If the universe is expanding, what are we filling up?

[Sayonara]

Originally posted by MrL_JaKiri

You have two eyes.

 

Three dimensional vision is implied by their combined use.

Indeed, the human brain is so efficient at ordering 3 dimensional data that it is possible to shift the assembly parameters with surprising ease.

 

If you wear lenses in some sort of goggle assembly that flip your vision vertically, or allow you to see to the left and right (like your average herbivorous mammal), you will have mindless confusion for a while but after a few days your brain suddenly 'switches' to the new configuration. In the case of the vertical flip, you'd have normal vision. I'm not entirely sure what you'd see with the herbivore model but your brain would make sense of it, allowing navigation in 3D space.

 

There was a new species of deep sea squid found recently that has one large eye and one small one, one points up and the other points down. I'd imagine it uses the small one to detect predator silhouettes above it and the large one to detect prey beneath it. Must be complete freak-o-vision.

[Sayonara]

Originally posted by Clown

what he said

That's a much better explanation of your point, cheers.

 

However I'm still dubious about two things:

 

1 - dropping a dimension in a model that is meant to represent an entity that sits 1 dimension above it in the first place. That's... a bizarre way to construct an analogy. I can see the functional aspect but not relative consistency.

 

2 - the fact that you rely so heavily on how the eye works and discard the fact that the brain does all the actual work. I don't find it difficult to imagine a curved volume. Perhaps I am an anomaly.

[Clown]

Originally posted by Sayonara³

Considering the speed with which you replied, I don't think you considered my last post at all.

 

It wasn't in reply to your post. Don't worry, I'm reading your post.

 

At any one time your retinas 'image' only one 2D slice of an object, CORRECT.

 

However, slices are assembled into models that we can directly manipulate using the magic of thinking. This allows us to perceive dimensions and do things like not trip over our own feet.

 

See my post above. This would only be possible if you want to claim the mind is not dependent on the brain, namely the visual cortex for perception of geometric objects.

 

This is how we are able to perceive the shape of the universe.

 

Really? Can you draw a picture of what you imagine?

 

Either way you still haven't proven whatever your point was.

 

Actually, I have shown that the human brain can only view volume through one area at a time. It follows then that if memory and imagination are based on our visual experience, we cannot possibly imagine what a curved volume looks like.

[Clown]

Originally posted by MrL_JaKiri

 

You have two eyes.

 

Three dimensional vision is implied by their combined use.

 

Then why can you still only see one object at any given x,y position at one time?

[JaKiri]

Originally posted by Clown

 

Really? Then why can you still only see one object at any given x,y position at one time?

 

I said implied; from perspective, you know?

[Sayonara]

Originally posted by Clown

It wasn't in reply to your post. Don't worry, I'm reading your post.

I wouldn't bother, you explained everything I was asking about in your last big one.

See my post above. This would only be possible if you want to claim the mind is not dependent on the brain, namely the visual cortex for perception of geometric objects.

I wasn't aware the two could operate exclusively or independently...?

Really? Can you draw a picture of what you imagine?

Get me a block of perspex and a laser cutter.

Actually, I have shown that the human brain can only view volume through one area at a time. It follows then that if memory and imagination are based on our visual experience, we cannot possibly imagine what a curved volume looks like.

No it doesn't. Firstly because the eyes are the sticky point, where only one area can be observed at any one time, and the brain's ability to produce on-the-fly models is not related to the limitations of the eye's biology. Secondly because although memory and imagination are largely based on visual input, it's not the only input to those processes.

[Sayonara]

Going back to the whole 'not being able to see more than one obect at x,y' thing, I have a better example than the glass spheres.

 

Two objects sharing x,y probably don't have the same z. If the nearest object is transparent, then you see the second object. Using the caveats you laid down in your own argument, this demonstrates 3 dimensional vision.

[Clown]

Originally posted by Sayonara³

That's a much better explanation of your point, cheers.

