In this brief article, I would like to stimulate your curiosity about a booklet I have recently written, in which I explore, in a non-technical (but conceptually accurate) way, some aspects of the important theme of observation in quantum mechanics, trying to shed some light on a key question, still quite controversial, which is the one of the very nature of the observational process. I do so by answering the following question:
Is the observation of a physical system always amenable to a process of discovery of a reality that was already existing, before the observation was carried out, or, in certain circumstances, can it be traced to an act of pure creation (or destruction), that is, to a process through which what is observed is literally brought into existence (or annihilated) by the process of observation as such? And if so, what is at the origin of such creative (destructive) process?
This is obviously a key question, both for the research in physics and for a broader understanding of the relationship between the human consciousness and the reality that is the subject of her/his experience.
What exactly is our role as observers-participators of the reality in which we are immersed? Are we the discoverers of this reality or, unbeknownst to us, are we also its co-creators?
From the point of view of physics, these kinds of questions have emerged with the birth of one of the greatest scientific revolutions of our time: quantum mechanics (today more generally referred to as quantum physics). It is indeed in this context that in the early decades of last century a more thorough and refined investigation of the central role of the observing subject, in the characterization of the properties of a physical system, became necessary, in a way which was totally unexpected.
Indeed, the founding fathers of quantum physics did realize, during the construction of this baffling theory, that the reality of physical systems seemed to depend on the manner in which the investigators were operating on them, in the sense that it was not anymore possible to attribute certain properties to a physical system, independently of the acts of observation that it was conceivable to execute on it.
From this apparently new situation, a question of purely metaphysical nature emerged, about the nature of the reality in which we live, and more specifically about the validity of the hypothesis of realism, which until then had been widely shared by most physicists and philosophers of science.
Roughly speaking, we can define the idea of realism as the hypothesis that “there is a reality out there,” whose existence is entirely independent of the observing subjects, and that this reality, precisely because autonomously existing, would be knowable and describable in an objective way, for example through the construction of appropriate scientific theories.
To put it in more suggestive terms, according to the view of realism, it would always be possible, at least in principle, to speak about the reality regardless of the mind of the observing subject who studies and contemplates it.
Before the advent of quantum physics, the idea of realism, at least in physics, imposed by itself, and this for one simple reason: the observing subject did not appear at any level in the physical theories. In other words, everything we knew about the physical systems and their evolution could be described independently from the existence of those who studied them: that the systems were observed or not, this did not alter in any way their properties and the way in which these properties evolved in time.
The characteristics of the orbit that the Moon describes around the Earth, for example, remain such irrespective of the fact that terrestrial astronomers point their telescopes in order to observe it. And that is why Johannes Kepler, in his famous laws describing the motions of the planets, made no mention of a possible influence on these motions caused by the astronomers’ activities.
The planets go through the cold and quiet outer space totally careless of the bustling human activity on the surface of planet Earth!
But with the advent of quantum physics, all this suddenly changed. In fact, in the description of microscopic systems, physicists realized that it was no longer possible to describe these entities without mentioning in their theories the very process of observation, namely the effects that such a process could produce on the observed systems (in physics, one mostly uses the term measurement, instead of observation, but the meaning is, in ultimate analysis, exactly the same: to measure a physical quantity means, in fact, to observe its value in practical terms).
This strange “pitch invasion,” which meant that scientists were seeing themselves — as in the mirror — represented in their own physical theories (not as the authors, but as an integral part thereof), has obviously undermined the very assumption of realism, on which rested the whole edifice of scientific inquiry, aimed at searching for an objective view of reality.
In fact, without the possibility of separating the scientists, in their role of investigating and observing subjects, from the object of their investigation and observation, how was it possible to continue to give a meaning to the very concept of reality?
How was it possible to speak of reality if it could not be described independently of the thinking minds of those who were studying it?
What I will try to explain in my booklet, is that even though quantum physics has revealed to us some very strange and unexpected aspects of the profound nature of physical entities, particularly at the microscopic level, and although, undoubtedly, it has shown to us that it is not possible to generally describe a physical system regardless of the active role played by the observer in this description, not for this we must give up the idea of realism, i.e., the idea of a reality independent of the conscious mind activity of the observer.
To do this, however, it will be necessary to abandon that form of naive realism, of a classical kind, which is based on the prejudice that the physical entities populating the world should necessarily always possess, in actual terms, all the properties that possibly characterize them, so that the result of whatever process of observation must necessarily always be, in principle, predictable and predetermined.
This form of naive realism needs to be reformed in a more articulated and mature concept of realism, which sees in the creation-discovery binomial the key to a proper understanding of the role of the observer.
I hope I have captured your curiosity!
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