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The smallest measurement device

  1. Apr 25, 2009 #1
    What is a smallest system which can be considered a 'measurement device' in terms of CI. How many atoms does it consist of?
  2. jcsd
  3. Apr 25, 2009 #2
    What is the definition of the so-called "measurement device"?
  4. Apr 26, 2009 #3
    I want to ask CI-er about it :)
  5. Apr 26, 2009 #4
    Looks like there are no people left who believe in CI :)
  6. Apr 27, 2009 #5


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    To avoid confusion, I don't declare myself as CI.
    But I think I'm reasonably close to CI, atl east relative to Dmitry to add my comments fwiw.

    The question has some complications, but I'll give a simple answers and add that the
    real answers can only be made in a evolutionary context.

    I take "measurement device" to be synonmous to "observer" here. This means you ask, what the smallest possible observer is?

    The first thing I'd note is that this question is always raised by a second observer. In this case Dmitry, who happens to be human. But in that case, there is only one first hand observer, and that's Dmitry. So when his observer reads the "measurement device", he is in fact observing another observer, which is nothing but a part of the first observer environment.

    The question becomes, what is the smallest part of the enviroment with some varying degree of coherence, that the first observer can _distinguish_?

    In this case, we can fapp replace Dmitry with any human. So in my opinnion the question Dmitry raises here, is the same as ask, what are the smallest possible constitutient in the universe? Certainly, it's not counted in atoms, it would be on subatomic level.

    Of course, these "observers" are can not described as "classical". This may be a problem for the strict old school CI. But this is why I do not declare myself as CI. To me, classical observer, or classical measurement apparatous are only an idealisation, that is emergent within the view of another observer during special occasions. My view does not rely on "classical" observers.

    So, the notion of the "set of all observers" is in my view, not objective. Because each observer, has their own inside view of other observers. And for those who point out that this implies a consistency problem, my response would be that this apparent "consistency problem" is not really so. It can instead be seen to be the cause of interactions beteween the observers. The apparent inconsistency of views, exerts a selective mutual pressure on all observers in the game, that can be interpreted as forces. Pretty much like the idea of gauge theory, but with the difference that there exists no objective gauge symmetry. Instead it's much more self-referencing and self-evolving symmetry idea.

    The key is to go from a realist birds view of symmetries of nature, to an instrinsic frogs view. To make this strange suggestion work, the implication is that all structures are evolving, and it's not evolving globally as per some objective law. It evolves differentially as per subjective(or local, meaning almsot the same thing here) beliefs. The result is both evolving beliefs, and evolving evolution rules.

    The similarly to GR, dynamics in spacetime and dynamics OF spacetime is clear, but I'm picturing taking it yet another step, to apply to generic structures, in an intrisic information view.

  7. Apr 27, 2009 #6


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    I think that they still exist, but that most of them prefer to shut up and calculate. :biggrin:
  8. Apr 27, 2009 #7


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    I suspect a slight clarification might be needed. What I mean with this.

    local vs global, as referring to spatial degrees of freedom, can be seen as a special case of subjective vs objective.

    Now, picture extending relativity to more than just spatial or tempo-spatial views. Then one would expect something even more weird. And also att that the correspondence of Einsteins equation, is instead evolving, thus not fixed. This tangents also some ideas of Ted Jacobsson and others which argue that Einsteins equation is best seen as an "equation of state" rather than as a fundamental law. This is in line with how I see it. Thus, LAW, is to be seen as a sort of equlibrium condition that is constantly beeing re-equilibrated, and without a global, objective equillibrium. (no heath death problem).

  9. Apr 27, 2009 #8
    You can do the electron twin slit experiment, where the slits are the two protons of a hydrogen molecule, by exciting one electron with a photon. This first electron can be measured (or not) according to whether the second electron significantly interacts with the first. So you could argue that a single lepton is enough to count as the measurement device (although a CI adherent would probably prefer to draw the line somewhere else so as to have thermodynamic irreversibility... which they would instead call collapse irreversibility).
  10. Apr 28, 2009 #9
    But if we know what electron was exited then there is no interference, right?
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