 

However I'm still dubious about two things:

 

1 - dropping a dimension in a model that is meant to represent an entity that sits 1 dimension above it in the first place. That's... a bizarre way to construct an analogy. I can see the functional aspect but not relative consistency.

 

Yes, the balloon sits in an extra 3rd dimension, making it quite clumsy. But as I said, it's only a crude analogy to show a geometric concept. One result of a closed universe is that traveling in one direction far enough will get you right back to where you started! How on earth can a cosmologist explain this weird concept to someone with no experience in Non-Euclidean geometry? So they use this analogy that shows how a 2D stick person would not find an edge or center in his expanding universe. It's not a perfect analogy, but it does at the very least get across a difficult geometric idea.

 

2 - the fact that you rely so heavily on how the eye works and discard the fact that the brain does all the actual work.

 

The area of the brain processing images seems to maintain the spatial structure of the image striking the retina. That is to say, the retina takes a 2D geometric pattern and converts it into a signal that gets sent to the brain. But the 2D geometric pattern is maintained as the data reaches the visual cortex. In the V1 area, the membranes that process the images also maintain this 2D pattern, all the way to perception. So as far as geometry perception goes, our brain deals in 2 dimensions.

 

I don't find it difficult to imagine a curved volume. Perhaps I am an anomaly.

 

Hmmm, come to think of it, curved is sometimes misleading. I think (I'm not sure though) it's just a bad translation for the German word meaning Non-Euclidean. Someone will have to clarify on that one. Why such geometry is difficult, we can still use lower dimension analogies to get basic ideas across. So long as you don't take them so literally.

[Sayonara]

Originally posted by Clown

Hmmm, come to think of it, curved is sometimes misleading. I think (I'm not sure though) it's just a bad translation for the German word meaning Non-Euclidean. Someone will have to clarify on that one. Why such geometry is difficult, we can still use lower dimension analogies to get basic ideas across. So long as you don't take them so literally.

I am assuming by 'curved' that you mean distorted in a dimension that is not x,y or z.

[Clown]

Deleted.

[Clown]

Originally posted by Sayonara³

Going back to the whole 'not being able to see more than one obect at x,y' thing, I have a better example than the glass spheres.

 

Two objects sharing x,y probably don't have the same z. If the nearest object is transparent, then you see the second object. Using the caveats you laid down in your own argument, this demonstrates 3 dimensional vision.

 

If an object is transparent, you can't see it. As far as the eye is concerned, the object doesn't even exist. So you are still only seeing things along a 2D axis.

[Clown]

Originally posted by Sayonara³

I am assuming by 'curved' that you mean distorted in a dimension that is not x,y or z.

 

That definition would work for extrinsic curvature, though not the instrinsic curvature the universe is thought to posses.

[Sayonara]

Originally posted by Clown

If an object is transparent, you can't see it. As far as the eye is concerned, the object doesn't even exist. So you are still only seeing things along a 2D axis.

This is by far the most immediately and obviously incorrect thing you've said.

 

By your logic I can't see a wine bottle (regardless of how much wine I've actually drunk), and I am always walking into glass doors because I don't know they exist.

[Sayonara]

Originally posted by Clown

That definition would work for extrinsic curvature, though not the instrinsic curvature the universe is thought to posses.

I fail to see that there can be a functional distinction when you are working a level above three dimensions.

 

How would you describe the difference between the two types of curvature?

[blike]

Originally posted by Sayonara³

This is by far the most immediately and obviously incorrect thing you've said.

 

By your logic I can't see a wine bottle (regardless of how much wine I've actually drunk), and I am always walking into glass doors because I don't know they exist.

 

Because they are not truly transparent.

 

/doesn't know the argument, just wanted to chirp in

[Sayonara]

Originally posted by blike

Because they are not truly transparent.

