Why can we see space, but not time?

[TheDemx27]

why you think you are seeing a 'distance'? Because (i) you have depth perception because of your two eyes and (ii) the light from the object reaches your eyes AT DIFFERENT TIMES! In other words, your sense of distance actually depends on some time differences!

Are you meaning to say that a person's sense of distance is based on how much time it takes for the light to enter somebody's eye? If so I must say that cannot be true. First of all, light coming reflecting off of objects with varying distances from your eye will being entering your eye at the exact same moment; if the light source is continuous. Secondly, I believe it is near impossible for anyone's brain to recognize such small differences in time.

I'm pretty sure that distance is judged exclusively by depth perception and how the brain interprets the object with reference to its environment. Forgive me if I misunderstood.

 

[bitewhite]

As many of the people in this thread have been getting at, the sensation of space is algorithmic in nature, not an actual sense. Our sensation of space is largely derived from our brain's processing of the raw input of light that picked up by the rods and cones in our eyes which is really no different from the many other conceptualizations of space that exist. For instance, bats achieve a sensation of space an entirely different way by using sound waves which their brains are then able to make sense of. So essentially the question of how and when raw inputs like light and sound translate into a conscious observer experiencing the phenomena of "space" is left up to the philosopher.

 

[lightarrow]

If space and time are really related, why is it that we can see space, but we can't see time?

I can: if I look at my watch, I see the hands moving...
(To "see" here I mean to "perceive").

 

[A.T.]

Richard Feynman on whether we "see objects" or "see light":

http://www.youtube.com/watch?v=EyssfKRsgMU#t=4512

 

[D H]

Actually, you don't see space. You see the object!

Sometimes you don't even see the object if the object is reflecting or emitting light in a strange way.

Example: Plop down in your favorite sofa or chair and plop a movie in your home entertainment center. Your eyes see light; the source is irrelevant. Your brain interprets the signals from the eyes not as a strangely lit panel but as the movie you wanted to watch.

 

[meBigGuy]

The eyes respond to light, the brain processes it and then constructs our sense of objects. We sense patterns of brightness and color. A blind person given sight cannot perceive or recognize a coke bottle until he touches it. It just a pattern of intensity and color, not an object. (read "Breaking Through") And, the higher level neurological processes that process the light/dark/color patterns can easily be confounded. (all starting with the eye's frequency sensitive sensors)

We perceive both space and time, but they are very different experiences. We perceive the 3 spatial dimensions much differently than we perceive the passage of time.

 

[mfb]

A blind person given sight cannot perceive or recognize a coke bottle until he touches it.

That is just a matter of training. That person needs training just as a newborn baby needs (but it is easier for the newborn).

 

[bahamagreen]

1] "Seeing" ultimately occurs in the occipital lobes at the back of the brain, and all the brain has to work with is nerve cells, action potentials of nerve cells exciting or inhibiting subsequent nerve cells... the brain does not "see" physical objects, nor the light from objects, it has only the signals from upstream nervous activity with which to abstract the experience of seeing.

2] Detection of edges, angles, shapes, lateral movements, rotations, and many other features are extracted within the ten layers of the retina before the signals leave out the optic nerve.
The surface of the cortex of the brain also has ten functional processing layers, and the retina is very much a specialized projection of the brain's cortical surface through the optic nerve to the back of the eyeball.

3] A pair of lateral geniculate nuclei take signals from each half of each retina and form six layers from the two eyes - six layers of processing structures. This is where much of the processing of depth is done by comparing and processing the different signals in adjacent layers from the two eyes.

4] Very many more things are going on... there is a very complicated system that allows you to shift your eyes from looking at one object to another without causing a mass movement of the background across the field of vision - so you can move around and move your eyes around and still percieve a "steady" field of view...
But ultimately we only perceive our own nervous system from the inside out; we don't actually see objects or light, we don't hear sounds, etc. We abstract our entire perception of the world... space, distance, size, color, perspective, time, motion, and all conceptual relations of these.

5] Just to be clear; when you watch a tennis match and think you are "seeing" the moving yellow ball, the part of the brain that process the identification of the shape as a ball, the part that processes the color yellow, and the part that processes the motion of the object... all three of those features are processed in physically separate and different structures. Yet, these are integrated by further processing and you "see" a moving yellow ball as a single whole object of perception - so the level and degree of feature detection, abstraction, and integration is very subtle and sophisticated. Virtually nothing is known about how it really works even today.

 

[D H]

Just to be clear; when you watch a tennis match and think you are "seeing" the moving yellow ball ...

And this happens even when one watches the tennis match on a TV screen, where there obviously is no moving yellow ball.

 

[jacassidy2]

ModusPwnd and A.T. - Your comments raise a basic fact I'd like to explore. I see the light energy or feel the heat energy from a star or a lighted earthbound globe in my room as if it only traveled from the object to my eye or skin, which is not true. I don't see the wave energy in a plane perpendicular to my position, unless there is some dust in the air that reflects the waves, in the case of light, or some appropriate sensor in the position I want to measure. How come? Why can't I see the wave from the side? I say here it's because even a light wave is somehow (don't know how) like a mechnical wave like sound or waves in the ocean. The wave is not seen in the energy that produced it, but in the disturbance in the medium through which it passes. WOW

 

[Drakkith]

I don't see the wave energy in a plane perpendicular to my position, unless there is some dust in the air that reflects the waves, in the case of light, or some appropriate sensor in the position I want to measure. How come? Why can't I see the wave from the side? I say here it's because even a light wave is somehow (don't know how) like a mechnical wave like sound or waves in the ocean. The wave is not seen in the energy that produced it, but in the disturbance in the medium through which it passes. WOW

You can't see the wave from the side because the wave itself must enter your eye in order for it to interact with your retina and allow you to see.

 

[jacassidy2]

You can't see the wave from the side because the wave itself must enter your eye in order for it to interact with your retina and allow you to see

Yes and do you find that interesting and worthy of investigation? Are waves vectors? How many dimensions are involved and how does that affect human perception? And you made no comment on the difference between mechnical and electromagnetic waves. ANy thoughts there?

 

[Drakkith]

Yes and do you find that interesting and worthy of investigation?

I might have if I had lived in the 1800's when this stuff was first being figured out.

Are waves vectors?

Yes, EM waves are oscillations of the electric and magnetic field vectors.

How many dimensions are involved and how does that affect human perception?

I don't really understand this question. There are 3 spatial dimensions. Their "effect" on human perception is that our perceptions are the result of us living in a 3d universe and not another one.

And you made no comment on the difference between mechnical and electromagnetic waves. ANy thoughts there?

The difference is that mechanical waves involve particles pushing up against each other in some way while EM waves are oscillations in the EM field.

 

[Dale]

Why can't I see the wave from the side?

Why does this surprise you at all? Are you similarly surprised that you cannot taste food that is not in your mouth or sounds that do not arrive at your ears? Are you surprised that you cannot feel the texture of an object that you are not touching? If you understand that all of your other senses require the thing sensed to interact with your body then why would you be surprised that vision is the same?

The fact that you are at all surprised by this seems very strange to me. IMO, what you are suggesting would be FAR more surprising. I really don't understand your reasoning here.