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Conscious vs. Non-Conscious Observation

  1. Mar 6, 2007 #1
    I'm not a physics major, I'm just very interested in quantum phenomena. I was hoping someone here could help iron out my interpretation of the Delayed Choice Experiment (in particular).

    The double-slit experiment shows us essentially, that the act of observation creates a physical situation. Mainstream opinion, is that the very act of observation itself, regardless if it is by a conscious or non-conscious entity, is sufficient enough for the breakdown of a wave-function.

    The ramifications of this opinion effectively remove any need for the role human consciousness to affect the outcome of the experiment.

    Now, if this is the case, at what point during the experimental process does the non-conscious observercause the wave interference to collapse (if at all)?

    For example, a non-conscious detector observes the path of a moving entity, and then prints out onto paper its "which-way" information. If common opinion is correct, then at the time the detector acquires the "which-way" information, the wave function collapses. So, regardless if a human were to read the information off the paper, the experimental outcome would already have been created, or in other words, the wave would have collapsed.

    If I understand things correctly, the only way we can know non-conscious observation affected the experimental outcome is for us to read the information on the piece of paper. However, in doing so, it would cause the collapse of the wavefunction, even if the non-conscious observer had not. Therefore, we could never know that non-conscious observation is sufficient, because to say otherwise, we would be required to make an observation ourselves.

    Am I missing something?
  2. jcsd
  3. Mar 6, 2007 #2


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    Whether conscious observation is a necessity for wave function collapse is an interesting question but, can never be decided by experiment, so don't spend too much time worrying about it.

    Your astute remarks seem to indicate you think it is not necessary. I agree, for what it's worth. But it doesn't really matter does it ?
  4. Mar 6, 2007 #3


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  5. Mar 6, 2007 #4
    Thanks for the quick replies. "Astute"? Thanks for the compliment. :cool:

    I'm sorry, but I'm going to have to disagree. If we can find a way to show that human consciousness is the sole factor that causes the collapse, we have just proven that consciousness is beyond its neural correlates. The implications? Let's just say, bye-bye materialism.

    I do agree though, it doesn't appear possible to actually determine this...

    I read the link. Not to sound like a jerk, but has this author ever heard of the field of "quantum physics"? The principle of relativity has no bearing in the quantum world. Quantum physics, unlike Newtonian physics, are governed by a completely different set of rules.
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  6. Mar 6, 2007 #5

    Tom Mattson

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    It's all one world though! While it's true that there are circumstances in which relativistic effects are negligible in quantum (and, for that matter, classical) experiments, those involving photons are not among them. Experiments with photons are among those exceptional experiments that are at once manifestly quantum, and manifestly relativistic.

    Not to sound like a jerk, but I think you should read the article again. :cool:
  7. Mar 6, 2007 #6


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    What the.... ?

    Do you know how difficult it is to get a paper published in Science?

    Secondly, who told you that SR and QM don't mix? What did you think Dirac did?

    Thirdly, without proper relativistic corrections to the band structure calculations a number of solids and high angular momentum atomic orbitals (which all used QM), the theoretical description would not match experimental measurements.

    So this myth that QM does not include special relativity needs to go out of fashion very quickly.

  8. Mar 6, 2007 #7
    Learn something new everyday. Thanks for pointing out my mistake - the last thing I want to do is sound like an idiot, albeit a little late for that.

    With my limited understanding of physics, I can accept that classical and quantum rules can coexist.

    This however, creates a problem when we consider non-local quantum phenomena, both spatial and temporal. Both of these would contradict the principles of relativity, right?...
  9. Mar 6, 2007 #8
    According to relativity it is impossible to use non-local effects to send information faster then light. Doesn't this agree with what you have read?
  10. Mar 7, 2007 #9
    I've read a lot, and am not sure what to believe.

    Due to my lack of knowledge of science, and most notably physics, I'm definitely tempted by some of the more...'radical' theories about quantum theory. Even though this is my case, I'm fine with suspending my belief until I reach conclusion(s) that don't contradict my rationality.

    "Instantanously," is a word I read A LOT, in the context of the subject of non-locality. I understand that this does not make necessarily make it so. Looks like I've got more reading to do. :surprised

    What I'm interested right now is the 'observation problem' in the quantum world. I think an answer has implications which might be able to give us a whole new perspective on the subject of consciousness - if it can be shown that a non-conscious measurement is inadequate.

