The Holographic Universe
As explained in Quantum Theory the world is only determinate where you have observed it. So your observations define this world, and all else is unreal. In order to fully understand how this works, we need to fully understand the nature of the reality one actually experiences directly, the ‘perceptual reality’. This also leads to the irrefutable evidence for the relative state world as described by Everett.
The perceptual reality is your perception of the world, meaning the representation of reality that is generated by the brain, using all the information from the senses of the body. We now know exactly what the perceptual reality is, though this may be unfamiliar. The brain produces a representation of the three-dimensional real world, in the form of a three-dimensional virtual reality. You are experiencing the look of this reality at this moment. This is the observation you are making at this moment. This is recorded in memory along with all your other memories. The integrated synthesis is your known world. The brain takes all this information and produces a virtual reality that represents the known world. This is what you are interacting with whenever you think about any aspect of the world not in your immediate perception, where you went yesterday, or what might be happening now far away. And as Deutsch states, this virtual reality is mentally projected onto the real space-time world. I call it the world hologram. This is all described in detail in The World Hologram.
So this is how the perceptual reality of the human organism works. The world hologram is just the display of the human navigation system at work, the ‘sensorium’. Remarkably, however, this is also a structure of information of extraordinary significance in the field of physics. As QBism describes, only the observations made define the determinacy of the real world of this individual. Thus it is determinate only where defined by the world hologram. And this resolves one of the most peculiar and challenging paradoxes of the quantum theory.
The Holographic Universe
Despite a century of concerted effort, neither physicists or philosophers of physics have found a compelling explanation of of what quantum theory is telling us about the physical world, as Wayne Myrvold states quoted in Quantum Theory. In fact, however, the physicists have not only discovered the nature of the reality defined by the new physics but described it in detail, but there has been no framework in which to understand what it really means. This is the ‘holographic universe’. As Kostas Skenderis explains:
The idea is similar to that of ordinary holograms where a 3D image is encoded in a 2D surface, such as in the hologram on a credit card. However, this time, the entire Universe is encoded. (2017)
This is the holographic principle of Gerard t’Hooft, discovered in 1993. The problem is it makes no sense. The entire three-dimensional universe is actually a two-dimensional surface that somehow gives the illusion of a real three-dimensional space. This would mean we are actually all like cardboard cutouts! As Jacob Bekenstein describes:
The holographic principle states … that volume itself is illusory and the universe is really a hologram which is isomorphic to the information “inscribed” on the surface of its boundary. (2003, 59)
As Robbert Dijkgraaf describes:
What’s happening in space is, in some sense, all described in terms of a screen outside here. The ultimate description of reality resides on this screen. Think of it as, kind of, quantum bits living on that screen. And this, like a movie projector, creates an illusion of the three-dimensional reality that I’m now experiencing. (2019)
It sounds so surreal that it has received very little attention, but as Lee Smolin writes, this is for sure:
… an idea which at first seems too crazy to be true, but which survives all our attempts to disprove it. (2000, 178)
The resolution is simple. This is the correct description, but this, of course, is not a fiendishly counter-intuitive redefinition of the ordinary world, the objective physical reality of the quasi-classical world. This is the precise and correct description of the superworld.
The superworld is determinate only where observed by this individual. So it is the observed surface that is determinate, and all else is unreal. And the world hologram is the definition of the observed surface. So the holographic principle is precisely correct, but the ‘screen’ is not at the outer limits of the physical cosmos, but just the outer limits of the perception of the individual. Which makes rather more sense.
There is solid proof. As Leonard Susskind discovered in 1995, the ‘entropy’ of ordinary mass is proportional to surface area and not volume. The entropy is a measurable physical property that essentially defines the possible energy of a system. This leads directly to the holographic universe as Bekenstein describes because it means that:
… volume itself is illusory and the universe is really a hologram which is isomorphic to the information “inscribed” on the surface of its boundary. (2003, p. 59)
This is the superworld, the type of world on which we actually do our physics experiments. And in a superworld there is no mystery about why the entropy is defined by the observed surface. Everything not observed is the superposition of all possible states, so the only definition of the entropy is given by the observed surface because all else is indeterminate.
But volume is not in fact illusory. The superworld is a superposition of quasi-classical worlds, each one a three-dimensional volume of the arrangement of matter and energy. It is all of these worlds all at once. The holographic universe describes the net effect with precision but this is nonetheless a real physical world. Volume is not illusory. The paradoxical nature of the holographic universe lies in conceiving of the quantum cosmology as a surreal description of the quasi-classical world. The holographic universe is not a surreal spherical causal shell at the outer limit of the cosmos but just the observed surface of the physical environment.