Observation is Measurement, but Measurement is not necessarily “Observation”

“By final [state], we mean at that moment the probability is desired—that is, when the experiment is “finished.” –Richard P. Feynman, Feynman Lectures, Vol. 3

The challenge of defining measurement is evident in the excerpt from Feynman’s famous Lectures in Physics, quoted above–when is the experiment ‘finished’??. This remark arises in his discussion of when to add amplitudes and when to add probabilities, in order to arrive at the correct probability of a particular quantum process:

“Suppose you only want the amplitude that the electron arrives at x, regardless of whether the photon was counted at [detector 1 or detector 2]. Should you add the amplitudes [for those detections]? No! You must never add amplitudes for different and distinct final states. Once the photon is accepted by one of the photon counters, we can always determine which alternative occurred if we want, without any further disturbance to the system…do not add amplitudes for different final conditions, where by ‘final’ we mean at the moment the probability is desired—that is, when the experiment is ‘finished’. You do add the amplitudes for the different indistinguishable alternatives inside the experiment, before the complete process is finished. At the end of the process, you may say that ‘you don’t want to look at the photon’. That’s your business, but you still do not add the amplitudes. Nature does not know what you are looking at, and she behaves the way she is going to behave whether you bother to take down the data or not.” [Feynman 1965 Vol 3, 3-7; original italics and quotations]

We’ve already observed here in previous posts (e.g., this one) that TI provides the process, missing in the standard quantum theory, that triggers the measurement transition and, in Feynman’s terms, tells us when the experiment is ‘finished.’ As Feynman noted, Nature is going to behave this way whether or not you look at something—and TI is what tells us how she behaves that way! (Yet Feynman was not taking into account absorption, so he could not really pin down what makes the process ‘finished.’ ) That process is the response of absorbers. While there can be no deterministic, mechanistic account of what “causes” the final outcome, the measurement problem is solved by TI to the extent that it succeeds in defining what a “measurement” is, and that definition does not require reference to anything outside the theory itself.

We’ll return to the very interesting question of the apparent mystery of the choice of one outcome out of many eligible ones in later posts regarding free will. For now, we’re going to focus on the history of how the concept of an “external conscious observer” became entangled (pardon the pun) with quantum theory in a dysfunctional way, to the detriment of both the study of consciousness and the study of quantum theory.

John Von Neumann and the “Measurement Transition”

It was the brilliant mathematical physicist John von Neumann who put the awkward, but functional, machinery of quantum theory on a rigorous mathematical footing. Von Neumann observed that there seemed to be two different processes at work in the successful application of the theory: (A) the deterministic evolution of Schrodinger’s famous equation for the wave function, and (B) the mysterious indeterministic evolution that occurred during a measurement. While he provided a useful and seemingly correct mathematical description of this Process B occurring during measurement, he could provide no physical reason for it. And indeed, without including absorber response, there simply is no physical reason for it. Since Von Neumann, and everyone else working in quantum theory (except for a few physicists exploring the “direct action theory of fields,” which is the basis for TI) were unaware of the possibility of absorber response, it was concluded by Von Neumann and the vast majority of physicists that “There is no physical reason for the measurement transition.”

Thus was born the resort to the “consciousness of an external observer.” In this form, consciousness was a mysterious and primitive notion, detached from scientific examination, since it was by definition external to the processes under scientific study. Of course, according to TI, Process B corresponds to a specific process under scientific study, so TI does not need to resort to the “consciousness of an external observer” in this way. However, TI in no way denies consciousness! Under TI, the topic of consciousness and subjective awareness regains its place as a legitimate subject of study without serving as an ineffective placeholder for a missing part of quantum theory.

Why is the appeal to an external conscious ineffective? Because there is no way to say where the required “external consciousness” enters. That is, it smuggles in an ill-defined (and arguably undefinable) dividing line between the “nonconscious” things in the experiment and the “external conscious observer.” In the Schrodinger’s Cat experiment, isn’t the Cat conscious? Why can’t he “collapse the wave function”? Why is he just an internal system and not an “external observer”?

This puzzle is the so-called “Wigner’s Friend” variation on the Cat Paradox. Eugene Wigner, a famous physicist, noted that every observer of the box with the Cat becomes himself entangled with the previous participating systems (atom, Geiger counter, vial of gas, etc). So, if Wigner is the one who opens the box, he must be treated by quantum theory as simply a new part of the entanglement, lacking any reason for “collapsing” anything. Appealing to a friend entering the room and looking at Wigner as the relevant “conscious observer” doesn’t help, because then the friend becomes entangled also; and then the friend’s friend, etc. Without any basis for Process B, the chain of entanglement necessarily continues; there is no principled way to say that a “conscious observer” is external to anything, or even what a “conscious observer” is! Yet, since (apart from TI) there is no way around this, the notion of a “conscious observer” as crucial to accounting for measurement results has hung on like a ragged band-aid that has long since ceased to protect the wound.

