Although quantum mechanics has been around since before World War II, many scientists refer to it as the new physics. They suggest that it conveys deep insights into the nature of consciousness, insights that confirm the mystical teachings of yogis and herald a new age of enhanced awareness.
But does quantum mechanics (or QM) truly reveal anything about consciousness and its role in nature? A close look at the theory shows that it doesn’t. Attempts to analyze the role of “the observer” in QM show that the theory is plagued with persistent conceptual problems. And when we try to bring consciousness into the picture, those problems simply get worse.
To see why this is so, let’s consider an idealized experiment, the simple “delayed-choice split-beam experiment” proposed by physicist John Wheeler. As shown in the figure, this experiment involves a light source, S, that fires single photons of light at a half-silvered mirror, A. This mirror divides the light equally into two beams, which then reflect from two fully reflective mirrors, Band C. The two beams mix at a second half- silvered mirror, D.
Two photodetectors, Eand F, are mounted on a sliding base so they can be placed in position (1) or (2). In position (1) the two detectors respond to the light after the beams mix at D. With strong monochromatic light, the detectors seem to register the effects of light-wave interference between the two beams. The same thing happens when the light is so weak that photons emerge from the source only one at a time: let many successive photons go through, and one photodetector will count significantly more photon hits than the other. We account for the difference in hitting rates by assuming that each photon splits into two waves, which interfere with one another at D.
When placed in position (2), the two photodetectors reveal a curious phenomenon. After a photon emerges from the source, either Eregisters a hit or Fregisters a hit, but not both. So in this arrangement it appears that the photons do not split. Either a photon follows the right-hand path (SABE) and hits photodetector E, or it follows the left-hand path (SACF) and hits detector F. We never see both Eand Fresponding to the same photon.
If this is true, it means the photons are arriving one at a time. How then could they build up an interference pattern at D? Interference requires two waves to interfere, and surely this is not possible if the photons must approach Done by one, by one path or the other. It seems, then, that QM is saying contradictory things about how the photons behave.
Niels Bohr, a pioneer quantum physicist, resolved that problem by saying this: If the detectors are in position (1) they respond only to light coming through D, the two beams interfering with one another. The detectors don’t tell us that each photon must follow only one of the two paths. And if the detectors are in position (2) they block the photons from reaching D, and therefore we see no split photons interfering. So we can suppose that in arrangement (1) the photon seems to split but in arrangement (2) it doesn’t. Bohr concluded that whether or not the photon seems to split depends on how we set up the observational apparatus. What we are prepared to observe affects what seems to happen.
Wheeler made Bohr’s interpretation more striking by noting that one may position the photodetectors after the photon has left mirror A, which splits the beam. We might think that at this point either the photon has split or it has followed one of the two paths, through Bor C.
According to Wheeler’s analysis, whether we see interference or see photons coming on separate paths still depends on the position chosen for the photodetectors.
Does this mean that the photon has split or stayed single as a consequence of a choice made later? Wheeler says no. He concludes, “No phenomenon is a phenomenon until it is an observed phenomenon.” In other words, one can’t say anything about the photon before the observation, which, so to speak, brings the observed phenomenon into existence. Wheeler generalizes on this by saying, “The universe does not ‘exist, out there.’ … It is in some strange sense a participatory universe.”
Introducing Consciousness
Now, this might seem to tell us something profound about consciousness. It might seem to suggest that consciousness somehow plays a crucial role in the phenomena of nature.
But this is not the case. First of all, what is an “observer” in QM? In every case the observer is a physical device. Here the observer is a photo detector, which might consist of a photographic plate, an electronic photocell, or even the retina of someone’s eye. Wheeler’s analysis doesn’t mention whether or not a conscious human being ever becomes aware of what the photodetectors are doing. We don’t think of a photodetector itself as conscious (even when it is a retina), and in analyzing the experiment the idea of consciousness plays no role. The strange phenomena predicted by Wheeler’s theory tell us nothing about consciousness.
Still, some physicists have tried to introduce consciousness into their analysis of quantum mechanical experiments. For example, John von Neumann suggested that the time when a phenomenon becomes an observed phenomenon can be delayed until the experimental data is perceived by the “abstract ego” of the human observer. It almost seems as though von Neumann’s analysis of quantum phenomena has led him to posit a nonphysical soul.
But von Neumann’s line of thought requires him to postulate that detectors Eand Fin position (2) go into a kind of schizoid state in which Efires but not F, and Ffires but not E. Furthermore, the brain of the human observer must go into a state in which it registers Efiring but not F, and Ffiring but not E.
This is the unsatisfactory state of affairs that Erwin Schrodinger discussed in his “cat paradox,” in which quantum phenomena give rise to a cat that is simultaneously dead and alive. Wheeler avoids this problem by cutting short his analysis at the photodetectors and not bringing consciousness into the picture.
What happens if we try to introduce a universal observer—the Supersoul as described in Bhagavad- gita? One might think that since the Supersoul is all- seeing, He must know whether the photon splits at mirror Aor follows the path to Bor Cwithout splitting. But if quantum mechanics is correct, what the Supersoul sees must conform to the observations allowed by the arrangement of the physical detectors. According to QM, a phenomenon is not a phenomenon until physical devices “observe” it. If we posit a nonphysical observer who can see things independently of the physical apparatus, we get into trouble with the quantum theory.
A Deeper Theory of Nature
So what can we say about quantum mechanics and consciousness? Even though QM has an excellent record of accurately predicting certain physical phenomena, it is a physical theory afflicted by serious conceptual difficulties. I would propose that QM is not a fully correct description of physical reality, and a better theory may eventually replace it. Wheeler declares that he is sticking with the standard quantum theory because it is “battle-tested.” But classical mechanics is also battle-tested, and in the late nineteenth century many expert physicists thought it was approaching perfection. Then, in the twentieth century, physics was revolutionized, first by relativity theory and then by quantum mechanics.
A great deal of evidence points to the existence of phenomena contrary to what quantum mechanics predicts. For example, many experiments show that the will of a human observer can influence physical events without the aid of physical actions initiated by the human body. A group of researchers headed by Robert Jahn of Princeton University has performed many experiments of this kind. The findings of this group contradict the predictions of the standard quantum theory, and I can attest from my own analysis that they deserve to be taken seriously.
The Jahn experiments involve small effects observable only by careful statistical analysis. Other reported phenomena, however, strongly violate the known laws of physics. For example, Ian Stevenson has accumulated and carefully analyzed a large body of data suggesting that a child will sometimes accurately remember events that took place in the life of a particular deceased person. These data are consistent with the idea of reincarnation, and by the known laws of physics they are unexplainable. Like the Princeton results, they also directly involve human consciousness.
I suggest we look forward to the unfolding of a deeper theory of nature, one that goes beyond QM, just as QM goes beyond classical physics. Consciousness and phenomena directly involving consciousness should play an integral role in this genuinely new physics. Only with such a theory shall we truly be able to understand in what sense we live in a “participatory universe.”
