Sometimes in mainstream physics, our perception of the world is considered intact and accurate. The classical / quantum perception paradox may have originated from this kind of assumption. Reality at the classical level is definite, concrete, and logical. Quantum physics, however, pictures a quite different reality, a multi-factual reality full of uncertainties and classically illogical and unacceptable features. Cause and effect is a feature of classical perception of reality. Werner Heisenberg once claimed:
"In as much as all experiments are subject to the laws of quantum mechanics, through the quantum mechanics the invalidity of the law of causation is definitely established"(Greenstein & Zajong. 1997).
The measurement/observer problem (collapse of superposition of states to one classical state because of measurement by an observer) remains the single most important gap in quantum formalism. The founder of quantum mechanics, Neils Bohr, believed that somewhere between the subatomic world and the world of big objects, the rules change. Yet the recent quantum mechanical experiment with large molecule such as C60F48 cited above pales the belief of a cutoff point for quantum effect (Nairz et al. 2003).
Werner Heisenberg believed that wave function is not part of objective reality; instead, it is the embodiment of what we know about reality. Our ignorance about the exact location of electron is reflected in the wave-function postulate. When we measure its location, our knowledge is definite; therefore, our uncertainty collapses and we gain a classical understanding of the object. However, Tonomura’s double-slit experiment clearly demonstrates the actuality of waves. David Bohm, on the other hand, argued against superposition. He believed that particles do possess definite position and other properties, but uncertainty principle introduces a limit to what we can know about these properties. However, the interference observed in double-slit experiment supports the idea that a single incoming wave-particle is in a state of superposition.
How we reach to a classical reality out of quantum mechanical universe is the major puzzle. Hugh Everett postulated that wave function is present and never collapses. He believed that every estate of the wave branches out and spawns a new universe (Greene 2005) Therefore, any prediction made by quantum mechanics actually happens in innumerable parallel universes. This “many worlds” interpretation of Everett surpasses one’s wildest imagination. For one, it advocates that there are 10100 copies of me and you. Even worse, the number is ever growing.
Giancarlo Chirardi, Alberto Rimini, and Tullio Weber proposed that superposition is inherently unstable and it must collapse to a definite state. According to them, although it rarely happens, the collapse of just one particle in a large object (containing innumerable particle) is enough to initiate the collapse of the other constituent particles and bring the whole object to a definite state. Opponents of this idea argue that there is not a shred of evidence to support it (Greene 2005, 206).
Perhaps the most popular solution for wave collapse is de-coherence, suggested by Dieter Zeh in 1970. It argues the unlike insulated laboratory experiments, real-life objects are constantly interacting with other particles and cosmic rays. The wave function of the real-life objects through constant bombardment by other particles somehow reduces the wave to a definite particle with definite properties (Greene 2005, 210). Opponents of this theory argue that the particles from the environment are themselves in a superposition of states. Their interaction with the object only complicates the superposition further (infinite regress) (Greenstein and Zajong 1997). Besides, why should the random collapse of different objects create a logical and orderly universe?
Many Mind interpretation of David Albert and Barry Loewer (Jonathan Allday 2009) suggests that collapse happens in the mind of the observer. According to the theory, each individual has infinite number of nonphysical minds to accommodate every possible outcome of superposition of states. The theory accepts one superposed universe, However it suggests that collapse to each state happens in one mind of the many mind individuals. Amongst other problems the theory requires a disconnection between mind and brain. Finding a physiological explanation for the theory is almost impossible.
In the quest to solve this riddle of the century, every possible road has to be explored. Above, I tried to show that our perception cannot be regarded as flawless and it is possible that classical version of reality is merely an invention of our brain. In this view while the world is in superposition of states, our neuronal network portrays a classical world in our perception. This neuronal network is shaped by human genes and later on is modified by parental, social programming and individual experiences.
The left-brain/right-brain dichotomy or, more accurately, processed versus unprocessed data, and the mechanism by which we form perception may provide a solution. The dichotomy suggests that classical-level perception is partly constructed by our judgmental left hemisphere. However, the perception of the suppressed but unbiased right hemisphere is more in line with quantum-mechanical principles. Our classical perception may be just an approximation of the actual realty out there. Looking outside the box to get a broader view is necessary for the next step in the evolution of the human race. Perhaps we need to pay more attention to the scope of right brain.
According to model-dependant realism introduced by Hawking and Mlodinow, our brains interpret the input from our sensory organs and make a model of outside world. We form mental concepts of different objects accordingly. These mental concepts are the only reality we can know (Hawking and Mlodinow 2010).
However, by departing from classical models and building new models based on quantum mechanical principles we can obtain a deeper understanding of reality. We have done it in industry and already enjoyed a big leap in technology. We just need to follow the suite in everyday perception as well. The left-brain/right-brain dichotomy or, more accurately, processed versus unprocessed data, and the mechanism by which we form perception may provide the answer.
Here, I have tried to speculate on a hypothesis and offer some cues. Once again, I must mention that this is an oversimplification of the brain’s actual hemispheric functions. Brain physiology is complex and subject to ongoing research and development. Many brain functions are the product of neuronal circuitries collaborating in different segments of brain and in different hemispheres.
Although this concept is in its infancy and lacks the graces of a fully developed theory, it has the potential to answer many of the major paradoxes and therefore deserves open discussion and debate.