For some, this is a controversial book. Why? After all, the experimental results we report are completely undisputed. And the explanations of them with quantum theory are completely standard. It’s the book’s focus on the quantum enigma, the mystery beyond the physics, that’s controversial.

Many physicists dismiss this mystery as irrelevant for all practical purposes, and best not emphasized. It displays physics’ encounter with consciousness. Its discussion can be embarrassing. It’s been called our “skeleton in the closet.”

One concern is that some people, seeing the solid science of physics linked to the mystery of the conscious mind, might become susceptible to all sorts of pseudo-scientific nonsense. We physicists can also be uncomfortable seeing our discipline involved with anything so “unphysical.”

What’s unphysical? From its inception, quantum theory involved the observer. To account for the demonstrated facts, quantum theory has the observation of an object instantaneously influencing the behavior of other distant objects–even if no physical force connects them. Quantum theory also has the existence of an object at the particular place where it is observed become an actuality only upon its observation.

But what constitutes an “observation”? It’s not clear. Moreover, as quantum phenomena are now being demonstrated with ever-larger objects, this “quantum measurement problem” gets increasing attention, both by physicists and in popular treatments.

“Observation” cannot be separated from “awareness,” and therefore from “consciousness.” These two concepts themselves involve some mystery. We must be careful. Any broad-ranging discussion of physics’ encounter with consciousness walks the edge of a slippery slope. We therefore work to distinguish the demonstrated facts from speculation (and, of course, from pseudo-science).

But the issues raised by the demonstrated facts intrigue and invite speculation beyond the established physics. Several interpretations of what quantum mechanics is telling us about our world (and about us?) currently contend. Some interpretations are wild.

Since quantum mechanics works well for all practical purposes, some physicists vociferously argue that the mysteries are irrelevant. They should therefore not be emphasized to a lay audience–or even to physics students. Remarkably, the demonstrated facts are quite understandable without any background in physics. Non-physicists can decide, and even speculate, for themselves.


Here are some comments by experts in the foundations of quantum mechanics illustrating the controversy. Some, on both sides, have Nobel Prizes in physics.

First, Arguing that here is no problem:

Tom Banks: “I think there have been clear mathematical arguments given, which show that macroscopic objects (including Schrodinger’s poor cat) made of constituents with local interactions, obey the rules of classical probability theory.  There is nothing more mysterious in QM than that.”

Murray Gell-Mann: “The universe presumably couldn’t care less whether human beings evolved on some obscure planet to study its history; it goes on obeying the quantum mechanical laws of physics irrespective of observation by physicists.”

N. G. van Kampen: “Quantum mechanics provides a complete and adequate description of the observed physical phenomena on the atomic scale. What else can one wish?…The scandal is that there are still many articles, discussions, and textbooks, which advertise various interpretations and philosophical profundities…Many physicists have not yet learned that they should adjust their ideas to the observed reality rather than the other way round.

Christopher Fuchs and Asher Peres: “Quantum theory needs no ‘interpretation.'”…We need nothing more than the fully consistent theory we already have.”

On the other hand, arguing that there is a problem:

J. M. Jauch: “The interpretation [of quantum mechanics] has remained a source of conflict from its inception. . . . For many thoughtful physicists, it has remained a kind of ‘skeleton in the closet.'”

Albert Einstein: “I cannot seriously believe in [quantum theory] because. . . physics should represent a reality in time and space, free from spooky actions at a distance.”

Frank Wilczek: “The relevant literature [on the meaning of quantum theory] is famously contentious and obscure.  I believe it will remain so until someone constructs, within the formalism of quantum mechanics, an ‘observer,’ that is, a model entity whose states correspond to a recognizable caricature of conscious awareness.”

John Bell: “It is likely that the new way of seeing things will astonish us.”

Andrei Linde: “Will it not turn out, with the further development of science, that the study of the universe and the study of consciousness will be inseparably linked, and that ultimate progress in the one will be impossible without progress in the other?”

This argument on whether or not there is a problem brings up an analogy that accords with our own bias. A couple is in marriage counseling. The wife says, “There’s a problem in our marriage.” Her husband disagrees, saying, “There’s no problem in our marriage.” The marriage counselor knows who’s right.