So we have the following curious situation: owing to the press of history and the long-intractable problem of explaining measurement (without including absorber response), it is now often considered naïve to expect that measurement can be defined without resort to “consciousness.” The failure to solve the measurement problem has been elevated to the “lesson” that “quantum theory is a theory about the observer,” and/or that “quantum theory tells us that consciousness is necessary to collapse the wave function.” While there is truth in the point that the type of outcome that will occur is dependent on how a quantum system is detected—which is addressed by TI, as we’ll see in later posts–the appeal to an ill-defined notion of “consciousness” fails to serve the function for which it is invoked.

Decoherence Fail

Another very prominent way to dispose of the measurement problem is to say that “decoherence” solves it. This approach assumes the so-called “Many Worlds Interpretation,” in which one denies that Process B ever really occurs. The only thing that is supposed to be going on is Process A, the deterministic evolution of all the quantum systems in the universe, all components of one gigantic universal quantum state. The claim is that if one considers only a part of that gigantic state, for technical reasons which we’ll won’t go into here, its mathematical description will be the same as the one that we get from Process B—that is, it will look as though it has undergone the Process B measurement transition, even though it hasn’t.

The notion of “decoherence” is invoked to try to explain why the system we’re looking at will appear to have undergone Process B. Decoherence is the argument that a quantum system is interacting with a very large number of other, distinguishable systems in its environment, and that we are not interested in those other systems, so we just average over whatever they are doing and look only at the resulting description of our system of interest. When we do that, our system seems to be in the state resulting from Process B (basically a list of outcomes with probabilities attached to them.) Then, we only see one of those  outcomes because we are in a particular “branch” of the Many Worlds, the other outcomes occurring in other branches. (Of course, that begs numerous other intractable questions about what it means to be “Me in this branch” as opposed to  “Me in a different branch.”)

If we ignore the troubling questions about which “Me” I am, this sounds like a way to get around the measurement problem. However,  it doesn’t really work. For one thing, the mathematical description of the part of the universe we’re looking at (say our Geiger counter in the Schrodinger Cat experiment) is not exactly a match for the Process B transition—it’s close, but it’s really not the same. (In technical terms, the matrix describing the system has off-diagonal elements, even if they are very small. They need to be strictly zero in order to pass as a real measurement transition.) Another, deeper reason why it doesn’t work is given in an earlier blog post . Put briefly, the whole program is circular: it depends on assuming that the kinds of objects required to be distinguishable, in order to effect the appropriate decoherence, must have been distinguishable from the beginning–before there were any ‘conscious human observers’ around. If the universe was one giant quantum state (with any and all possible quantum entanglement), where did this distinguishability come from? It has to be put in by hand, in a circular and ad hoc way, seemingly based only on our otherwise unexplained experiences as observers.

Thus, standard quantum theory always ends up getting stuck on an ill-defined, primitive appeal to a “conscious observer,” outside whatever it is the theory  is describing.   In contrast, including absorption in the theory allows us to quantitatively explain the conditions for the measurement transition of Process B (even if it is inherently indeterministic). Then consciousness becomes freed from its misguided use as an ineffective explanatory band-aid, and can be considered instead in the more appropriate context of such topics as the “Hard Problem.”  This is the argument that if we assume that all matter is inherently nonconscious (as in Descartes’ conception of matter as pure physical extension and nothing else), then no process involving that sort of dead matter can ever lead to anything conscious.  That is, every aspect of the behavior of such a system is accounted for without its ever having any consciousness or subjective experience.

From this standpoint, it may very well be that consciousness and the capacity for subjective experience is an essential ground to all that is. TI itself takes no position on that issue, which is a metaphysical one. But there would be no inconsistency with TI in taking the fundamental ontology of the universe as consciousness or mental in nature. In such a picture, there would be no artificial dividing line between non-conscious stuff and conscious stuff; all would be inherently conscious. Then the arising of conscious biological organisms would not involve any sudden discontinuity, but would be a process in which consciousness gradually manifests itself in more and more complex and volitionally capable forms, through self-organization. Again, all of that is speculative and open for debate–not part of TI, although certainly consistent with it.

