Prima facie, what Einstein and his colleagues argued was that under ideal conditions, observation (includes measurement) functions like a mirror reflecting an independently existing, external reality. The specific criterion for describing reality characterizes it in terms of objectivity understood as independence from any direct measurement. This implies that, when a direct measurement of physical reality occurs, it merely passively reflects rather than actively constitutes the object under observation. It further implies that ideal observations not only reflect the state of the object during observation, but also before and after observation just like a photograph taken. It has a separate and fixed identity than the object whose photograph has been taken. While the object may be evolving in time, the photograph depicts a time invariant state. Bohr and Heisenberg opposed this notion based on the Kantian view by describing acts of observation and measurement more generally as constitutive of phenomena. More on this will be discussed later.
The fact that our raw sense impressions and experiences are compatible with widely differing concepts of the world has led some philosophers to suggest that we should dispense with the idea of an “objective world” altogether and base our physical theories on nothing but direct sense impressions only. Berkeley expressed the positivist identification of sense impressions with objective existence by the famous phrase “esse est percipi” (to be is to be perceived). This has led to the changing idea of “objective reality”. However, if we can predict with certainty “the value of a physical quantity”, it only means that we have partial and not complete “knowledge” – which is the “total” result of “all” measurements – of the system. It has not been shown that knowledge is synonymous with reality. We may have the “knowledge” of mirage, but it is not real. Based on the result of our measurement, we may have knowledge that something is not real, but only apparent.
The partial definition of reality is not correct as it talks about “the value of a physical quantity” and not “the value of all physical quantities”. We can predict with certainty “the value of a physical quantity” such as position or momentum, which are classical concepts, without in any way disturbing the system. This has been accepted for past events by Heisenberg himself, which has been discussed in latter pages. Further, measurement is a process of comparison between similars and not bouncing light off something to disturb it. This has been discussed in detail while discussing the measurement problem. We cannot classify an object being measured (observed) separately from the apparatus performing the measurement (though there is lot of confusion in this area). They must belong to the same class. This is clearly shown in the quantum world where it is accepted that we cannot divorce the property we are trying to measure from the type of observation we make: the property is dependent on the type of measurement and the measuring instrument must be designed to use that particular property. However, this interpretation can be misleading and may not have anything to do with reality as described below. Such limited treatment of the definition of “reality” has given the authors the freedom to manipulate the facts to suit their convenience. Needless to say; the conclusions arrived at in that paper has been successively proved wrong by John S. Bell, Alain Aspect, etc, though for a different reason.
In the double slit experiment, it is often said that whether the electron has gone through the hole No.1 or No. 2 is meaningless. The electron, till we observe which hole it goes through, exists in a superposition state of equal measure of probability wave for going through the hole 1 and through the hole 2. This is a highly misleading notion as after it went through, we can always see its imprint on the photographic plate at a particular position and that is real. Before such observation we do not know which hole it went through, but there is no reason to presume that it went through a mixed state of both holes. Our inability to measure or know cannot change physical reality. It can only limit our knowledge of such physical reality. This aspect and the interference phenomenon have been discussed elaborately in later pages.
If, we accept the modern view of superposition of states, we land in many complex situations. Suppose the Schrödinger’s cat is somewhere in deep space and a team of astronauts were sent to measure its state According to the Copenhagen interpretation, the astronauts by opening the box and performing the observation have now put the cat into a definite quantum state; say find it alive. For them, the cat is no longer in a superposition state of equal measure of probability of living or dead. But for their Earth bound colleagues, the cat and the astronauts on board the space shuttle who know the state of the cat (did they change to a quantum state?), are still in a probability wave superposition state of live cat and dead cat. Finally, when the astronauts communicate with a computer down on earth, they pass on the information that is stored in the magnetic memory of the computer. After the computer receives the information, but before its memory is read by the earth-bound scientists, the computer is part of the superposition state for the earth-bound scientists. Finally, in reading the computer output, the earth-bound scientists reduce the superposition state to a definite one. Reality springs into being or rather from being to becoming only after we observe it. Is the above description sensible?
What really happens is that the cat interacts with the particles around it – protons, electrons, air molecules, dust particles, radiation, etc, which has the effect of “observing” it. The state is accessed by each of the conscious observers (as well as the other particles) by intercepting on its/our retina a small fraction of the light that has interacted with the cat. Thus, in reality, the field set up by his retina is perturbed and the impulse is carried out to the brain, where it is compared with previous similar impressions. If the impression matches with any previous impressions, we cognize it to be like that. Thereafter only we cognize the result of the measurement: the cat is alive or dead at the moment of observation. Thus, the process of measurement is carried out constantly without disturbing the system and evolution of the observed has nothing to do with the observation. This has been elaborated while discussing the measurement problem.
Further someone has put the cat and the deadly apparatus in the box. Thus according to the generally accepted theory, the wave-function has collapsed for him at that time. The information is available to us. Only afterwards, the evolutionary state of the cat – whether living or dead – is not known to us including the person who put the cat in the box in the first place. But according to the above description, the cat, whose wave-function has collapsed for the person who put the cat in the box, again goes into a “superposition of states of both alive and dead” and needs another observation – directly or indirectly through a set of apparatus – to describe its proper state at any subsequent time. This implies that after the second observation, the cat again goes into a “superposition of states of both alive and dead” till it is again observed and so on ad infinitum till it is found dead. But then the same story repeats for the dead cat – this time about his state of decomposition!
The cat example shows three distinct aspects: the state of the cat, i.e., dead or alive at the moment of observation (which information is time invariant as it is fixed), the state of the cat prior to and after the moment of observation (which information is time variant as the cat will die at some unspecified time due to unspecified reasons), and the cognition of these information by a conscious observer, which is time invariant but about the time evolution of the states of the cat. In his book “Popular Astronomy”, Prof. Bigelow says; Force, Mass, Surface, Electricity, Magnetism, etc., “are apprehended only during instantaneous transfer of energy”. He further adds; “Energy is the great unknown quantity, and its existence is recognized only during its state of change”. This is an eternal truth. We endorse the above view. It is well-known that the Universe is so called because everything in it is ever moving. Thus the view that observation not only describes the state of the object during observation, but also the state before and after it, is misleading. The result of measurement is the description of a state frozen in time, thus a fixed quantity. Its time evolution is not self-evident in the result of measurement. It has any meaning only after it is cognized by a conscious agent, as consciousness is time invariant. Thus, the observable, observation and observer depict three aspects of confined mass, displacing energy and revealing radiation of a single phenomenon depicting reality. Quantum physics has to explain these phenomena scientifically. We will discus it later.