Like The Pontiff, I am always happy to receive an email from a publicist offering me a free book to review. In this case, the book was Quantum Enigma: Physics Encounters Consciousness by Bruce Rosenblum and Fred Kuttner, of UC Santa Cruz.

I have to admit, the title made me a little uneasy. There have been a great many very stupid things written about quantum mechanics and consciousness over the years, after all. It’s published by Oxford University Press, though, so I figured they can’t be total cranks, and hey, free book!

I’m happy to report that this book does not add to the tally of stupid things written about quantum mechanics and consciouness. Instead, it’s a very readable and accessible summary of the troubling role of conscious observers in quantum theory, from the origins of the theory in the early part of last century down to the present day. If anything, the authors are too cautious, going out of their way to avoid taking sides, and merely presenting the different issues and interpretations of quantum theory.

More detailed comments below the fold.

This is very much a popular-level treatment of the problem of observers in quantum mechanics– I don’t think there’s a single equation in the book, despite several mentions of Schroedinger’s equation and others. This is an admirable goal, and it shapes most of the book.

In order to explain the weirdness of quantum theory, you first need to establish a baseline of “normalcy,” explaining a bit of classical physics for contrast. Most popular books on quantum theory contain some discussion of classical physics, and for a physicist, these chpaters are often the hardest part about reading popular books on physics– they don’t tell you anything you don’t already know, and the umpteenth time you read about Newton’s Laws, it gets to be a bit of a slog. Happily, Rosenblum and Kuttner dispense of this quickly– Newton gets 16 pages, and “All The Rest of Classical Physics” a single 12-page chapter.

Actually, they do everything quickly– the entire book is just over 200 pages– so the traditional description of the historical development of quantum theory moves along just as briskly, to get to the key issue of measurement and observation in quantum mechanics (again, despite extensive discussion of wavefunctions and their meaning, they manage not to include any equations, which is fairly impressive). They also include a brief discussion of the importance of QM for modern technology, calling it the basis of one third of the modern economy. This is a nice touch, explicitly laying out why the theory is important, before diving headfirst into the weirdness.

Once they get to their main topic, the pace slows a bit, and they spend a full chapter outlining the Copenhagen Interpretation (which they equate with “Shut Up and Calculate”), and another on Schroedinger’s cat and superposition states. They present a nice outline of the Einstein-Podolsky-Rosen experiment, and a really excellent physical analogy to explain Bell’s Inequality, that I plan to copy the next time I lecture about those topics. They give brief discussions of no less than nine different interpretations of quantum mechanics, and how each deals with measurement and observation, and then close with chapters exploring the issues involved in the whole idea of “consciousness,” what role quantum mechanics might play in that, and consciousness in cosmology.

They resolutely avoid drawing any conclusions about any of this. They merely present the various interpretations and odd theories, as if all are on an equal footing. Their objectivity is amirable, but I can’t help thinking the book would’ve benefitted from a stronger stance in the final chapters.

Though they deal with some very strange and frequently misrepresented material, they do an admirable job of avoiding and even denouncing quackery. They have some harsh words for What the Bleep Do We Know?, and deny that quantum mechanics supports mysticism:

Quantum mechanics tell us strange things about our world, things that we do not fully comprehend. This strangeness has implications beyond what we generally consider physics. We might therefore be tolerant whennonphysicists incorporate quantum ideas into their own thinking– even if they do so with less than complete understanding, or even a bit incorrectly.

We are, however, disturbed, and sometimes embarrassed, by cavalier, perhaps intentional, misues of quantum ideas, as a basis for certain medical or psychological therapies (or investing schemes!), for examples. A touchstone test for such misuse is the presentation of these ideas with the implication that the notions promulgated are derived from quantum mechanics rather than merely suggested by it.

While they could be stronger in their condemnation of quantum abuse, it’s good to see a book on this topic that doesn’t veer off into total woo-woo mysticism.

Of course, any review is obliged to make a few negative comments, and there’s room for that. Some of the writing is a little uneven, with choppy little passages of short declarative sentences followed by other sections full of long and complex sentences with clauses galore. The overall effect is a bit jarring.

There are also three or four sections that are written in the form of imaginary dialogues. These desperately want to be Goedel, Escher, Bach, and, well, they’re not even close. The imaginary visit to “Neg Ahne Poc,” where quantum phenomena occur in the macroscopic world, is particularly clunky, at least to my ear. The authors seem to view this as the centerpiece of the book, and refer back to it frequently, which is a little unfortunate.

The oddest thing about the book, though, is that most of the figures (with the exception of some photographs of famous physicists, and a couple of cartoons) are hand-drawn. There’s a certain quirky charm to having the discussion illustrated by little stick figures and crude sketches of apparatus, but I’m not sure why they don’t have a single photograph of an interference pattern. The difference between particle and wave behavior comes up again and again, and every time, is illustrated by a little hand-drawn cartoon of dots on a screen. It’s not hard to find a good picture of real interference fringes, or even of single-particle interference data, so I’m slightly puzzled by this decision.