Returning now to the title of the post: TI provides an account of the “measurement transition” from within the theory, by taking into account the response of absorbers. Thus, all we need for “measurement” is an absorber–and this is well-defined in the relativistic version of TI (see this and either of my books for details). Now, observers like humans have absorbers too (our sense organs)–so of course when we interact with quantum objects, we trigger the measurement transition! This is why we can see, e.g., a single photon from a light source like the Sun. But the fact that we are ‘human observers’ is not what is required for that transition. Being a human being is a sufficient but not necessary condition for the measurement transition. The existence of an absorber, whether a human retinal cell or just a ground state atom,  is the necessary and sufficient condition.

Now, are all absorbers (indeed all quantum systems) inherently conscious? Does a photon really make a “choice” as to whether to go through a polarizer or not, as Heisenberg mused? Do quantum systems have some primitive form of volition? Freeman Dyson certainly thought so: “…mind is already inherent in every electron, and the processes of human consciousness differ only in degree but not in kind from the processes of choice between quantum states which we call “chance” when they are made by electrons.” (from Disturbing the Universe.) So this may be the case; but again, that’s a separate, and now well-defined, issue. Indeed, it can figure in providing a basis for free will (already explored here). But we no longer need to use consciousness as an ineffective band-aid for measurement in quantum theory. The study of consciousness deserves better.

 

36 thoughts on “Observation is Measurement, but Measurement is not necessarily “Observation”

  1. Hi, Ruth. Merry Christmas! I have a question for you, but first I’d like to say, I think consciousness MAY cause collapse–the consciousness of the particles, not mine (in the context of the Hard Problem)–which, as you observed, isn’t really inconsistent with TI. But I digress. My question has to do with decoherence. I don’t believe in Many Worlds, of course, but there’s still something I’ve always wanted to know. (Incidentally, I’ve read your ‘Why Everettians Should Appreciate TI’ piece you wrote with Kramer, and it sort of deals with this question). I’ve never had the faintest idea what Deutsch is talking about with regard to universal quantum computers and never thought it seemed possible even in Many Worlds (but this is probably because I’m missing something). I’ve always had the impression that the universe is supposed to be continuously splitting, either due to propagating effects or instantaneously as a whole. Either way, though, I got the impression that when a split happens, even an ‘unmeasured’ particle in superposition splits into parallel superpositions which are not coherent with each other–meaning each superposition continues in a different world. All possible superpositions of a particle are not interfering with each other, though each individual superposition self-interferes in its own ‘world’. But when Deutsch talks about universal computers it seems to me he means that all the different worlds (all possible superpositions) are overlapping during the intermediate part of the computation, which I didn’t think was possible. And a REALLY confusing account of all this can be found in Michael Crichton’s Timeline–which is a fun novel but I’m thinking not particularly good science! :) Anyway, that’s my question.

    1. Thanks Eric and Merry Christmas to you! If I understand your question correctly, I don’t believe there is ever any ‘splitting’ going on. There are quantum possibilities that have no commitment to any particular set of outcomes (the offer waves), and there are absorber responses that bring about the commitment to a particular set of outcomes. Then one outcome really does happen–that’s the actualized emission/absorption event in a single spacetime, which therefore never needs to ‘split’. In my view Deutsch is stuck on a dysfunctional interpretation, subject to my criticism in the earlier post referenced here (i.e. Why the World Cannot Really Split in Many Worlds Interpretations).

      1. What is perhaps more interesting about Deutsch’s work is constructor theory. I’ve tried and failed (to make it publishable or at least interesting) to write about not so obvious similarities (in my opinion) between constructor theory and constructivism. Constructivism is about mental constructs and (still in a preliminary phase) constructor theory is about physical constructs (possible vs. impossible tasks), thinking about thinking and laws about laws respectively. Both concepts are post-modern, post-rational, and non-empirical. Deutsch’s constructor theory can be (in my opinion, somehow) used to eliminate the interpretation of quantum mechanics he prefers and only by constructivism, i.e. a serious change of perspective and worldview.