    Classical physics though, to me seems is ill-suited to provide the necessary groundwork to explain everything in the quantum world. To use its rules to explain quantum phenomena is like trying to fit a square peg into a round hole. It's almost the right shape, but not quite. Physics is concerned with explaining physical reality. In terms of consciousness, I believe it may reside in a larger reality, beyond physical reality.
  11. Mar 7, 2007 #10


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    I'm very hesitant to respond to this, but against my better judgement, I will.

    I'm torn between trying to encourage you to continue with your explorations, and trying to also tell you that one cannot learn physics in bits and pieces whereby the overall coherence of the subject matter is lost. You can't understand physics that way.

    There is a big difference between (i) I just want to learn ABOUT physics out of curiosity and interest; versus (ii) I want to APPLY physics into other areas. The former can be accomplished by reading pop-science books, popular magazines, talking to experts, conversing on public forums such as this, etc.. The latter, however, requires an intimate knowledge of physics that goes beyond just a superficial understanding of it. This can only be done via a formal training in physics, and that means understanding the mathematical formulation of physics.

    When people who only do (i) and then tried to do (ii), then absurd things can happen. We have see how postmodernists have made a bastardization of physics that resulted in Alan Sokal playing a collosal hoax on them.

    So keep your interest in trying to understand, even at a superficial level, various aspects of physics. However, don't try to take that beyond the limits of your knowledge, because there's a tendency to over-extend such things into realms that they shouldn't be in.

  12. Mar 7, 2007 #11
    I appreciate your comments, Z.

    I took the liberty to visit your blog, in which I found none-other than your post regarding the "Bastardization of Quantum Mechanics." It (that, and especially the topic regarding why quantum mechanics is hard to understand) brought up some very good points.

    I wholeheartedly agree that these topics have a seductive lure to those who don't wholely understand the foundation in which it is built upon. I, on the otherhand, will strive to stay true to my resolution in suspension of my beliefs until I am able to coherently absorb their foundational underpinnings. As been said, a house built on sand won't stand for long.

    I still have some more thoughts I'd like to discuss regarding the qualitative differences of classical and quantum physics, but as a matter of fact, I've got to get to my Quantum Reality class. :biggrin:
  13. Mar 7, 2007 #12


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    I like that. (and all the others together: .... ooh, noooo, not again :biggrin:)

    But I would like to chime in with Zapperz. Don't try to understand the difficulties and subtleties of the quantum measurement problem and their attempts at solutions, before having learned the formal machinery well enough to understand what's the problem in the first place. And to be able to do so without going nuts, just tell yourself this:
    we don't know why quantum mechanics works, or whether it describes something or not. We only observe that it works well, and hence we continue to use it. This attitude is sometimes called the "shut up and calculate" approach, and is in any case a necessary stage in learning quantum theory. Afterwards, you can change your mind if you want to.
  14. Mar 7, 2007 #13


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    However, by saying that, you are either demoting, neglecting, or trivializing one very important principle in physics - IT WORKS!

    Many people who do not study science or do not understand how it works often overlook this very important aspect. The fact that many parts of QM actually work and are actually USED in an unbelievable number of applications imply that the validity of its description need not be simply a matter of "beliefs". These are FACTS. Your electronics work not because you or I or physicists/engineers "believed" in some principles, but rather we have demonstrated that what we theorized match what we observed. This is a VERY powerful aspect of the validation of a principle. You will see that in many aspects of life, such degree of certainty doesn't come very often.

    The acceptance of QM should not be based on beliefs if you are aware of the plethora of empirical evidence that it has. So maybe, rather than trying to understand the concept of it, you may need to start from the other end, which are the experimental evidence and applications of QM.

  15. Mar 7, 2007 #14
    It's certainly not my intention to discredit the validity of quantum science. I know that some aspects of quantum physics have been among the most tested phenomena in all of science. The statistical behavior, non-ambiguous measurement results, the complimentarity characteristics of particles/matter can not be disputed. However, as I'm sure you all would agree, it's what we infer from these characteristics which causes the, as you would say, the "bastardization of quantum mechanics."

    I think though, if there is any chance of another 'scientific revolution' to take place in our society, quantum theory would be a source, if not the source for this next step in our evolution.

