Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: redsniper on May 09, 2011, 09:35:02 pm
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http://www.youtube.com/watch?v=piyY-UtyDZw&feature=player_embedded
Sensors in cat's brain show what the cat is seeing on a computer. Seriously. I just.. I don't even.. my mind...
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Amazing stuff, though the comment at the end that what the cat saw looked a bit 'catty' was more a product of human phsychology than cat ;)
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Well ****. This should have some interesting applications in the future.
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Well ****. This should have some interesting applications in the future.
Anyone else thinking... Spy Cat!!!!? :p
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Your pet is actually a security camera.
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that's creppy.
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I do wonder what a human produced image would look like, with the amount of dedicated face recognition we have.
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http://news.bbc.co.uk/2/hi/science/nature/471786.stm (http://news.bbc.co.uk/2/hi/science/nature/471786.stm)
"Monday, October 11, 1999 Published at 19:10 GMT 20:10 UK"
:I
(That is really cool though. Wonder why there isn't anything more recent about it?)
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http://www.youtube.com/watch?v=piyY-UtyDZw&feature=player_embedded
Sensors in cat's brain show what the cat is seeing on a computer. Seriously. I just.. I don't even.. my mind...
This is old news. Watch the first part of this (http://www.imdb.com/title/tt0899298/), it's on google video. Made back in 2006.
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I do wonder what a non-human produced image would look like, with the amount of dedicated face recognition we have.
Fixed, since our condition limits us.
This makes me wonder how much of what we perceive actually is that way.
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I have no interest in a non-human image. I am incapable of processing any other way.
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I have no interest in a non-human image. I am incapable of processing any other way.
Being able to process a human's visual data would have it's uses, take training as an example, with this kind of technology a member of training staff can run through a training exercise and trainees can see where they should be focusing their attention, likewise turn it around and fit the equipment to a student they can then run through the exercise and the trainer/examiner can see exactly what the student sees and where their attention is focused.
Also how about being able to drive your PC purely by being able to visually focus on an icon?
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I have no interest in a non-human image. I am incapable of processing any other way.
The image from retinal nerves is inlaid to visual cortex in a matrix shape. Thus the image's properties are mostly preserved and independent from which animal's brain the data is plucked out. This, of course, assuming a visual cortex that does preserve the matrix of image data; I wouldn't bet too much success reading the image data off an insect, frog or fish brain this way.
Nevertheless, the cat brain's species-specific abstract processing of the image is one way further still. The only things that are varied on the image are quality, field of view, colour depth and spectrum, but that is the same with any kind of camera equipment and we can adapt to it fairly well.
However, cool as this is, it is of fairly limited use; what I'm interested in is the inverse process - ability to insert image data into visual cortex. That would have an immense amount of applications, ranging from artificial visual perception to recreational virtual reality or enhanced reality purposes.
Technically if they are able to read the data from the visual nerve as it's presented at the visual cortex, they should be able to insert a stimulating matrix of electrodes to insert image data instead. It would of course be somewhat different than the actual human eye experience, but the brain is very adaptable - with sufficiently high-resolution matrix and ocular equipment, I'm quite sure that especially young children would get used to the artificial sight.
And think of what gadgets you could include in the ocular implement... zoom in, cable connectivity to different image data - hey, would you feel like plugging your brain to a ten metre space telescope? :p
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I have no interest in a non-human image. I am incapable of processing any other way.
The image from retinal nerves is inlaid to visual cortex in a matrix shape. Thus the image's properties are mostly preserved and independent from which animal's brain the data is plucked out. This, of course, assuming a visual cortex that does preserve the matrix of image data; I wouldn't bet too much success reading the image data off an insect, frog or fish brain this way.
Nevertheless, the cat brain's species-specific abstract processing of the image is one way further still. The only things that are varied on the image are quality, field of view, colour depth and spectrum, but that is the same with any kind of camera equipment and we can adapt to it fairly well.