  2. Thanks, Ruth. I, of course, have never thought there was splitting; I just never thought what Deutsch said made sense even in the context of Many Worlds. For instance, if the universe is splitting constantly during the double-slit experiment, is the electron on its way to the detectors constantly splitting before we even measure it? (The fact that I ask this question may be related to the fact that I still don’t understand why, in at least some MWI descriptions of Schrodinger’s Cat, one has to wait until the box is opened before one’s world splits; couldn’t the split ramify outward without my looking?) This is why I thought I was missing something about Many Worlds–and that it might be helpful to understand what I was missing even though I think it’s wrong. But I’m sorry if my questions are hopelessly muddled, exposing yet again the fact I am an English major!
    On that note, as you recall I’ve written a novel which some of your ideas helped inspire. I’ve also been working on a series of philosophical essays related to the novel (actually, they’re all written by one of the characters in the novel, making them somewhat fictional). These essays deal particularly with questions of science, spirituality, free will and consciousness. Based on the cluelessness of my physics questions ;), you’d probably think the philosophy would not be worth much, but I think there are actually some good ideas there. I thought you might be interested in seeing an excerpt of it, given that it isn’t actually part of the novel (which wasn’t your cup of tea), and thought I might email a small piece of the collection to you, if you’d like.

    1. Yes, the ‘splitting’ is observer-dependent and ill-defined in that sense—what counts as an ‘observer’? IMHO, MWI is a doomed attempt to ‘save the phenomena’ without consistency or clarity as to what it is that is supposedly doing the saving.

      1. Dear rekastner, what makes the splitting in MWI observer dependent? Does the observer dependent splitting in MWI mean that its not Lorentz invariant?

      2. It’s not a matter of Lorentz invariance, but about defining the basis for splitting. Have you read my
        https://transactionalinterpretation.org/2014/07/16/why-the-world-cannot-really-split-in-the-many-worlds-interpretation/
        This explains how, in order to get a sensible sort of splitting that corresponds to our classical macroscopic experience, we have to put classicality in at the very beginning, in an ad hoc way. In other words, we don’t have any way to show that this is how the universe really evolved from the beginning. It’s wishful thinking to assume that the universe started out in just the right way to make it split in accordance with what we see now.

  3. I think that ill-defined nature is (one of the things) that’s always confused me. For one thing, many MWI supporters claim the theory is observer-independent. But, if so, I was thinking about the cat in the box. It splits (in MWI), alive/dead, and the two cats can then be regarded as two separate ‘worlds’? Then the two different cats each entangle with the interior of the box, which should split into two different box-interiors…so even if the box remains closed, but has two interiors, shouldn’t the exterior of the box split anyway, propagating outward to Wigner’s friend, Wigner, etc.? This kind of comes back to my original question on the universal computer–it’s the box that isn’t opened. I guess what I always wondered, regardless of interpretation, is how the quantum algorithms solve problems involving numbers larger than the sum of atoms in the visible universe. This is probably my ignorance showing–I realize there are MANY possibilities–but are there really THAT many inside the quantum computer alone? I was at a loss regarding how anything could explain this, including Many Worlds (and really, it seemed to me that other interpretations could work as well or better). But this might have been what fueled my bizarre question above (regarding superpositions of superpositions)–the way the terms ‘world’ and ‘universe’ are tossed around, it’s often unclear what is meant by them. And then, isn’t the quantum computer being split from the outside, while the computation is going on within? So if the interior of the computer is in superposition, and the computer as a whole is in superposition, is that where the explosion of possibilities is coming from, because the calculation itself is being carried on in many parallel branches? But if the branches are truly parallel, why should they collaborate to produce the final calculation? Do they recombine at the end, or do the many worlds simply overlap inside the computer? Keep in mind, I don’t actually believe any of this ‘splitting’ talk–I’m just trying to understand what it’s talking about.
    Sorry about my long-windedness, here! :)

    1. The problem with the Everettian approach is that the universal ‘quantum state” is static–it just IS. The universe as a whole is not splitting or doing anything! Whatever ‘splitting’ is going on has to be relative to a particular division of ‘system’ + ‘environment’, in a particular basis (kinds of outcomes that could be observed). That is why Everett originally called it the ‘relative state interpretation.’ I don’t think it’s consistent to think of this as ontologically realist and observer-independent, since splitting always has to be defined relative to a ‘system of interest’. What defines that? In order to avoid the kind of incoherent splitting you describe here, Everettians have to presuppose that the “universal wave function” was initially a separable state with already-distinguished things like atoms having well-defined, separable spacetime locations, that are interacting in a classically distinguishable sort of way–the kind of apparently classical world we seem to live in now (this is the circularity–Everettians have to appeal to our classical experiences in order to ‘explain’ our classical experiences). Against that background, one can then define a quantum ‘system of interest’ such as an unstable atom and take it to be interacting with everything else in its ‘environment’. Then the theory (via ‘decoherence’) will lead to a situation in which the atom’s state will lead to a clearly distinguished set of possibilities: one in which the cat is ‘alive’ and the other ‘dead’–and all the other pieces of equipment have corresponding alternative states. The splitting supposedly occurs during the entangling interaction between the atom and all the other parts of the experiment. But the universe as a whole does not split in any objective sense. So that’s why honest Everettians end up having to admit that it’s the observer that has to determine what should be doing the ‘splitting’–and/or it’s the observer who splits. And nobody really can say what that means.

