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Immeadiacy of sensory experience

  1. Nov 7, 2011 #1
    Hi.. In astronomy we know that when we observe a distant star that we are seeing it the way it looked a long time ago, how long is dependent on the speed of light and the distance between us and that star. It might not even be in existence anymore. Does physics apply the same logic to our "everyday sensory experience? As I sit here looking across the room at a picture in a frame, even though the distance is small, am I seeing it as it was in the very near past? would a phycisist tell me that is an immeadiate experience of the picture frame as it actually "is", as opposed to "was?"

    thanks.. ding.
     
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  3. Nov 7, 2011 #2

    DaveC426913

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    Re: immediacy of experience..

    Yes.
    No. Since the speed limit of the universe is c, and nothing can reach you faster than that, a physicist will tell you it's meaningless to talk about this "is" as if it were accessible. It isn't.
     
  4. Nov 7, 2011 #3

    Evo

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    Re: immeadiacy of sensory experience

    There is always a very small delay in our brain processing an image, but it's so minute that when you see something it's virtually in real time.

    And this isn't philosphy, so I've moved it.
     
  5. Nov 7, 2011 #4
    Re: immediacy of experience..

    Thanks for the response Dave. So the would he/she tell me it is meaningless to talk about the star as it "is" currently also?
     
  6. Nov 7, 2011 #5
    Re: immeadiacy of sensory experience

    Sorry about the post but I am new and not sure of correct category. Quick question though because I believe it is philosophical. Am I correct in thinking that not only is there a delay in respect to internal processing but also a second delay in respect to transmission of light?

    light emitted from object > distance and time traveled to eyes > processing time > sensory experience.. it seems to be at least 2 durations of time in between emmitting of light by object and the ultimate experience.
     
  7. Nov 7, 2011 #6

    Evo

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    Re: immeadiacy of sensory experience

    Yes, the image has to hit first. That's part of the negligible delay at such a short distance.

    It's science, it can be measured, what's philosophical?
     
  8. Nov 7, 2011 #7
    Re: immeadiacy of sensory experience

    Isn't there some kind of discourse related to this somewhere in the philosophy of perception or some similar field of thought in philosophy? This chain of events and processes that you lump together take place both in the mind and the external world right?
     
  9. Nov 7, 2011 #8

    epenguin

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    Re: immediacy of experience..

    The processes you sweep under the carpet with the word "see" take and last vastly longer than the time the light takes to cross the room so the physicist as such has not much to tell you about them.
     
  10. Nov 7, 2011 #9

    pervect

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    Re: immediacy of experience..

    The physicist would most probably tell you that the notion of simultaneity, the set of points in space-time which are defines as being "now" depends on the observer - in particular on his state of motion.

    At least this one would. Others might give you different answers.
     
  11. Nov 7, 2011 #10

    DaveC426913

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    Re: immeadiacy of sensory experience

    Sure but it's still not philosophy. It's bio-physiology. The signals are electrochemical in nature.
     
  12. Nov 7, 2011 #11
    Re: immediacy of experience..

    It is odd you say that because a large portion of the thought experiments dedicated to the relativity of simultaneity incorporate "SEEING". I just have never heard any physicist account for that small amount of time dedicated to transmission of light in those thought experiments. Granted it is inconsequential to the types of motion we experience daily but when a phycisit deals with objects moving at near light velocities it could become a problem if not accounted for right?
     
  13. Nov 7, 2011 #12
    Re: immediacy of experience..

    Thanks for the time pervect.. as you were typing I was bringing that notion of RoS up in the following post :)
     
  14. Nov 7, 2011 #13

    Evo

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    Re: immeadiacy of sensory experience

    If you want to research the philosophical wanderings, you can do so, but in order to post in philosophy, you will need to follow the guidelines in both sets of rules stickied at the top of the philosphy forum.
     
  15. Nov 7, 2011 #14

    DaveC426913

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    Re: immediacy of experience..

    Thought experiments are idealized. Observers are points, distances are optimal. If it has no effect on the experiment, it is inconsequential.
     
  16. Nov 7, 2011 #15
    Re: immeadiacy of sensory experience

    Thank you for the suggested avenue of pursuit.. I will spend some time in the literature tonight!
     
  17. Nov 7, 2011 #16
    Re: immediacy of experience..

    Really? http://books.google.com/books?id=gQ...i=tondSZLWOpnGywTa_pHyDg#v=onepage&q&f=false"

    In Einstein's thought experiment Speed of Light(SoL) is accounted for in the case of the experience of lightning but the Sol in respect to the rays of light emitted from the surface of the train are not mentioned. Why is that?
     
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  18. Nov 7, 2011 #17

    DrGreg

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    Re: immediacy of experience..

    The language that is used to describe thought experiments can sometimes be ambiguous. When people talk about what an observer "observes", or an observer's "point of view", they often don't mean what the observer would see with their eyes. It is assumed that the observer makes a calculation to account for the time delay for signals to travel; or instead you can imagine that when an event occurs there is a little clock next to it, synchronised to the observer's clock, so that the observer can read the clock and allow for the time delay.

    (The complication in relativity is that different observers disagree about how to synchronise clocks.)
     
  19. Nov 7, 2011 #18

    DaveC426913

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    Re: immediacy of experience..

    Because, in one case, it is relevant, in the other it is not.

    If you are not grasping why the rays of light emitted from the surface of the train are not relevant to the experiment, I'm afraid we're going to have a lot of trouble helping you further.
     
  20. Nov 7, 2011 #19

    epenguin

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    Re: immediacy of experience..

    When you read physicists talk of "seeing" do not take it literally, no more than if you read them saying an electron or something "feels" a force. Well I think they will confirm this.

    As Bertrand Russell observes in "The ABC of Relativity" the "observers" they talk of do not need to be human, who have their limitations when it comes to timing flashes emitted by another observer or themselves. The job can be done by suitable instruments and recorders, you can pick up the results afterwards.

    Humans are IMHO an unwelcome distraction when relativity stuff is hard enough to understand anyway and I wonder if I am the only one who hates Alice, Bob and Charles and the silly signals they send each other?

    BTW when I said you swept "see" under the carpet I did not mean you could do otherwise because no one can. "Seeing" is scarcely understood neurophysiology, quite different from well understood physics.
     
  21. Nov 7, 2011 #20
    Re: immeadiacy of sensory experience

    The speed of light is finite and so under reasonable conditions, there will be a delay from the time that a photon leaves the picture frame until the time that it reaches your eye. However, the speed of light in air is slower than the speed of light in a vacuum. Therefore, there is a frame of reference in which there is no time delay. If you were traveling in that frame, your clocks would register the fact that the emission of the photon and it's collision with your eye occured at the same time in that frame. You would need an enormous amount of energy to attain that frame and so it is impractical to attempt this trick. None the less, there is no physical law that prevents it. There would still be a processing delay as your brain turned the photons into a mental image.
     
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