carrying out a multiverse experiment - though I can't find an article on this... So, is it just a new religion?

    Thanks for the post. It was interesting.

  6. Hi Fiona,

    That's the thing about theories like this... they are just that. Of course throughout history our species have had a human-centric view of the world around us. First of all the Earth was flat... then we thought our planet was the centre of the cosmos... then we thought the sun was the centre... and then we discovered just how vast the universe really is. In this context, as our knowledge has expanded about the universe around us, our small human-centric model is challenged. Why just one big bang? In fact I'd go further and say isn't it more likely there have been multiple ones? One of my personal favourite multiverse theories is that our universe is like one soap bubble... just one of many that sometimes overlap. One thing's for sure, this is all a deeply fascinating area of physics and will cause lively debates forever!

    Best wishes,


  7. Great post dude!
    I just finished a book on how we can make use of the Many-Worlds Theory to achieve life goals.
    It's called: "Moving Through Parallel Worlds To Achieve Your Dreams." Available in print @ Amazon.com If you enjoy the theory, you'd love the book. I appreciate your support!