The Indeterminate World
This page explains the physics underlying the concept of world superposition.
Taking the basic physics at face value, all possible worlds exist. This is the basis of Hugh Everett’s many worlds theory, as explained in the Many Worlds page. And this aspect of the theory is now generally accepted in one form or another.
As cosmologist Max Tegmark (2003) explains in Parallel Universes, all possible worlds exist in the universe. And this means there is a vast number of identical copies of each individual in the universe of all possible worlds. In other words, every possible variation of a world that contains you, exactly as you are here and now, must actually exist. Therefore, as he explains, there is a huge number of identical copies of you. There is no question all these copies are the same person. As Deutsch reflects, given that there all these identical copies of oneself:
… which one am I? I am, of course, all of them. Each of them has just asked that question, ‘which one am I?’, and any true way of answering that question must give each one of them the same answer. (1997, 279)
The Indeterminate World
When it comes to quantum theory, there is a further startling fact to take into account. All the many worlds are here and now. This is the nature of a Level III multiverse in Tegmark’s explanation. As stated by Lev Vaidman:
… in addition to the world we are aware of directly, there are many other similar worlds which exist in parallel at the same space and time. (2008)
They all exist in exist in superposition. This follows automatically in the many worlds theory, as explained on the Many Worlds page. The implication for the reality of the individual person is crucial.
The reality one experiences directly is the perceptual reality that the brain produces. This is described in detail in The World Hologram. As explained there, the perceptual reality is a holographic field of information, the ‘world hologram’. This is how the brain represents the world known from all the observations made over a lifetime. The key point here is that all the identical copies of you must have identically the same world hologram, otherwise they would not be identically the same person. But when all these identical copies are superimposed we get a remarkable result.
If you superimpose identical copies of information, you get just that information. If you superimposed two identical copies of this page, you would get just this page. Therefore, when all the identical copies of the world hologram superimposed, there is just one world hologram. Therefore, in the many worlds of quantum theory, there is just one world hologram, one perceptual reality, for all these identical copies of the person.
Now for the next strange implication. Naturally, by definition, this world hologram is present in all the worlds in which an identical copy of you exists. This would seem to mean that to experience this world hologram, in other words to experience the perceptual reality defined by this world hologram, is to experience the reality of all the worlds in which it is instantiated, all at once, superimposed. This is here called the world superposition.
Shortly we will look at why this could be what one experiences, but first we will look at the implications if this is the case. In the universe of all possible worlds, many of the worlds in which an identical copy of you exists will be very similar. Certainly all the things you have observed are identically the same in all of them. Therefore, with respect to the aspects of the world that have been observed, all these worlds are identically the same. However, with respect to the rest of the world the opposite must be true. This is the set, or class, of every possible world that contains a copy of you. And this means that every possible variation of a world that contains you is included. Therefore, in the superimposed sum of all of them, every possible variation of how the world could be, elsewhere, where you have not observed it, is included. And this means that in the world superposition, everything that you have not observed is indeterminate. In other words, this is exactly the reality of the QBism world.
A superposition of physical worlds may sound nuts, but this is simply how quantum mechanics works. Everything physical, including whole worlds, is defined by the wave function. This is the basis of quantum theory, the most successful theory humankind has ever produced. Therefore, technically, a superposition of worlds is an entirely feasible and applicable principle. Theoretically, therefore, this is all standard physics so far. Two things are required for the world superposition to be the world you are actually experiencing, as QBism would seem to suggest. Firstly, you have to be the one in this position. How this can be considered to be the case is explained in Identity, following on from the logic presented in The World Hologram. In essence, the real you, the you ‘in here’, is the world hologram. You are the holographic field of information inhabiting the body from moment to moment. Secondly, the nature of consciousness powerfully suggests that this is all the case. This is explained in detail in Universe Consciousness, and the evidence is presented. The experiencing consciousness, that which experiences the perceptual reality, is not, cannot be, a property of the human brain. It is a property of the universe itself, as held by a number of great physicists and philosophers. This means it is a non-local phenomenon, or if you prefer, ubiquitous. And to this consciousness, there can be no such thing as identical copies of a structure of information. All copies are simply the same thing because all are experienced simultaneously. And this means that in experience your physical world is the superposed sum of all those versions of the world.
It is this that gives rise to all the strange properties of the QBism world. In the superposition of worlds, everything you have experienced and observed is identically the same in all these worlds. So that is just how things are. All those things are determinate. But exactly the opposite is the case with respect to the things you have not observed. Every possible variation of those things, elsewhere in the world, is included in the superimposed sum. This means that all those things are indeterminate in this world. That is how quantum mechanics works.
This logic does not apply to the body of the observer, the physical entity. Each observer is a physical part of a specific physical world due to decoherence. However, the individual here is the entity on the inside view, the world hologram. And with respect to this individual, this logic applies absolutely.
So in the physical reality of the individual, only the things which have been observed are determinate. And, the record of observations is therefore the record of everything that is determinate. And everything else is indeterminate. That is exactly the reality of the QBism world. Once again, this is not a new idea. This is a ‘centred world’ as defined by Vaidman, one:
… centered on a perceptual state of a sentient being … In this world, all objects which the sentient being perceives have definite states, but objects that are not under her observation might be in a superposition of different (classical) states. (2008)
QBism solves all the problems with quantum theory. Now it also has an ontology in the well-established physics of Everett’s many worlds theory. The key point is that with this understanding, both the severely different views of physical reality are correct. On the inside view, as described by QBism, the world is indeterminate except where you have observed it. But the ordinary worldview is correct as well. In the ordinary world of objective physical reality, the world is a single, determinate physical domain. Both are correct; they are simply different views of the same universal system.
The missing piece of the puzzle is that quantum theory defines two different types of frame of reference. The difference is further explained and illustrated in the page on Schrödinger’s Cat. The objective-view ordinary world is real and valid, but this per se is not what we encounter. One encounters the world superposition, the simultaneous existence of a whole class of ordinary worlds, and this is determinate only where observed. And of course, when we go to do experiments on reality, this is what is revealed. This is what has given rise to all the confusion about quantum theory. The equations tell us of a real objective physical universe, and the phenomenon of decoherence means this is laid out as the many worlds of Everett’s theory. But the experiments tell us that it is indeterminate except where observed. The new worldview dissolves this paradox. Both are completely correct in their own way. And both are wrong in the frame of reference of the other.
What has been missing is the fundamental nature of the superposition world. It is a different kind of frame of reference to an ordinary world. It is of different ‘logical type’. Logical type, discovered by Bertrand Russell, addresses the difference between a set and the members or elements of that set. They are utterly different kinds of things, and thus their properties may be utterly different. The physical world of the inside view is the superposition of a set of physical worlds of the outside view, which is why it has the extraordinary properties described in QBism. So the conventional idea of the objective reality of an ordinary world is right, but it is only one half of the story. In other words, it is one of two different, fundamental frames of reference. Both are equally real, valid and ‘ontological’, definitions of what actually exists. The truly major upheaval in physics is that objective physical reality is only one of three levels of logical type, all three of which have to be addressed in order to make sense of the new physics.