 

/doesn't know the argument, just wanted to chirp in

There's no such thing as a truly transparent object. It would have to be colourless, non-reflective, non-refractive and not impede or distort photon paths in any way. It would be utterly invisible but still a coherent entity. If anybody says "like a gas" they will get a slap because (a) gas is made of atoms or molecules capable of interacting with light, and (b) that means the argument that I can see through a window falls down if the window is made of gas, which is a f***ing ludicrous way to reason that Clown is right on this.

 

Even if such an object did exist, Clown's argument would only stand if that object were involved in the situation.

 

Whether or not the object is "truly transparent" (whatever that means) is irrelevant - you only need to be able to perceive the transparent object (window or bottle) and what lies beyond in the same x,y (car outside, milk in the bottle, whatever).

 

However, he is claiming that if I look through a window I don't know it exists, because that's the only way he can not be wrong about being able to see two objects that share x,y.

[Clown]

Originally posted by Sayonara³

This is by far the most immediately and obviously incorrect thing you've said.

 

By your logic I can't see a wine bottle (regardless of how much wine I've actually drunk), and I am always walking into glass doors because I don't know they exist.

 

Nonsense. As someone already pointed out, a wine bottle is not completely transparent. You're going to get reflected light that gives the object visibility. The same applies to water and other almost transparent objects.

 

A perfect example of something that actually is transparent, is air. As far as our eyes are concered, the air isn't there.

[Clown]

Originally posted by Sayonara³

I fail to see that there can be a functional distinction when you are working a level above three dimensions.

 

How would you describe the difference between the two types of curvature?

 

It's a little complicated, but in any case, being able to *see* such curvature would require 4 dimensions.

 

Some non technical info on curvature: http://www.friesian.com/curved-1.htm

[Sayonara]

Originally posted by Clown

Nonsense. As someone already pointed out, a wine bottle is not completely transparent. You're going to get reflected light that gives the object visibility. The same applies to water and other almost transparent objects.

 

A perfect example of something that actually is transparent, is air. As far as our eyes are concered, the air isn't there.

See my post immediately above this one ^.

[Clown]

What about it? I didn't see anything that refutes my claim in it, so here's another look:

 

There's no such thing as a truly transparent object. It would have to be colourless, non-reflective, non-refractive and not impede or distort photon paths in any way. It would be utterly invisible but still a coherent entity.

 

As far as the eye is concerned, a perfectly transparent object is invisible. It's as simple as that. Air typically cannot be seen at all, and that's why we can see through it. It has nothing to do with whether or not the atoms in the air could cause the transparency to be lost.

 

If anybody says "like a gas" they will get a slap because (a) gas is made of atoms or molecules capable of interacting with light, and (b) that means the argument that I can see through a window falls down if the window is made of gas, which is a f***ing ludicrous way to reason that Clown is right on this.

 

If you learned something about how light works, you wouldn't find it so ludicrous.

 

Even if such an object did exist, Clown's argument would only stand if that object were involved in the situation.

 

Come again?

 

Whether or not the object is "truly transparent" (whatever that means) is irrelevant - you only need to be able to perceive the transparent object (window or bottle) and what lies beyond in the same x,y (car outside, milk in the bottle, whatever).

 

Nope, sorry. You can only see the actual glass when certain regions relfect light. Dirty windows are a good example, and in actual locations where you can actually see the glass itself (actually smudges or reflections), you cannot see what lies behind. Try it out for yourself. Fortunately for us, windows do reflect a lot of light, and are clearly visible. Otherwise, they would just appear to be holes in the walls of houses.

[Sayonara]

Originally posted by Clown

stuff

So you're saying you can only see through a perfectly transparent surface such as air, and you can only see through a window or a bottle if... you can't see it.

 

Your original proposition was that one cannot see two objects that share x,y. My counter-proposal was that this is what you are doing when you look through an object such as a window or a bottle.

Your claim that this is not possible is ridiculous. Your digression into the perception of air is irrelevant.

