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Testing for Human Presence

  1. Jul 25, 2013 #1
    Take for example a human being inside a wooden crate. One can not see, taste, touch, smell or hear the human inside the crate, or whatever it is being tested against. We know roughly the outer dimensions of the crate giving an upper limit to the size of the human being within plus or minus a foot in every dimension. One can also get a rough mass of the object plus or minus a kilogram.

    The question is then how would one go about testing to see if there is in fact a human being inside? What if two crates were presented, both having the same dimensions and masses yet one has a human being and the other has lead, or an ape, in it how would one tell the difference?

    The idea hinges on similar limitations presented with measuring sub-atomic particles, without the minute scale. What kind indirect and direct observations in any form can be made to indicate human presence?
  2. jcsd
  3. Jul 25, 2013 #2


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    hi there
    welcome to PF :)

    Xray, MRI or IR testing are the obvious methods

    are you disallowing those ?

  4. Jul 25, 2013 #3
    Those seem all to obvious now, and completely within my restraints.

    Though, I was aiming for more direct methods. I think that is what i mean. It seems like methods using MRI, IR, or X-ray is seeing the object in question and then the decision on whether or not it is human is then derived from those images through common logic of whoever is doing the test. Rather, I was looking for a method that in and of itself provides the results.
  5. Jul 25, 2013 #4


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    It appears that ALL measurements would be considered indirect by your logic, for we would always be interpreting whatever results we measured and deciding whether or not it is a human being inside.
  6. Jul 25, 2013 #5
    A human EEG would be different enough from that of other living things (and non-living things!) to distinguish. Depends whether you can detect an EEG from a distance, i.e. without electrodes actually on the scalp, and through the box.
  7. Jul 26, 2013 #6


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    Are you up for a linear crate smasher and then analyzing the constituent parts, if any, that fly off in all directions. If no parts then that could mean you might have a fundamental crate. One might then need a larger and more powerful linear crate accelerator to test further theory.
  8. Jul 26, 2013 #7
    I guess you are right, my logic was circular.

    This is more what I had in mind, thank you.
  9. Jul 26, 2013 #8
    If the crates are not air tight you could detect human specific pheromones.

    Expanding on this technique you could then determine if the human in the crate is male or female and how closely related they are to the human in the next crate. If you had a database of known pheromone compositions you could identify them by name.

    This is already done on a regular basis using highly trained dogs as pheromone detectors used to seek out specific humans (usually fugitives) inside crates or anything else they might be trying to hide in.
    Last edited: Jul 26, 2013
  10. Jul 27, 2013 #9


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    People need to breath. C02 concentration is already used to detect people being smuggled in container lorries.

    If you could put the crate on vibration sensors you could look for the vibration caused by their heart beat.

    As a person digests food their centre of mass would most likely move slightly. I guess you could try to accurately locate the centre of mass of the crate and wait to see if it moves with time. Not very practical though.

    Subject the crate to heat, and see which one complains the loudest :-)
  11. Jul 27, 2013 #10


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    There is a very simple solution that you have not precluded. Open the crate.

    Is a human being alive or dead? Does it matter?

    Alternatively, if you swing a pendulum over the crate you will be able to dowse an unscientific result. You will not be proven wrong until the crate is opened. Then you can tell the story about Schroedinger's cat.

    Put the crate up for sale on ebay. If the crate actually contains a human the advert will be rejected.
  12. Jul 29, 2013 #11
    I understand a human gives off about 100 watts of heat, that should be
    enough to detect with a decent IR detector.
  13. Jul 29, 2013 #12


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    What if the human is stone cold dead?
  14. Jul 29, 2013 #13


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    I'm not sure why x-ray and MRI are being discounted, it requires very little subjective interpretation to read their results and see if there is a human present.
  15. Jul 29, 2013 #14
    Can the person open the crate from the inside? If so, all you have to do is wait. Placing pizza and beer around the crate may accelerate the uncrating process.
  16. Jul 29, 2013 #15
    Of all the possible things that might be in the crate, the thing to me that would distinguish that it was a human being would be that he is intelligent... for example, he knows how to count.

    When you prescribe that we can't hear what is inside the crate, do you mean that the crate is acoustically isolated so that knocking on the crate would not be heard on the other side?

    Is the crate fixed so that it can't be rocked from either the inside or the outside?

    I think the confirmation that a human being is in the crate must be from some form of communication... but this will seem to always be in a mode that violates the spirit of the set up - that the crate is isolated in all ways. That is so say, if every suggestion is countered with an update to the set up to include a shield or other restriction, then the problem is very tough. You have to use a mode for which no shield has been found, and for which there may be no shield in theory.

    If it was a human being, he could move his arms apart and together... if you experimented long enough you should be able to detect the gravitational change caused by that moving distribution of mass and discover that he is using the movement to signal you with a sequence of natural numbers in binary, etc. This is the only communication mode I can think of that could not be shielded by current understanding...
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