On the matter of the many-worlds interpretation of quantum mechanics, I came across this fascinating article; below is an abstract:

“Or at least one of your future world-paths will… In the many-worlds interpretation of quantum mechanics, all outcomes of any experiment are realised. Rather than the wave function, a superposition of all possible outcomes, “collapsing” to a single outcome, in the many-worlds interpretation the universe itself branches into all the possible outcomes. … The physics world thought this interpretation came along with a bit too much metaphysical baggage to be taken completely seriously. Nevertheless the mathematics are certainly self-consistent, I think.” Source: Play the Quantum Lottery!

Personally I find the idea of the Many Worlds interpretation of Quantum Mechanics unpleasant for this reason: A logical conclusion which one can draw from every outcome occurring in the many-worlds interpretation, it that all possible outcomes have been determined or played out.

Whether you do or do not subscribe to theological or secular systems, the many-worlds interpretation leads to a logical conclusion in that there is no free-will. Under this interpretation, you have no choice, as the outcome of what you do has been pre-determined and will be accounted for in every possibility (or universe). So if you decide to turn right one day, instead of left, the world you then ‘exist’ within may be less favourable than you might expect. It could be argued that free will has not been removed, as any choice you make, will make, or had made, will all be played out and without an (external) observer to keep everything ticking over.

So you do have free will within a multiverse? Well I suppose it all depends upon what your definition of free will is. To me a multiverse does not allow free will. An example of free will, excluding acts that create closed loop paradoxical (grandfather) systems, would be when you turned left instead of right. The scenario that played out is then not repeated within another universe, but exists solely in one universe only – assuming that other universes exist.

What about if I am not looking or there is no external observer and I don’t know about other choices being played out, surely then I am still choosing? Well not really, by lacking the knowledge of a system does not mean that it does not still exist. So if no one was looking at the stars at night, would they still be there the following night? It all comes down to what the ‘truth’ about the wave function collapsing is. And having an external observer within a multiverse framework, can point to a conclusion that all paths are predetermined. But an external observer is still outside of the multiverse, so how would you know? It just comes back to Bishop Berkeley’s philosophical argument on the existence of an external observer.

Under the Copenhagen interpretation of quantum mechanics, the wave function contains all information one can know of a quantum object, both its position and speed. However the wave function resolves with its own deterministic resolution, in that only a quantum object’s speed or position can be accurately measured at once; as one cannot measure both the quantum object’s speed and position accurately simultaneously (the uncertainty principle), all that can be predicted is the wave function (Schrödinger equation) and our knowledge of any quantum object from a classic perspective is halved.

However even with our knowledge being limited, it is not so limited under the Copenhagen interpretation of quantum mechanics that predictions cannot be made. Even within this acquired knowledge there are limitations, such as where space-time becomes so severely warped by strong gravitational fields, our knowledge can become opaque and or obscured by such regions of space-time.

Key to any system’s knowledge is the observer; the observer them-self becomes entangled with an experiment to measure a quantum object’s position or speed accurately, or to even obtain both with a certainty degree of predictable accuracy. The observer becomes an extension of the quantum complexity, however as the observer exists within a classical framework within space-time, the quantum object becomes juxtaposed and closed off from an entire view to the classical world, but information will leak into the classical world from the quantum world due to entanglement. The observer does not only interfere with an observation, they also become part of that system and the knowledge contained within it. However as quantum objects exist or are perceived within the geometry of space-time, knowledge of a system is also restricted as to how fast that information can be transmitted beyond the local region in which the observation took place; in classical observable terms, this is determined by the speed of light.

Light coming from the Sun takes approximately 8 minutes to reach the Earth; from distant galaxies, light can take thousands (or greater) years to reach the Earth in which an observer can see, for example, a quasar galaxy. The information accumulated from observations of a quasar galaxy, then becomes part of a knowledge state to those who have that information. What I am trying to reach at in this thread is that, space-time itself has a direct effect on quantum observations. Just as Einstein pointed out that space can be experienced different for different observers, the quantum information within a system in which an observer inhabits, also becomes tied into those same classical observational limitations.

Further more, as any system is within the Universe, there is a further limitation placed on the observer. As the observer is part of the system itself (and therefore part of the Universe), not only is the observer entangled within any observation, the knowledge of the system is restricted to limitations of space-time localisation. As the observer cannot step out-side of the Universe to observe it as a whole, they cannot know all the information at once; they them-self are trapped within and become part of the wave function itself.

By observing an object’s quantum state, classical information can be obtained which will lead to information of a system; as the psi wave collapses the information becomes ‘fixed’ and systems knowledge can be known with certainty (quantum decoherence results); the quantum object’s information becomes ‘revealed’. However this information still does not always lead to a full understanding of the system itself – for example, the two slit experiment – as you will only ever obtain partial results if you view the information from a classical perspective.

Where as With the Copenhagen interpretation of quantum mechanics, choice is allowed, spatial-temporal events are not ’set-in-stone’ until observed and that information becomes knowledge of the (local) system. But as mentioned before, this knowledge is still limited, in the quantum world it is the wave function which is revealed; in the classical world, our interpretation of events are understood by accurately knowing either a quantum object’s position or speed.

To complicate matters, experiments have been carried out which demonstrate that larger objects may also exhibit quantum properties. So not only photons, electrons and other small objects, but also larger discrete objects within space-time events, such as Buckminsterfullerene and bacteria.

Einstein once said, ‘God does not play dice’; personally I don’t like the many-worlds interpretation. Although I favour the Copenhagen interpretation, I would say that I agree with it about 75%; there is still something missing, and maybe the search for a unified theory will answer the missing questions, but I have my doubts. I like the idea of having choice and not being a marionette existing within the many-worlds interpretation.

However, the whole point is to keep on debating, as there are many chasms in knowledge. Science is the search for truth and understanding and interpreting information. There are lots of theories, and all too often, theories can become ’set-in-stone’ and new ideas discarded. You only have to look at examples in ‘history’ for this, such as Faraday, Tesla, el. al.