In fact, this brings me to what I consider the weakest part of the book, which is the sparse reference to experiment. Particualrly in the last couple of decades, there have been many beautiful and elegant experiments done to demonstrate the various phenomena discussed in the book, and they’re hardly mentioned here. Where important results have been confirmed by experiment, they usually mention the existence of experiments, but never present data or any detailed discussion of how the experiments were done.

I suspect that this is a conscious decision, in keeping with their desire to keep the book at a popular level, but to my mind, it weakens the book. Some of the experimental confirmations of quantum theory are so dramatic that they can easily impress non-experts, and I think the book would’ve beneftted from their inclusion. But then, I’m an experimentalist, and I would say that…

(Incidentally, I’ll sneak in a plug here for The Quantum Challenge by Greenstein and Zajonc, which has a strong focus on experiments. It’s not really a popular-level book, though, as it contains a fair number of equations (and, indeed, served as the textbook for my Quantum Optics class), but it’s an excellent presentation of the experimental evidence of quantum weirdness.)

On the whole, this is a very accessible and readable presentation of the issues involved in describing the role of the observer in quantum theory. The material presented is all on a sound theoretical basis, and it’s laid out in a way that should be comprehensible for the general reader. While it might’ve been a more exciting book had Rosenblum and Kuttner decided to advocate a particular position, their comprehensive and objective summary of the issues and interpretations involved should provide a valuable resource for any reader who would like to understand the real science behind the fuzzy area where quantum physics meets consciousness.


  1. #1 somnilista, FCD
    August 9, 2006

    Though they deal with some very strange and frequently misrepresented material, they do an admirable job of avoiding and even denouncing quackery.

    It is not clear to me why you would consider it admirable to let quackery go unchallenged. Care to expound?

  2. #2 Chad Orzel
    August 9, 2006

    It is not clear to me why you would consider it admirable to let quackery go unchallenged. Care to expound?

    They do a good job of avoiding and denouncing quackery. That is, they avoid falling into it themselves, and also have some harsh words for quacks. They’re not letting it go unchallenged.

    As far as it goes, I think that avoiding quackery is necessary for a good physics book, while denouncing it is merely a nice bonus. It’s not a book about quackery, after all, so as long as they avoid saying anything stupid themselves, I’m fine with it.

  3. #3 Rob Knop
    August 9, 2006

    where quantum phenomena occur in the macroscopic world,

    Brian Greene does that a fair amount too with his Quantum Cafe. I have to admit that I find that sort of thing a bit jarring. I suppose it’s helpful in the way that all kinds of analogies are helpful…. The problem I have with those sorts of things, though, is that we’re constantly making observations of non-collapsed states, etc., and it’s a halfway mishmash between quantum and classical. Perhaps I just know too much.


  4. #4 DavidD
    August 9, 2006

    Well I’m glad to read that they denied that quantum physics supports mysticism even if they didn’t find their way to say the same about consciousness. It sounds as if the “consciousness” in the title is something of a bait and switch, unless they meant how mind-altering it was to all classically trained physicists to try to understand quantum physics.

    Isn’t it possible to say that quantum mechanics shouldn’t have any effect on phenomena beyond a certain size? On top of that if there is a spiritual side to reality unknown to physics, a place to put whatever mind we have beyond our neurons, if any, why would quantum physics have anything to do with what might as well be another universe? I don’t know why those who know physics can’t say that quantum physics has absolutely nothing to do with consciousness, whatever consciousness is.

  5. #5 DavidD
    August 9, 2006

    Just to share a search I just did on google…

    I got my undergraduate degree in physics over 30 years ago. At that time a professor was looking into superconductivity as a model for human memory. One big problem as I looked at this – what in the brain could possibly perform as the mechanism for superconductivity did? I was wondering whatever happened to this. So I did this search on superconductivity and “human memory”. Wow! Do an awful lot of people have nothing better to do. It’s not only memory now, but papers on remote viewing and other ESP. Only as I looked through quickly, I saw nothing real, just math, models, and a very large number of words.

    Maybe it’s misleading to call them experimental and theoretical physics. Maybe it’s real physics and pseudoscientifc fantasies until proven otherwise. Something like that would make me happier than the current system of taking all this seriously.

  6. #6 Clay B
    August 9, 2006

    The title of the book made me think about the connection between free will and the Uncertainty Principle. In a classical world all the electrons in your brain are on foreordained paths. Your thoughts (however those result from the physical activity of your brain) are just the result of deterministic physics. It seems to me that the UP enables me to choose to do action A or action B. Is this a common idea?

  7. #7 Chad Orzel
    August 9, 2006

    Isn’t it possible to say that quantum mechanics shouldn’t have any effect on phenomena beyond a certain size?