  4. Thanks, Ruth. I assume you’re talking about Wheeler Dewitt–the quantum state is just stuck–not evolving into anything! Beyond that–I guess you can’t quite figure out what Deutsch is talking about either. ;)
    Oh, by the way–when I mentioned above the work I was doing–an essay collection; I hadn’t seen you were sponsoring a TI essay contest, which might have made my comment kind of awkward. Of course (though I like to think I’m quite professional as a writer), as an English major I am certainly not qualified for THAT contest. Also, the ideas I’m working on have nothing to do with TI (though they aren’t incompatible with it). I do actually deal with the idea of a substratum, but that wouldn’t have to be exclusive to either TI or PTI. Ultimately (I hope) my ideas are poetic, science-inspired philosophy–but probably not Philosophy of Science. I deal a lot with the Hard Problem of Consciousness. For instance, I speculate that the qualia from Philosophy of Mind might be what physical reality IS (though I don’t know–are the actualized particles qualia, or are the quantum possibilities qualia…or would reality be subtler than either of these options on its own?) Ultimately, I lean toward idealism and pan-sentience (which I don’t equate with pantheism), yet I also talk about dualism, comparing it to Bohmian Mechanics–which, if you think about it, is sort of a case of interactive dualism in physics. I even suggest that Cartesian dualism and de Broglie-Bohm might make some sense if they were combined, with a person’s mind existing in the quantum potential. Of course, I don’t actually believe this idea–I just think it’s interesting. I also discuss morality, how it can be related to evolution and vice-versa, but how, ultimately, it is a product of consciousness, and moral relativism comes from the (wrong) idea that the universe can be described without consciousness. And I consider evolution itself as being more of a mental process.
    Well…long-winded again. Sorry. Wouldn’t mind hearing what you think of these ideas, if you have time, but if not–Merry Christmas! ;)

    1. You’re more than welcome to enter the TI contest! I just don’t think I would have time in the foreseeable future to read much else, but of course you’re also welcome to send me anything you think would be of interest. TI contest entries should be sent to ruthekastner@gmail.com

  5. Thanks Alec, sorry you haven’t met with success in publishing your work. I’m not familiar with Constructor theory, but I do think that Deutsch’s unitary-only QM approach fails, and in view of his repeated elementary mistakes on his 2000 paper (see my https://arxiv.org/abs/1011.3078 , footnote 2 for identification of his basic calculational errors) , I can’t justify spending much time on his ideas at this point ;) [The irony of course is that (almost certainly) if I made those sorts of undergraduate physics mistakes in anything I wrote, It would probably be used to thoroughly discredit my work. Yet in his case, it seems to pass beneath the community radar–not even a blip. Such is the comedy of life! I don’t take it personally of course ]

  6. Thanks, Esther. ;) I assume when you said Alec you were talking to me? ;) That’s alright, though–I have trouble with names all the time–and faces, too. And I think I get what you’re talking about, regarding how some work is held to a double standard. My field (that of literature) is a lot like that; I think all of the arts, letters and sciences are. It’s almost impossible to discredit what’s in vogue, and good work that is NOT in vogue is tolerated at best. What’s apparently in vogue in science is unitary evolution, string theory, the blockworld and the idea that consciousness is irrelevant, and you reject all four of these claims (and with regard to consciousness, especially, I don’t see how you can possibly be wrong). Yet you have to dot all your i’s and cross all your t’s…and maybe Deutsch doesn’t have to? Regarding my lack of publishing success–I think it’s something most writers go through early in their lives, and I’m still only 37, so I’ve got time. I just hope I’m not one of those geniuses who becomes wildly successful only after he’s dead! I’d settle for being an affluent mediocrity sometime in the next decade!
    Oh–something else you might find interesting, as it relates to your discussion of the Hard Problem in the post above. I’ve been thinking that self-organization doesn’t explain consciousness, but maybe consciousness explains self-organization. In particular, I’m not sure anything in space-time explains why we don’t experience reality with a number of minds–just because our neurons are cooperating doesn’t explain why “I” exist. I think this problem might be addressed in a substratum–where the consciousness of a single mind might be rather like entanglement and ‘action-at-a-distance’. It isn’t precisely this, of course–I don’t think the EPR Paradox is constantly going on in the brain! But maybe the sense of “I” is something that bypasses space and time.