I'm having trouble parsing your posts but I think you are being way too generous about how much information is actually present in the raw input to the brain. Most of vision is a mirage introduced by neural processing using evolved rules. Pulling the raw information a cat sees isn't going to tell us much about what a cat sees at all.
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I'm having trouble parsing your posts but I think you are being way too generous about how much information is actually present in the raw input to the brain. Most of vision is a mirage introduced by neural processing using evolved rules. Pulling the raw information a cat sees isn't going to tell us much about what a cat sees at all.
That's very true, and I don't know the specifics of how this operation actually works.
I do know I've read from some source that I can't remember now that the retinal data is directly projected on an area of visual cortex, but obviously due to relative crudeness of eyes as an observation instrument (lots of pixels in the yellow spot, little pixels on the outside, colour data only on the center, etc.), the quality of the image projected and captured on the brain would suffer accordingly, which was demonstrated on the video.
Tapping into the higher brain processes that do the visual filtering and abstract handling of information would be even more advanced than hooking up to the direct datastream in the form it arrives to the visual cortex, so I'm assuming that's what they're doing. They probably have filters to handle saccades and to reconstruct the image from the data to a remarkable extent, and clearly it is working... somewhat.
That doesn't mean it's "what the cat sees"; more like "what the cat is watching", filtered through the eye, ocular nerve, signal capture and handling and possible post-processing.
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I'm having trouble parsing your posts but I think you are being way too generous about how much information is actually present in the raw input to the brain. Most of vision is a mirage introduced by neural processing using evolved rules. Pulling the raw information a cat sees isn't going to tell us much about what a cat sees at all.
That's very true, and I don't know the specifics of how this operation actually works.
I do know I've read from some source that I can't remember now that the retinal data is directly projected on an area of visual cortex, but obviously due to relative crudeness of eyes as an observation instrument (lots of pixels in the yellow spot, little pixels on the outside, colour data only on the center, etc.), the quality of the image projected and captured on the brain would suffer accordingly, which was demonstrated on the video.
Tapping into the higher brain processes that do the visual filtering and abstract handling of information would be even more advanced than hooking up to the direct datastream in the form it arrives to the visual cortex, so I'm assuming that's what they're doing. They probably have filters to handle saccades and to reconstruct the image from the data to a remarkable extent, and clearly it is working... somewhat.
That doesn't mean it's "what the cat sees"; more like "what the cat is watching", filtered through the eye, ocular nerve, signal capture and handling and possible post-processing.
I'm digging back a few years of memory to neuropsych lectures (and my memory may be slightly faulty), but as I recall the majority of our sight actually occurs in the brain as a result of image interpretation, rather than what is directly received into the eye (and try to disprove that tautological hypothesis, I dare you... :P). It's true that the primary visual cortex appears to receive a lot of direct data from the receptor cells in our retinae, and areas of the retinae superficially map to the surface layers of the cortex, but that isn't what we actually "see." So back to your original post, it would be unnecessarily cumbersome to try to insert an image into the "input" end of the visual cortex (and as that part of the brain engages in parallel processing instead of directional flow of information, impossible). It would make much more sense to try the insertion at the point where the assembled visual information is being interpreted. Otherwise, our built-in processing rules would disrupt what you want to display.
Like Battuta, deciphering your original post is proving somewhat challenging for me so maybe that's what you were saying to begin with. Image insertion at output of visual cortex = practical.
Sight is mostly perception and interpretation, not a true reflection of what exists in our surroundings. (Who needs illicit drugs when you have neuropsych to do the mindfrak for you :P)
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So back to your original post, it would be unnecessarily cumbersome to try to insert an image into the "input" end of the visual cortex (and as that part of the brain engages in parallel processing instead of directional flow of information, impossible). It would make much more sense to try the insertion at the point where the assembled visual information is being interpreted. Otherwise, our built-in processing rules would disrupt what you want to display.
I disagree with you.
Fortunately this is science and there is one way we can settle this.
TO THE THUNDER DOME lab!