    That’s basically the tack taken by Bohr and others in making the original Copenhagen Interpretation– you draw a line between the microscopic and macroscopic worlds and classical physics applies on one side, while quantum physics applies on the other. The problem is, there’s no clear and obvious definition of where to draw that line– as John von Neumann points out, a bigger system still ought to be governed by quantum rules, and measurement should just create a bigger entangled state.

    At some point, you have to account for the fact that we don’t seem to see macroscopic quantum superpositions, and whether you call it “consciousness” or somethign else, the role of the observer has to come in. OF course, this is more an issue of philosophy than physics, so you can usually duck the question, but it’s still interesting to think about.

    The title of the book made me think about the connection between free will and the Uncertainty Principle.

    There’s a little discussion of free will, but not in that context.

  8. #8 John
    August 10, 2006

    I have a post on free will and determinism that dips a bit into related issues. Click my name to read.

  9. #9 somnilista, FCD
    August 11, 2006

    They do a good job of avoiding and denouncing quackery.

    Apologies, I must have read it wrong.

    At some point, you have to account for the fact that we don’t seem to see macroscopic quantum superpositions, and whether you call it “consciousness” or something else, the role of the observer has to come in.

    There is a danger when specialists venture outside their field, and I believe this applies to physicists who would invoke “consciousness”, which is more the turf of neurobiologists and psychologists. “Consciousness” is usually poorly defined. I will quote John Wheeler:

    The process whereby the macroscopic world reacts to a quantum event–the process that makes reality–can, in my view, be accomplished with inanimate matter. Following Niels Bohr, I like to call this process “registration” rather than observation (which too strongly suggests human involvement).

    As you can guess, I am not a fan of Roger Penrose’s book, The Emperor’s New Mind.

  10. #10 Joseph W Smith
    November 21, 2006

    A bunch of theories without a conclusion makes dull reading.

    The universe is hostile to life as I know it. How did this speck called Earth get here? The odds are millions to one against it being here. Why are we the most conscious animal on earth? We’ve got too much consicousness of the universe to say we got here without consciousness. Quantum mechanics gives us unrestricted consciousness.

    The “brains” among us, in order to challenge my idea, build straw men. They never answer my question. Why is consciousness such a bugaboo? Why do we insist on putting ourselves in boxes? Why can’t we say there is such a thing as consiousness without confining it to certain preordained conclusions?

  11. #11 Chris1956
    December 1, 2009

    The Uncertainty Principle is meaningless as soon as you can present a model of the particles concerned which explains the wave character of the particle. All models which regard e.g. the electron as shell rotating with the speed of light “c” or as pair of mass less particles circulating each other with “c” or as rotating electromagnetic wave with internal twist like a Moebius ribbon to ensure that always the negative field component is on the outside imply the Uncertainty Principle – or make it futile.
    With all these models which explain many of the otherwise elementary constants, the presence of the electron is confined inside the diameter Delta X, while its macroscopic impulse is known as as (Delta) p. Locally, however, the interactions of these particles are strictly causal and the results are 100% predictable.

  12. #12 socratus
    December 16, 2009

    What is the material basis of Quantum Consciousness ?

    Knowledge of Consciousness. ( A New Era: XXIc.)
    Will Physics explain Consciousness?
    Our brain works on dualistic basis:
    usually consciousness (logically) and rarely unconsciousness
    ( at first it seems illogically but at last it shows as very wise act)
    In book ‘ The Holographic Universe’ Michael Talbot
    on page 160 explained this situation in such way:
    ‘ Contrary to what everyone knows it is so, it may not be
    the brain that produce consciousness, but rather consciousness
    that creates the appearance of the brain ’
    In our terrestrial world the Information ( some basis of Consciousness)
    can be transfer to you only by Electromagnetic waves.
    Lorentz proved: there aren’t Electromagnetic waves without Electron.
    Therefore I say,
    only Electron can be the Quantum of Information/ Consciousness.
    We don’t have any other theory of Information’s transfers.
    We know the Electron is very important particle in our live.
    It acts in Maxwell’s electrodynamics.
    It acts in the atom.
    But how Electron acts in cell and in Outer space we don’t know.
    We need time to understand this fact.
    And when we understand the Vacuum and Electron
    we will know the Ultimate Nature of Reality, it means we
    will know the material basis of Quantum Consciousness too.
    Now nobody knows what the Vacuum and Electron are.
    ” The problem of the exact description of vacuum, in my opinion,
    is the basic problem now before physics. Really, if you can’t correctly
    describe the vacuum, how it is possible to expect a correct description
    of something more complex? ”
    / Paul Dirac /
    You know, it would be sufficient to really understand the electron.
    / Albert Einstein /
    Tell me what an electron is and I’ll then tell you everything.
    / Somebody /
    “… indeed an understanding of psi phenomena and of
    consciousness must provide the basis of an improved
    understanding of quantum mechanics.”
    /Evan Walker /
    ================== .
    Best wishes
    Israel Sadovnik Socratus
    ================== .

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