  7. My apologies to Alec, for answering for him–but you have to admit our names sound alike, and apparently we’re both writers, so…
    By the way, Ruth–I’d thought of addressing you as Naomi, but I don’t know…you just seem more like an Esther to me. ;)

  8. BTW, Ruth–I don’t think I was referring to the Binding Problem, when I was pondering why I don’t have several minds (or maybe I was wondering whether the Binding Problem can’t be addressed without first considering the Hard Problem). I think of the Binding Problem as ‘Why is there a coherent experience?’ and of the Hard Problem as ‘Why is there ANY experience?’ and this is sort of in-between. Or, to put it another way, the Binding Problem is ‘Why is the movie in the theater coherent?’; the Hard Problem is, ‘Why is any movie seen?’ and the question I’m considering here is, ‘Why is there an audience of one?’ because there could conceivably be a unified (or mostly unified) SHARED experience involving many selves, and yet this doesn’t appear to happen. It doesn’t happen in Multiple Personality Disorder, which is a single self changing its representation. The best example of when it MIGHT happen are cases of patients whose left and right hemispheres start trying to override each other–but I doubt it happens even then, and still you would have the question of why each HEMISPHERE might be having a single experience. The problem is, saying that the single self happens due to intense interconnectivity (and because the mind of a single neuron wouldn’t be very interesting) makes sense, but it doesn’t really provide any more of an answer than interconnectivity provides an answer to the Hard Problem. It’s as if ALL of our neurons receive the ‘single I’ information (which really isn’t the same thing as the information in our thoughts, and isn’t something that the brain COMPUTES) at THE SAME TIME. As if the ‘single I’ information is being broadcast into space-time (and to all of our neurons at once) from outside.

  9. Of course, I didn’t mean to rule out the idea that we DON’T have hive-like minds. Yet there is at least an appearance that the mind is both complex and SINGULAR–and even if this should be an illusion, the existence of the illusion is puzzling. I’m starting to think that quantum objects are ‘micro-intelligences’. Then more complex, macroscopic NONLIVING objects are colonies of the ‘micro-intelligences’ but not single intelligences in their own right. This would seem to explain why a billiard ball (or a star or even a thunderstorm) seems to be unconscious without making it impossible to resolve the Hard Problem. As far as consciousness is concerned, the billiard ball DOESN’T EXIST–and by that I mean it isn’t a conscious object, but rather an aggregate of ‘micro-minds’. But then when something becomes alive, it (somehow) becomes a single intelligence again. But it isn’t singular in SPACE-TIME; that would be impossible. So a substratum, I think, makes sense as a ‘place’ for the single intelligence to arise; then that intelligence gets smeared out through space-time in a way that seems to create a paradox: a compound single mind. Of course, one other HUGE mystery here is, what is life? And I sometimes wonder if, because the stars ‘cook’ organic compounds, they might have singular minds, too (however unlikely that may seem). It would certainly make your favorite educational cartoon, “Our Mr. Sun”, a lot more interesting. ;)

    1. Yes, makes sense that a living organism would have a ‘captain of the ship’ that takes responsibility for the whole conglomerate. Again Doug Marman deals with this concept in proposing that a living being is a hierarchy of consciousnesses that have all chosen to collaborate and ‘report to’ the guiding consciousness which is the identity of the organism.

  10. Oh, I MEANT to say: “I didn’t mean to rule out the idea that we HAVE hive-like minds.” Oops! Of course, I would rather think of myself as ‘I’ than as a collective.

  11. Dear Dr Kastner,
    How does the de Broglie-Bohm interpretation try to explain the measurement problem?For example,in the double slit experiment,when a detector is turned on,how can it possibly destroy all the pilot waves that are coming through both slits,so that the photon behave like a particle?Could it have something to do with some signal generated by the detector when it is switched on?How can one be certain that the detector itself,which is an electronic device,is not tampering with the experiment?Of course,TI seems to make much more sense,and looks much more beautiful than du Borglie’s!
    Thank you.
    Lineu.

