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Author Topic: Do we see the world as it really is ?  (Read 9699 times)

Offline neilep

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Do we see the world as it really is ?
« on: 15/06/2004 21:32:12 »
From what I understand, we receive images to our eyes in two dimesnsions, and then they're flipped upside down and the brain has to do all the hard work to sort it out.....Why is our biology so that we receive the pictures in 2D and upside down ?

Your two dimesnional and right way up answers I await with optimistic anticipation...ta



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Offline valley

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Re: Do we see the world as it really is ?
« Reply #1 on: 15/06/2004 23:13:05 »
Well...

We see it in 2D because what we are detecting is the light coming at us. This light does not have a 3D element so we are not discarding information by recieving it in a 2D manner. If you want 3D input then you have to get it by sending out something in a known state and analysing it when it gets back to you, like sonar.

The upside-downness is a bit of a red herring - it doesn't matter which way up it is, it's what we make of it that matters. There were some experiments a while back where someone wore glasses that made the world look upside down. After a (fairly short) while, their brain adjusted. This was quick enough that it certainly wasn't due to their neurons all re-aligning themselves in their brain! Think about it - why do you see up at the top and down at the bottom anyway? It's all just perception.

In my opinion, the really silly bit of the 'design' is the fact that all the wiring is poking out in the wrong direction, between the incoming light and the receptors. This means that the brain has to ignore all that interference, including the blind spot which is where all the neurons join up to go out the back of the eye as the optic nerve. However, even this isn't so much of a problem as your impression of seeing a detailed picture of the world is an illusion, in fact you're seeing a lot less than you think you are. There are some lovely change-blindness experiments (try google) that can demonstrate this by showing that you cannot remember from one moment to the next what you were seeing the moment before. We just rely on the world itself to not change too much in the interim :)
 

Offline neilep

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Re: Do we see the world as it really is ?
« Reply #2 on: 15/06/2004 23:45:37 »
Thanks Valley.....so it's the brain that we really see with then as it does all the jiggery pokery.

With regards to the 2d light thing..... I see, even though the light is bouncing off a 3D object  we still see it as a 2D one and then thanks to good old brain we can see in 3D. And the same with the blind spot thing too !!..

Thanks Brain...

Hey !!.could it be that the same can be said for tactility ?....perhaps we are all two dimensional creatures and thanks to nice friendly brain, we all believe we live in a three dimensional world. I think I can feel the corners and depth of my desk but perhaps it's all some brain illusion eh ?

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Offline tweener

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Re: Do we see the world as it really is ?
« Reply #3 on: 16/06/2004 02:56:32 »
Or maybe we live in a four (or eleven) dimensional world, and our brain is limited to perceving only three plus a sense of time.(?)

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Offline valley

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Re: Do we see the world as it really is ?
« Reply #4 on: 16/06/2004 10:02:46 »
Oops, I forgot to mention that of course the fact we have two eyes means we get two different "2D" inputs so we can construct 3Dness from that...

Tactility is a bit different, I'd argue. As we can gather sensation pretty much all over our body surface, we can sense 3D-ness by using two different body bits to feel two bits of surface at once. Or a million different touch sensors to feel a million tiny bits of surface at once. However, the sense of having a constructed 3D world inside our heads is all down to the brain again. Maybe our inability to remember too much detail about what we have felt (anyone blind out there who could tell me how much?) is a useful way to realise how little of what we imagine we see is actually stored in our minds. And if you feel a scene, do you store the information about it as touch or do you convert it to an image and remember that?
 

Offline neilep

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Re: Do we see the world as it really is ?
« Reply #5 on: 16/06/2004 12:26:24 »
Good points Valley !...what about people with one eye ?....I can still see what I perceive to be a 3D image when I use one eye!..I assume it's good old brain doing it's happy work again....but if I was born with just one eye working I wonder if my 3d perception would be different.

I can believe that it's more difficult to retain 'tactile' knowledge as we are predominately eyesight led creatures....well...I would say that sight is our foremost sense anyway......I'm quite sure I would rather be deaf than blind. Now I wonder how a blind person (from birth) retains the info on the objects they have touched, what kind of images (if any) do they manifest ?

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« Last Edit: 16/06/2004 12:32:17 by neilep »
 

Offline neilep

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Re: Do we see the world as it really is ?
« Reply #6 on: 16/06/2004 12:30:45 »
quote:
Originally posted by tweener

Or maybe we live in a four (or eleven) dimensional world, and our brain is limited to perceving only three plus a sense of time.(?)