    My field of interest is cognitive psychology/science. I plan on enrolling into grad school at the start of next year. Are there any areas in quantum theory that could be explored, which may pertain to the human mind? For instance, manipulating bosons and fermions to initiate a noticable change in the qualitative aspect of a larger entity such a cell?
  16. Mar 8, 2007 #15


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    As ZapperZ pointed out, what one *infers* (about "why", "how"...) from a working formalism is, strictly speaking not science anymore. Science is about observations, and the relationships between observations. It's a kind of miracle that the relationships between observations can actually be described by a mathematical formalism which is, after all, not so terribly difficult (I mean, it can be grasped by the human mind).
    From the moment we try to give a "meaning" to all that, we leave the strict realm of science. Which doesn't mean that it is something "bad", on the contrary! We, as human beings, are in some kind of need to give meaning to things, in order for us to master them intellectually. So it is, for pedagogical/psychological reasons a good idea to give meaning to the elements that constitute the relationships between observations. It can also be a good source of inspiration. But it is, strictly speaking, not part of the scientific machinery. You cannot use the methods of science to "prove" a certain meaning or not.

    Now, for most of science, this is not a big deal: in most of science, the "elements that constitute the relationships between observations" correspond to rather intuitively clear notions. But in modern physics (relativity and quantum theory), this doesn't work well. The notions seem to clash with our intuition. Hence all the debates.

    I'm no expert, but the human brain seems to be an entirely classical "machine". Certain people (Penrose is the most known), have, at a certain point in time, speculated that the human brain might have elements of a quantum computer, but estimates have been made about what would be possible for that, and the possibilities for this to be true are rather meager. It's kind of fringe speculation.
  17. Dec 1, 2008 #16
    Reality is what we make of it.

    If a tree falls in a forest and no one is around to hear it, does it make a sound?

    I used to guffaw at that question and think, "of course it does..."

    Now, I find myself questioning whether or not the tree actually falls until you're there to observe it falling or already fallen..
    /sigh Quantum Physics...

    So, Double Slit Experiment.. there is no one there to question which slit the particle passed through, until we, the concious observer look at the result.

    Recreate the Experiment on a larger scale that a video camera can watch, feed the video into a tape in another empty observerless room, then take the tape, and mail it across the world. Travel to "Across the world" and pick up the tape, Put it in a player and leave the room after hitting play.
    Come back into the room and turn off the tv and rewind, then turn the tv back on and hit play, and the "wave function" didn't collapse until your eyes actually observed the marble going through the slit halfway across the world.

    Now I wonder..
    If you sent multiple marbles through 1 at a time, with the video camera recording them, but you didn't actually watch the marbles go through, but you put paint on the marbles so that they left a mark.. would you break down the wave function when you look at the wall to see where the marbles hit. My answer would be yes.. and you would see two lines of paint on the wall of course right?
    /sigh.. im going to go take a nap. =]

    seriously though.. only 2 lines right? >.>
  18. Dec 1, 2008 #17


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    Firstly, we don't know what consciousness is quite yet. If by conscious observer you mean human observer, then no that has nothing to do with the double slit experiment.

    When people say observation changes the outcome of the double-slit experiment, they don't mean that you can change the outcome of the experiment by looking at it with your eyes.

    Imagine you go into a dark room with a flashlight. Imagine that the the flashlight has a knob which you can turn to change the wavelength of light it emits. Now if you go into the room and turn on your light, you will see something. If the objects and things happening in the room are quantum, then what you see will change when you change the wavelength on your light. It doesn't matter whether it's a human who went into the room or some non-living thing like a camera. If you send in a robot with a video camera, it will see/record the same thing that you saw.
  19. Dec 2, 2008 #18
    yeah, but does the wave function then collapse as the robot's video camera views it, or when you watch the video?
    and, how do we know?

    (i know this hardly matters, just wondering what the formula's say)
  20. Dec 2, 2008 #19
    "we can be sure the photon does not know what will be at the end of the interferometer when it enters"

    Does this mean that there's no difference between a conscious observer and an unconscious one ? Or what ?
  21. Aug 14, 2011 #20

    I dont understand why not. For the double slit, with no observation (conscious or otherwise) we see an interference pattern. With a conscious/human observation we see no interference pattern. Simply set up an apparatus which 'observes' a slit, but do not look at the result. If you see an interference pattern, the non-conscious apparatus made no 'measurement'. If we dont see an interference pattern, then the non-conscious apparatus did make a 'measurement'. What is wrong with that?
    Last edited: Aug 14, 2011
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