Does the Uncertainty Principle Refute Realism?

Does the Uncertainty Principle Refute Realism?
By: Doug McManaman

Some scientists reason that although we can never measure the electron with perfect accuracy, we can determine what we will observe-a wave (if we refine our motion measurement) or a particle (if we refine our position measurement). What we observe depends on how we observe it. The observed phenomenon depends on the observation, and therefore on the observer. And so it seems that quantum theory raises doubts about one of the most deeply held articles of scientific faith-the belief in an objective world that is independent of our observations. Quantum theory and the uncertainty principle tell us that we cannot picture nature but can only predict the results of specific experiments-and these results will depend on how we choose to perform our experiments. Not only are we blind to the workings of nature, but even our brief glimpses are of no objective, independent reality but of a subjective, observer-determined world.

The above is a typical example of trying to draw philosophical conclusions from scientific knowledge. Firstly, the existence of the external world and its having meaning independently of my observation of it is not an article of faith. Faith involves accepting as true something somebody tells us because we have evidence that the speaker is well informed about the subject and is honest. Knowledge of the external world's existence does not require the mediation of another person. The idea that the existence of the objective world is an article of faith only shows that the author of those words has not really freed himself from the influence of Descartes and is still working within the framework of epistemological idealism.[1]

Experiment is a special form of experience.[2] In order to be apprehended, an experiment must always be experienced. Experience is more ultimate and indeed prior to experiment, and if experience is unreliable, then experiment is also unreliable. In this light consider the following: one begins with an experiment (a controlled experience) and through that experiment establishes a premise, namely, that we cannot be certain of the position and momentum of an electron at the same time. Our observation of the electron changes its position. And since it is assumed that the visible world is determined by the microscopic or submicroscopic (we will come back to this later), it isn't difficult to see how the idea that "our observation of the world changes the world" should proceed therefrom rather naturally. The conclusion is that we do not see the world as it is in itself, that is, objectively. The observer changes what he observes.

But that means that our first premise cannot be taken seriously, because it was established by an experiment, which is a controlled experience, and experience is unobjective, according to the above text. Therefore, we cannot conclude that realism is false. We cannot conclude anything about the relationship between the observer and the external world; for we cannot conclude anything about the observer and the electron. How can I act as a realist in order to establish my first premise, and then proceed to deny realism? If I end up by denying realism, I must also deny my first premise. If I deny my first premise, I cannot conclude that realism is naive.

In the September 2, 1927 edition of the New York Times, Waldemar Kaemppfert wrote:

To measure the properties of a particle such as an electron, one needs to use a measuring device, usually light or radiation. But the energy in this radiation affects the particle being observed. If you adjust the light beam to accurately measure position, you need a short-wavelength, high-energy beam. It would tell you position, but its energy would throw off the momentum of the particle. Then, if you adjust the beam to a longer wavelength and lower energy, you could more closely measure momentum, but position would be inaccurate.

As you can see from the above text, it isn't our observation that changes anything, it is the energy in the radiation that affects the particle being observed. This is a long way from the Idealism of Immanuel Kant.[3]

Notes

¹ See F. F. Centore, Being and Becoming. A Critique of Post-Modernism (New York:. Greenwood Press, 1991), 71-83.

²V.E. Smith, Philosophical Physics (New York:. Harper & Brothers, 1950), 16-17, 141-144.

³See Paul Feyerabend, "Quantum theory and our view of the world" in Physics and our view of the World, ed. Jan Hilgevoord (Cambridge: Cambridge University Press, 1994) 149-168. For an idealist perspective on the quantum reality question, see Nick Herbert, Quantum Reality. Beyond the New Physics (New York: Doubleday, 1985), 117-121.