----
John - The Eternal Pessimist.



I wish I could step outside my reality and look inside and give you the answer John....assuming that  ' outside ' and ' inside ' are appropriate terms to use.


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Offline valley

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Re: Do we see the world as it really is ?
« Reply #7 on: 16/06/2004 12:37:13 »
If you have only one eye, you can get 3D data simply by moving your head about. This is what animals do if they have their eyes on entirely different sides of their heads (e.g. rabbits); in that case, it's like they have two single eyes rather than a pair and the movement is equivalent to each eye being a pair of which only one is open at any given time. I seem to remember seeing some wildlife film of an animal bobbing its head around apparently for this reason.

You can also get some 3D data by being aware of how you need to focus the light from an object to get it sharp. However, people with only one eye (my brother is almost blind in one eye..) find it almost impossible to do things that need good 3D perception (like juggling) and in the UK are banned from driving huge trucks for this reason.

As for the idea that we could be simply unaware of other dimensions, has anyone read Flatland? It's a really good book for tackling this issue. It describes what happens when a 2D world is visited by a 3D object, which is a perfect way to make you think about how we would relate to a 4D world.
« Last Edit: 16/06/2004 12:40:33 by valley »
 

Offline OmnipotentOne

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Re: Do we see the world as it really is ?
« Reply #8 on: 17/06/2004 00:13:12 »
I think I read somwhere that in the blindspot in our eye, our brain fills it in with what it "thinks" go's there, all of a sudden I dont trust airplane pilots.

FLATLAND, I love that book! Theres so many remakes of it today.  Its just so funny how the book actually has a plot, and 2-dimensional characters.

I really dont like this kind of thinking, then again I do!  It contradicts everything I was ever tought, or what I thought had to be true, a real EYE opener for ya!

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Offline valley

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Re: Do we see the world as it really is ?
« Reply #9 on: 17/06/2004 19:05:32 »
There are some really nice blindspot experiments. You almost certainly know the old one where you draw two spots on a piece of paper, about 20cm apart, shut one eye, stare at one spot and move the paper until the other disappears (which is when its light is hitting your retina at the blind-spot). The interesting thing is when it's not a blank piece of paper, if the paper has lines on it, you will notice that your brain fills in lines where the now invisible spot is. If the paper is blue, the space will look blue. So, you think that your brain is constructing a visual image to fill the gap... well, the most interesting experiment of all is if the paper is covered in writing. People doing this (haven't got around to it myself, must do so!) say that the space is filled with writing. Fine, so what letters are in there?! When asked, they just say that they can't tell, but they do know it's writing. So your brain isn't really filling in an image, but describing that area as "blue paper" or "lined paper" or "writing" - you really see a lot less than you might think you do. Beautiful experiment.
 

Offline chris

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Re: Do we see the world as it really is ?
« Reply #10 on: 18/06/2004 07:54:27 »
Indeed. Also, have a look at this example of cortical manipulation of what you "think" you are seeing - it's called colour constancy and is a consequence of higher visual processing :

http://www.thenakedscientists.com/HTML/articles/article/martinwestwellcolumn9.htm

Chris

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Offline qazibasit

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Re: Do we see the world as it really is ?
« Reply #11 on: 25/06/2004 16:16:44 »
No i dont think that we see the world as it really is because we see this world in 3 dimension and the actual world is in 4th dimension so if we can see the world in 4th dimension then only we will see the real world.
 

Offline neilep

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Re: Do we see the world as it really is ?
« Reply #12 on: 25/06/2004 19:58:21 »
You've lost me there Abdul....what is the fourth dimension ?...do you mean time ?...if so then in my laymans point of view I think the only way you can see time is the passing of it via a clock.....sorry if I've misunderstood you but perhaps you can elaborate further.......thanks.

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Offline qazibasit

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Re: Do we see the world as it really is ?
« Reply #13 on: 26/06/2004 16:37:18 »
no not seeing the time passing by but seeing the objects with their frame of reference (their current velocity and their current time) and if you can see the things in this way then only you will see the actual world coz then you will have the access to place that thing in different time.
 

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Re: Do we see the world as it really is ?
« Reply #13 on: 26/06/2004 16:37:18 »

 

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