    1. Thanks Lineu, the deB-B theory proposes that there is already a little corpuscle following a deterministic trajectory (one of many possible ones determined by the pilot wave). Then the measurement result is supposedly explained by the detection of the particle, whose location is in principle unpredictable. The waves not corresponding to the position of the particle are thought of as ’empty waves’. However this has been criticized as not really sufficient to explain the measurement result (https://philpapers.org/rec/WALSTM), and the deB-B theory requires a ‘preferred frame’ so is not relativistically invariant in that sense. There is a time-symmetric version of the deB-B theory by Rod Sutherland, but that implies a block world-so in that case all measurement results just exist in the block. I’ve argued that in this case it’s the block world that is doing the ‘heavy lifting’ in addressing measurement (https://arxiv.org/abs/1607.04196) — there’s nothing dynamical going on as claimed. Also, one must use a preferred frame to designate a ‘final boundary condition’ on the universe, so in my view it’s not really relativistically covariant.

      1. Thanks!
        However,how can we be sure,when we perform the double slit experiment,that some hidden influence,coming from the detector(itself an electronic device)is not tampering with the results?
        Lineu

  12. Well in my view of course the detector is an active participant! All other interpretations overlook or discount this. However, the standard em and quantum theory accounts for all the experimental components in an absorption-independent way, so they would probably say they are not overlooking anything.

  13. Hello again–and Merry Christmas–this time much closer to the day. I thought I might relate another crackpot idea of mine which applies to the discussion of observation/measurement. I’ve been thinking that there is a similarity between quantum experiments (such as the double-slit experiment) and the Libet experiment in neuroscience. Perhaps both are probing the boundary between conscious and ‘subconscious’. If one considers all physical reality to be conscious, why should the quantum world not be considered the ‘subconscious’ of physical reality? Then collapse (or absorption) could be viewed as an electron’s conscious realization of itself…and the W time in the Libet experiment could be viewed as the ‘collapse’ of an unrealized thought. Of course, I believe that we are conscious beings–perhaps what most refer to as ‘subconscious’ would be better described as ‘real but not actual conscious thought’, much as you describe the wavefunction as real but not actual. In this scenario, I think maybe ALL of physical reality is thought–including actualized matter/energy. Experience exists, in part, because existence–stuff–IS experience. In Philosophy of Mind terms, actualized quanta might be qualia–mental objects–and properties of position, momentum, mass, spin, etc. are simply properties that a thought, under certain circumstances, has. After all, EVERY physical property has to pass through the lens of conscious experience (at the very least indirectly, as in the case of instrument readings), in order for us to know about it. So why shouldn’t ‘physical’ properties be considered ‘mental’, too? (I have a very short essay on this subject, if you’d care to see it).
    And in case you’re wondering, I don’t think I’ve eaten any Christmas fruitcake containing psychedelic mushrooms. ;)

    1. Interesting. Overall that’s a consistent line of reasoning–you’ve basically re-invented George Berkeley’s argument for ‘antirealism’, at least concerning the mental nature of reality. Re Libet however, Aaron Schurger has an incisive critique of his experimental ‘findings’ that casts doubt on the whole idea of the RP as a measure of non-conscious (brain-directed) decision-making. So I wouldn’t put too much stock in that. See, eg https://www.newscientist.com/article/dn22144-brain-might-not-stand-in-the-way-of-free-will/

  14. I’m quite aware of Aaron Schurger’s critiques–the Libetus Interruptus Experiment (great name!) and think they seem perfectly plausible. I’m also thinking of the version of the Libet Experiment where subjects are able to veto apparent (EEG detected) ‘decisions’ roughly 1.4 seconds before they would have moved–is it the Mitusaki-Hallett Experiment? (I’m not sure how to spell it and always think Mitsubishi-Halibut). In any case, I don’t take the Libet Experiment seriously when it is used as ‘proof’ that we are functionally unconscious, yet I think it may be possible that it is useful in some way in describing the layering of consciousness–for even the ego exists in layers, and I don’t think the sub-ego is unconscious either. Frankly, I’m surprised how people can argue for consciousness-as-retrospective illusion–how do they explain an unconscious brain debating consciousness? I think there’s NO WAY out of this paradox for them that doesn’t rely on the type of circular logic used in the Everettian decoherence program (which is ironic, because I think Many Worlds needs retrospective consciousness for its ‘I’ problem to make sense).
    Regarding antirealism–if I skew antirealist in any way, I think it’s only in the sense of being ‘non-physical’ (and perhaps I don’t even go that far–I think maybe I’m saying that physicality exists as a special case in a broader, quite real, mental world). In this, my thinking may bear some resemblance to PTI–because most hard-core realists would doubt the reality of your wave-function: something between the idea of the thing and the thing itself, that exists not in space-time. Don’t get me wrong, I think your idea’s marvelous–but a lot of people wouldn’t call it physical!!!
    Merry Christmas yet again!!! :)

    1. What you call ‘hard-core realism” here would simply be a definition that to be real, something must be a spacetime object–which is disputable! :) Actually, I think I’m a hard-core realist about theories that work, like quantum theory. That is, I think they work because they describe reality, whether or not it fits into our classical prejudices! ;)
      Merry Christmas to you too!