 

This is what I meant when I said that the argument was ludicrous, because the argument I refered to went like this:

 

"I can see an object through a window"

"No you can't because the window isn't perfectly transparent"

"It doesn't need to be, and very few things are, not even gas"

"But gas is close to it therefore I am right"

 

You have to agree that's not the best piece of reasoning ever, and because I was simply proposing that it was a bad argument and did not claim you subscribed to it you can't really grumble that it's there.

You also have to agree that my opinion on that argument has nothing to do with how light 'works', and everything to do with the reasoning process.

 

Your argument now seems to be that light from the distant object and light from the window cannot hit your retina at the same time. This is clearly not true. You are also failing to account for the possibility of looking through a precise and clean glass surface that is coloured, such as green or brown glass. Perhaps you will be able to prove that the light passing through such coloured glass from a distant object doesn't carry any information from the glass when it hits your retina.

[JaKiri]

Originally posted by Sayonara³

There's no such thing as a truly transparent object.

 

Dark matter.

[Sayonara]

Originally posted by MrL_JaKiri

Dark matter.

"For the purposes of this model".

 

Dark matter windows MrL?

[Clown]

Originally posted by Sayonara³

So you're saying you can only see through a perfectly transparent surface such as air, and you can only see through a window or a bottle if... you can't see it.

 

Yes, that is a good definition for transparent objects.

 

Your original proposition was that one cannot see two objects that share x,y. My counter-proposal was that this is what you are doing when you look through an object such as a window or a bottle.

Your claim that this is not possible is ridiculous. Your digression into the perception of air is irrelevant.

 

Not quite, because you don't actually *see* the transparent object you are looking through! So again, you're only seeing one object along the axis at a single time. The key point is that we can't see invisible objects, by definition.

 

"I can see an object through a window"

"No you can't because the window isn't perfectly transparent"

"It doesn't need to be, and very few things are, not even gas"

"But gas is close to it therefore I am right"

 

Once again, if you can see through an object, you are not actually *seeing* the object at all. I don't know why you're making this out to be complicated when it's quite simple.

 

You have to agree that's not the best piece of reasoning ever, and because I was simply proposing that it was a bad argument and did not claim you subscribed to it you can't really grumble that it's there.

You also have to agree that my opinion on that argument has nothing to do with how light 'works', and everything to do with the reasoning process.

 

No, I think you need to read more carefully, because you're attacking a strawman here.

 

Your argument now seems to be that light from the distant object and light from the window cannot hit your retina at the same time. This is clearly not true.

 

Not quite. If the window is invisible, then by definition you cannot see it.

 

You are also failing to account for the possibility of looking through a precise and clean glass surface that is coloured, such as green or brown glass.

 

No problem there. In such a case, you're looking at the reflected image from the glass as opposed to the actual object behind it.

[Sayonara]

Originally posted by Clown

Last post

This has gone on for long enough.

 

I'm not going to get bogged down any further in the semantics of transparency when it's clear that you will change your working definition to suit your current argument.

 

I can look through a window and see something outside. This is a fact.

Reflected, refracted and unimpeded light from both the window and the objects that I can see beyond it will hit my retina. This is a fact.

Ergo, I see them both at the same time.

There is no reason why they cannot share x,y.

 

Your argument hinges on the fact that if the nearer object is truly transparent then light coming from it can either be reflected off its surface, or unimpeded light from the distant object that has passed straight through the transparent nearer object, therefore one cannot see both objects.

 

This is clearly untrue. One cannot see two photons passing through the same x,y in the nearer z at the same time, true, but doing so is not equivalent to perceiving objects. If the retina considered light passing through a green sheet of glass to be reflected light from that surface, explain why there is conservation of depth perception instead of the distant object appearing as a 2D planar image on the surface of the green glass. You can argue light physics all you like, but did it occur that maybe human perception does not operate on a per-photon-positional basis?

 

If I am looking at an elephant, and there is a mouse in the way, I see the mouse and the elephant. I don't consider either to be invisible or non-existant just because there is a proportionally insignificant area of elephant obscured.

 

There's no point making an inprecise proposal then arguing semantics for a few hours to prove it's true. Stop trolling.