3.5 THE ONTOLOGICAL QUESTION: WHAT, AFTER ALL, IS AN ELECTRON?
For Einstein the objective reality of a component of matter was self-evident. Consequently, a theory which could not fully capture that fact was bound to be either wrong or, at best, incomplete.
For the same real state of the system it is possible therefore to find (depending on one’s choice of measurement performed on ) different types of wave function. One can escape from this conclusion only by either assuming that the measurement of telepathically changes the real state of or by denying altogether that spatially separated entities possess independent real states. Both alternatives appear to me entirely unacceptable.
Albert Einstein, Autobiographical Notes, (1946)
For the younger generation, however, the reality of an electron was far less important than the capacity of the new theory to capture the experimental data obtained in observing it. According to them, the difficulty Einstein and Schrödinger found in dealing with the implications of the theory merely demonstrated the difficulty the older generation had in dispensing with classical conceptions. Still, with a theory as young as quantum mechanics, a threat such as the one so brilliantly distilled by Einstein in his EPR paper, was bound to raise concerns. Until such time as the theory was incontestably established, one ignored the issue at one’s peril. Once however the theory did gain general acceptance through its unqualified capacity to explain atomic observations, the issues concerning the physical meaning of its objects could safely be pushed aside. To ask questions concerning the Being of an electron, for instance, was simply not allowed because one could not possibly answer such questions experimentally:
Unless a thing can be defined by measurement, it has no place in a theory.
Richard Feynman, Lecture on Physics, 1965
This was a brilliant defensive maneuver which allowed quantum mechanics to develop un-encumbered by philosophically troublesome questions. But, like all defensive positions, it is penetrable; it could not keep unanswered questions from claiming attention even to this day, almost one hundred years later. First, if experimental measurement of atomic entities is the ultimate arbiter of what description of them is to enter through the front door of theory, what exactly are these experiments observing in the first place? Second, in what way are experiments observing an electron which has no objective reality differ from experiments observing an object of experience, say a pebble, which does? Third, if quantum physics describes a non-local universe, in which “spatially separated entities do not possess independently real states”, in what sense does matter consist of corpuscular components? And fourth, if the constituents of matter are not objectively real as quantum theory seems to suggest, then how and from whence can a material object made out of them obtain its reality? Perhaps, now that quantum mechanics proved itself so successful in accounting for phenomena related to the inside of things and is thus no longer as vulnerable to ontological questioning as it once was, the time has finally come to abandon defense and confront those questions directly.
We suggested at the beginning of Chapter 2 that we shall be able to confront these ontological questions if we let Einstein’s EPR paper be our guide. The dichotomy between physical reality and theoretical completeness so clearly established there by Einstein, shows us the way. Indeed, since quantum theory has proved itself to be a complete description of those observations we care to perform on atomic entities, then those entities cannot be real in the sense in which Einstein defined that term, that is, as something that is considered to be independent of its being observed. On the other hand, they cannot be nothing at all either because the corpuscular theory insists that matter is constituted of them and clearly matter is something rather than nothing. What then are they? Well, by Einstein’s argument, they must be something whose very Being is tied up with the process of observing them. If we begin by taking the electron to be real, such an intimate relationship between observation and observed can only be described as uncontrollable disturbance of the latter brought about by the measuring equipment used in the former. Under the circumstances, the better part of wisdom would indeed be to sequester the issue from inquiry as the community has been consistently doing from the beginning and the question what is an electron would then remain closed. If, on the other hand, we take the electron as something that is somehow dependent on its being observed, not only is there no bar to ignoring Feynman’s dictum but there is in fact a positive duty to inquire into how observation determines the Being of the observed.
We progress with that inquiry if we recognize that quantum mechanics is the formal representation of that dependency and ask instead: What is the Being of an entity whose behavior is fully described by quantum mechanics? Using the theory to thus specify the Being of its objects, rather than specifying their Being first and then declaring the theory incomplete just because it did not fit the description of its chosen object, provides the needed foothold for progress. What we propose to do in the next chapter therefore is travel back in time to the beginning when science emerged from human experience and examine carefully the origin of our ontological conceptions concerning atomic entities as well as the role that observation may have played in their formation.