Quantum mechanics needs no consciousness (and the other way around)


Post by Arbitrageur at ATS.
Quantum mechanics needs no consciousness (and the other way around)

It has been suggested that consciousness plays an important role in quantum mechanics as it is necessary for the collapse of wave function during the measurement. Furthermore, this idea has spawned a symmetrical proposal: a possibility that quantum mechanics explains the emergence of consciousness in the brain. Here we formulated several predictions that follow from this hypothetical relationship and that can be empirically tested. Some of the experimental results that are already available suggest falsification of the first hypothesis. Thus, the suggested link between human consciousness and collapse of wave function does not seem viable. We discuss the constraints implied by the existing evidence on the role that the human observer may play for quantum mechanics and the role that quantum mechanics may play in the observer’s consciousness.

The idea of consciousness being involved in quantum mechanics dates back to Von Neumann in the 1930s, but the idea was more recently popularized by Wigner. However people citing Wigner may not realize he dropped this opinion in his final years:

Wigner popularized this link between consciousness and collapse of wave function passionately (Esfeld, 1999). Wigner suggested that “It is the entering of an impression into our consciousness which alters the wave function.” and “It is at this point that consciousness enters the theory unavoidably and unalterably.”(cited from Shimony, 1963). Importantly, however, Wigner dropped this opinion completely at his final years (Esfeld, 1999).

The paper goes on to cite heated debates about the subject of consciousness in quantum mechanics that span decades, and notes that:

Many of them address this issue from the philosophical point of view. Although they went to deep and interesting levels and brought up exciting ideas about fundamental aspects of the relationship between the mind and the physical world, those profound analyses failed to reach a simple and clear conclusion that would be widely accepted.

Since philosophy wouldn’t ever resolve this question, an empirical approach was needed:

In the present paper, we do not aim to provide another philosophical argument. Instead, we attempt to address this issue from an empirical perspective. We reformulate von Neumann’s hypothesis as an empirically testable problem. We then attempt to falsify the hypothesis on the basis of the existing empirical evidence, as already suggested elsewhere (Mandel, 1999; Zeilinger, 1999a; Brukner and Zeilinger, 2002).

The paper then discusses experimental evidence suggesting conscious perception is not required to explain quantum mechanics observations:

We first derived a proposition about the relationship between the collapse of thewave function and conscious perception. Our subsequent analysis lead to the conclusion that this proposition is already disproved by the existing empirical results, which forces us to conclude tentatively the following: Conscious access to the information about the outcome of a measurement of a quantum state is not necessary for the collapse of wave function– –conclusion similar to those suggested else- where (Mandel, 1999; Zeilinger, 1999a; Brukner and Zeilinger, 2002).

The analysis in the paper is a bit technical, but for a simplified explanation see the video below which explains the experimental results in layman terms and the implications for consciousness.

Quantum Eraser Explained | Quantum Mechanics ep 5

In this video I’ll explain the basics of the quantum eraser experiment and then explain what it means. If you want to understand the full experimental set up, check out my previous video: youtu.be…

What seems odd is that some people try to cite the quantum eraser experiment as proof that consciousness is needed in quantum mechanics but it actually shows the opposite, that it’s not. That’s ok, you can have other reasons to feel special about yourself, without the need to feel that the universe revolves around you because of your consciousness.

Here is a pretty good technical explanation of the implications of the quantum eraser experiment. Most of the “spooky” misinterpretations which lead to “magic” are the result of assuming things we call “particles” must always act like particles, but a fundamental concept of quantum mechanics is that they can also behave as waves. When we consider this wave behavior, it’s much easier to interpret the results of the experiment:

The Quantum Eraser Experiment.

The aim of this set of experiments (Ref. 5) is similar to that of the Wheeler Delayed-Choice Experiment in that if one assumes the existence of particles, then one gets into causality (and locality) troubles. Before explaining the experiments, we should reiterate that there is No Evidence for Particles; all the particle-like properties of matter can be shown to be properties of the wave function. So our view is that, as in the Wheeler delayed-choice experiment, one is using an unsupported idea—particles—to derive seemingly surprising results.

So we do see “particle-like” behavior, but even this is the result of the wave function.

If one postulates particles, and if one requires that each particle be in a definite state at each instant, then experiment 3 seems to require action-at-a-distance between the two particles. And experiment 4 seems to require retroactive action-at-a-distance. But if one postulates no-particle quantum physics, the experiments simply verify the correlations predicted by quantum physics between the two entangled photon-like wave functions.

It took me a while to figure out that when physicists say “particle” or “particle-like” they are not necessarily inferring marble like objects though this is the impression one might get from seeing sources over-simplified for popular consumption. Quantum mechanics has the wave function at its heart and the key to understanding the quantum eraser is to stop thinking of “particles” as little marbles, and start thinking of them as manifestations of the wave function. The sooner you realize that a photon has very little in common with a small marble, the faster you’ll be able to grasp interpretations of quantum experiments using the wave function.

The paper cited at the beginning of this post concludes:

In conclusion, the available evidence does not indicate that the observer’s explicit phenomenal representation about the outcome of a measurement plays a role in collapsing the wave function. We also suggest that the observer does not serve a more fundamental function in quantum mechanics than that in the classical theory. Thus, the idea that by mere observation the experimenter creates physical reality is not viable. This supports Wigner’s opinion in his later years and promises to fulfill his hopes– –that we “will not embrace solipsism” and “will let us admit that the world really exists” (cited from Primas and Esfeld, 1997).

There are still fundamental mysteries in quantum mechanics. We have a lot of possible interpretations, and we don’t know which interpretation is correct, but it does appear that consciousness is not fundamentally required for the currently viable possible interpretations.


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