A bigger issue may be the introduction of a conscious, self-aware observer into the processes of nature at a very fundamental level. The whole idea of measurement seems to require someone to do the measuring. Given the concept of wave function collapse, the act of measurement has a profound effect on nature itself. If no one cares to measure the position of an electron, its wave function evolves differently than if someone does measure it.
The reason this is a problem is that it threatens our concept of objective reality. The very framework of science assumes a reality that exists outside of and separate from the scientists who study it. For some people, this is an obvious and simple fact, while for others it is still open to debate. But for science to work in the way it usually works, we must believe that a physical reality exists even when we are not looking. Certainly the moon continues to exist even when we can’t see it (as at the “New Moon” phase), right? None of the properties of the moon should depend on whether or not we observe or measure them.
ATOM TRAP
Since it is often a source of confusion, we need to clearly distinguish between two kinds of reality. This distinction is related to the object being observed, and the subject that is doing the observing. “Objective” reality refers to something real that exists independently of any observers, and thus appears exactly the same to any number of different observers. In our vast world, however, there are some things that various people can’t agree on. Such realities are “subjective,” since they depend on the subject’s own viewpoint.
At the quantum level, if the very act of observation changes the thing being observed, then what chance do we have of different observers getting the same result when they try to measure some physical quantity? Unless multiple observers can agree on their observations, it is difficult for us to determine what is objectively real. In the Copenhagen interpretation, every observation causes a radical change in a wave function, and the wave function contains everything that can be known about a particle. This would seem to be a major assault on a cornerstone of science as a way of knowing.
QUANTUM QUOTE
[W]e have to remember that what we observe is not nature in itself but nature exposed to our method of questioning.
—Werner Heisenberg
Indeed, one of the biggest challenges of the Copenhagen interpretation has been described as the “measurement problem.” The act of measurement or observing the state of a system plays a crucial role in this scheme. What exactly do we mean by a measurement? And what actually happens when a measurement occurs?
Proponents of the Copenhagen interpretation would say that the act of measurement causes a collapse of the wave function. At the very moment a measurement is made, the wave function, which may have contained the full range of possibilities (superposition), is replaced by a single and pure quantum state. Moreover, from the experimenter’s point of view, this single state appears to be the only possibility that corresponds to the result of the measurement. We will investigate some of the bizarre implications of this seemingly obvious statement in the next section.
MAX BORN
If Max Planck was the father of quantum physics, then Max Born was its godfather. He founded the institute in Goettingen where many of quantum physics’ young guns learned their trade. It was here that, after reviewing the insightful but somewhat disorganized work of a young Werner Heisenberg, he immediately identified the underlying mathematics that was later refined into Heisenberg’s matrix mechanics.
This may lead you to think Born would have stood as a nemesis to Erwin Schroedinger, given the latter’s competing version of quantum mechanics. But Born had a taste for nostalgia and was swept up by Schroedinger’s efforts to resurrect a bit of classical physics using his famous wave equation. Born only soured on Schroedinger’s work when he tried to do away with those “damned quantum jumps,” which Born rather liked.
Born’s greatest achievement was his formulation of the “Born interpretation,” the probabilistic view of the wave function that is a central pillar of the Copenhagen school. He was inspired in this regard by a footnote in one of Albert Einstein’s unpublished papers. Einstein, too, had started down this path, but eventually rejected it due to his unwillingness to accept that physics ultimately boiled down to pure chance.
For decades, godfather Born would unsuccessfully try to convert the rebellious Einstein through their famous correspondence. Spanning the years 1916 to 1954, the so-called “Born-Einstein letters” are not only a fascinating scientific exchange, but also a thoughtful reflection on a society that tore itself apart through the course of two world wars.
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