Immeadiacy of sensory experience

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Discussion Overview

The discussion explores the nature of sensory experience in relation to the speed of light and the concept of simultaneity. Participants question whether everyday sensory experiences, such as seeing a picture across the room, are immediate or represent a delayed perception due to the time it takes for light to travel and for the brain to process the image. The conversation touches on both scientific and philosophical implications of perception.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that when observing distant stars, we see them as they were in the past due to the finite speed of light, questioning if this applies to everyday experiences as well.
  • Others argue that while there is a small delay in sensory processing, it is negligible for everyday experiences, suggesting that we perceive things in near real-time.
  • A participant raises the idea that there are multiple delays involved in sensory experience, including light transmission and brain processing time.
  • Some participants assert that the notion of "now" is observer-dependent and can vary based on the observer's state of motion.
  • There is a contention regarding whether the delays in perception are significant in thought experiments related to the relativity of simultaneity.
  • Some participants express uncertainty about the philosophical implications of these delays and whether they should be considered within the realm of physics or philosophy.
  • Others mention that thought experiments often idealize conditions and may not account for these delays unless they significantly affect the outcomes.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether the delays in sensory experience are meaningful or significant in the context of physics and philosophy. Multiple competing views remain regarding the implications of these delays on our understanding of perception.

Contextual Notes

Participants note that the discussion involves complex interactions between physical processes and subjective experiences, which may not be fully addressed by physics alone. The relationship between light transmission, brain processing, and sensory experience remains nuanced and unresolved.

dingansich
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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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dingansich said:
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?
Yes.
dingansich said:
Would a phycisist tell me that I would be having an immeadiate experience of the picture frame as it actually "is" as opposed to "was, or vice versa?"
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.
 


dingansich said:
Hi.. Hopefully I have found the correct forum for this inquiry. 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.
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 philosophy, so I've moved it.
 


DaveC426913 said:
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.

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?
 


Evo said:
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 philosophy, so I've moved it.

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.
 


dingansich said:
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 oblect and the ultimate 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?
 


Evo said:
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?

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?
 


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.
 


dingansich said:
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?

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.
 
  • #10


dingansich said:
This chain of events and processes that you lump together take place both in the mind and the external world right?

Sure but it's still not philosophy. It's bio-physiology. The signals are electrochemical in nature.
 
  • #11


epenguin said:
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.

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?
 
  • #12


pervect said:
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.

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


dingansich said:
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?
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 philosophy forum.
 
  • #14


dingansich said:
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?
Thought experiments are idealized. Observers are points, distances are optimal. If it has no effect on the experiment, it is inconsequential.
 
  • #15


DaveC426913 said:
Sure but it's still not philosophy. It's bio-physiology. The signals are electrochemical in nature.

Thank you for the suggested avenue of pursuit.. I will spend some time in the literature tonight!
 
  • #16


DaveC426913 said:
Thought experiments are idealized. Observers are points, distances are optimal. If it has no effect on the experiment, it is inconsequential.

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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  • #17


dingansich said:
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?
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.)
 
  • #18


dingansich said:
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?
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.
 
  • #19


dingansich said:
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?

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.
 
  • #20


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 occurred 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.
 
  • #21


Jimmy Snyder said:
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 occurred 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.
Wait. Did you just claim that - if you had an enormous amount of energy - you could travel at the speed of a photon?
Jimmy Snyder said:
None the less, there is no physical law that prevents it.

Yes there is. No object with mass can achieve the speed of light.
 
  • #22


Jimmy Snyder said:
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.

I don't think that last part is correct, Jimmy.
 
  • #23


The speed of light in air is less than the speed of light in vacuum. There is no reason why you cannot travel faster than the speed of light in air. This is the reason behind Cherenkov radiation.
 
  • #24
If you are looking at a picture frame 3 meters away you are seeing it as it was 1/1,000,000 of a second ago.

Actually 1/1,000,000 of a second is the time it takes for the light to get from the picture frame to your eye. The time it takes for your eye to register the light + the time it takes to transmit the image from your eye to your brain + the time it takes for your brain to process the image and make you aware of the picture frame is 5 or 6 orders of magnitude greater then the time it takes for the light to reach you.
 
  • #25


DaveC426913 said:
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.

maybe this is my difficulty... if you can explain or point me in the right direction to learn about this I am all ears. Thanks in advance.
 
  • #26
dingansich said:
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.

Please do not multiple-post your question across the PF forums. Your 3 duplicate threads have been merged into this one.
 
  • #27


Jimmy Snyder said:
The speed of light in air is less than the speed of light in vacuum. There is no reason why you cannot travel faster than the speed of light in air. This is the reason behind Cherenkov radiation.

Actually from another post a while back, it doesn't actually travel slower, but it will seem to have a slower speed in a medium becausethe photon is absorbed and re-emitted by atoms in that medium.
 
  • #28


Jimmy Snyder said:
The speed of light in air is less than the speed of light in vacuum. There is no reason why you cannot travel faster than the speed of light in air. This is the reason behind Cherenkov radiation.
Oh I see what's you're saying.

(Didn't think you'd make that kind of mistake...)
 
  • #29
can someone furnish me with the concept(s) to study about why light from an object travels differently than one from a source like a star, flashlight, or lightning strike?
 
  • #30
dingansich said:
can someone furnish me with the concept(s) to study about why light from an object travels differently than one from a source like a star, flashlight, or lightning strike?

It doesn't. What makes you think it does?
 

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