  15. I just realized–I probably shouldn’t have said hard-core realist (like realism is a bad thing). I think I may have meant ‘naïve realist’. Actually, I think the terms realist and antirealist may be abused (though not by you). If by antirealist one means, ‘I think that at the most fundamental level there is no reality’–that’s NUTS. I suspect most people who call themselves ‘antirealists’ don’t actually believe this. On the other hand, I always thought the traditional meaning of ‘realist’ IS ‘anything that is real must be a spacetime object’. ‘Realists’ who believe this would probably call you an ‘antirealist’. And if one goes by this ‘thinking inside the box’ definition of realism, I think GRW and the Penrose Interpretation (if Penrose’s can be described as a fully developed interpretation) may be the only TRULY realist interpretations. Personally, I like the term ‘real but not physical’–which I guess depends on what one means by physical. The PTI wavefunction is certainly real, but exactly what IS an existence not parameterized by space or time? Those seem to be the two primary yardsticks for a physical object.

    1. No problem. The technical meaning of ‘antirealism’ is actually pretty tendentious–it just means that nothing exists independently of being perceived. So it doesn’t deny that things exist–just says that what exists is dependent on being perceived by some subject.

  16. Of course, there seems to be a circularity there. If existence of ANY kind is ultimately observer-dependent, where do observers come from?–probably preaching to the choir, here ;)
    I think I’ll email you my essay (sometime) on mental ‘realism?’. It’s just two or three pages–and also contains comic and poetic elements. Ultimately, my comparison of Libet and quantum experiments is not a perfect metaphor–obviously one is a classical experiment and the others are not (though, as you and others have argued, the mind is likely quantum, too). Overall, I like the idea of consciousness being divided into ‘actual’ and ‘less actual’ layers (waking vs. dreaming, analysis vs. intuition, for instance), similar to physical reality being divided into categories of actual and non-actual.
    This reminds me–PTI is causing me to wonder…might it be possible to somehow retreat into one of the ‘real but not actual worlds’, where maybe this past year (and its election) never happened? ;)

    1. OK! I too wish I could also retreat into a different world where this election never happened–but PTI just gives us possible events, not possible worlds. There’s only one actual world and we’re stuck with it up to the present moment. Hopefully things will improve!!

  17. What Eric Hamilton is alluding here is very similar to Carl Jung’s ideas (even if some of his publications might suffer from too much daydreaming). Also, in the chapter I wrote (reluctant and aware that someone more competent should have done that) here http://www.igi-global.com/book/rethinking-machine-ethics-age-ubiquitous/125523 I suggest the “I-Thou” (inspired by the book “I and Thou” by Martin Buber) interpretation that is basically PTI with perhaps some addition of Penrose and a notion that it doesn’t make much sense to wonder what is going on within physical objects that will absolutely never be observed, regardless of how much we might be curious about that.
    http://www.dailymotion.com/playlist/x1cbyd_xSilverPhinx_bbc-dangerous-knowledge/1#video=xdoe8u – “Dangerous Knowledge” about Cantor, Boltzmann, Godel, and Turing
    In my opinion the Many Worlds Interpretation totally unnecessarily insists on Cantor’s actual infinity.

    1. Thanks Aleks, while I haven’t read this material yet, I should hasten to clarify that PTI itself makes no specific claim about ultimate substance being conscious or not, so it wouldn’t really be identified with with Buber in that sense. PTI is just a model that explains where the Born Rule comes from and what defines the measurement transition. It also extends TI to the relativistic level and suggests that spacetime is emergent from actualized transactions. So in that sense it’s a physical model, even though as Eric notes this generalizes the notion of ‘physical’ to include extra-spatiotemporal ontologies. As a realist interpretation, PTI does embrace the idea of understanding what is going on within physical objects regardless of whether they are being observed. That is part of the model. Nobody can observe the emergence of spacetime with their 5 senses, but PTI models how that occurs. The question of observation and consciousness is a separate issue that comes in when one wants to solve the ‘hard problem’. Then one can propose that all substance (including quantum) is fundamentally conscious if one wishes, and that is compatible with PTI, but not part of the model per se.

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