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I'm digging back a few years of memory to neuropsych lectures (and my memory may be slightly faulty), but as I recall the majority of our sight actually occurs in the brain as a result of image interpretation, rather than what is directly received into the eye (and try to disprove that tautological hypothesis, I dare you... :P). It's true that the primary visual cortex appears to receive a lot of direct data from the receptor cells in our retinae, and areas of the retinae superficially map to the surface layers of the cortex, but that isn't what we actually "see." So back to your original post, it would be unnecessarily cumbersome to try to insert an image into the "input" end of the visual cortex (and as that part of the brain engages in parallel processing instead of directional flow of information, impossible). It would make much more sense to try the insertion at the point where the assembled visual information is being interpreted. Otherwise, our built-in processing rules would disrupt what you want to display.
Like Battuta, deciphering your original post is proving somewhat challenging for me so maybe that's what you were saying to begin with. Image insertion at output of visual cortex = practical.
Sight is mostly perception and interpretation, not a true reflection of what exists in our surroundings. (Who needs illicit drugs when you have neuropsych to do the mindfrak for you :P)
Well, I just can't personally see how it could be possible to make a generalized signal format that would actually be a match with the signals that visual cortex outputs as the WYSIWYG data. It would, by my understanding, have a lot more variation between different people - correct me if I'm wrong, but do we even have a clear concept where the visual cortex dumps the complete "visual perception image stream" that it reconstructs from the fragmented datastream from the retinas? What happens next and what format is the image data at this point?
I think visual cortex would have easier time to adapt into processing raw video signal, mimicking the ocular nerve inputs, than us figuring out what sort of info the visual cortex reconstructs from the sensory inputs from the eyes. It just feels likely to me that at this level, the data would be highly specialized and abstract rather than anything resembling raw image data, so even if you managed to patch together some software that mimics the functionality of visual cortex in reconstructing the ocular signals into a brain-comprehensible visual perception data, you'd likely start having latency problems without very powerful image processing units as well as the probable problems trying to adapt the system for general purpose rather than individually tailored for use.
It just feels like it would be a simpler solution to let the brain do the heavy lifting: Try to calibrate the input signal to visual cortex to match as closely as possible the qualities of a biological eyes' retinal inputs, and let the subject's brain adapt to it and learn to process and reconstruct a visual perception from that data. The brain is so far uniquely powerful and adaptable marvel of signal processing, so I bet it'd do the job better and faster than trying to bypass the image reconstruction phase done by the visual cortex. Of course, it would not be quite the same as the "natural" vision due to differences between signals from natural eyes and artificial ocular implants, but especially if the implantation surgery was done at young age, I think it would have spectacular resources... ignoring the current practical difficulties of hooking up raw image stream to the brain at sufficient and meaningful resolution.
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Well, I just can't personally see how it could be possible to make a generalized signal format that would actually be a match with the signals that visual cortex outputs as the WYSIWYG data. It would, by my understanding, have a lot more variation between different people - correct me if I'm wrong, but do we even have a clear concept where the visual cortex dumps the complete "visual perception image stream" that it reconstructs from the fragmented datastream from the retinas?
Not reconstructs, really. More or less just...constructs.
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well, my money is on RLE encoding with 7/5/5 HSL color space, I'm only putting down 5 bucks but if I win the odds will make me a billionaire.
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Not reconstructs, really. More or less just...constructs.
I'm treating the original scenery as an image that the eye as an optical device observes.
That image is reconstructed into visual perception by the visual cortex, rebuilding it from the fragmented saccadic observations of the eye, which constantly update the "expired" sections of the image, creating a more or less seamless illusion of continuous image.
If you consider the visual cortex' job as the actual image (rather than the reality beyond the observer's eye), then your choice of verb is valid, of course.
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Not reconstructs, really. More or less just...constructs.
I'm treating the original scenery as an image that the eye as an optical device observes.
That image is reconstructed into visual perception by the visual cortex, rebuilding it from the fragmented saccadic observations of the eye, which constantly update the "expired" sections of the image, creating a more or less seamless illusion of continuous image.
You're still making the mistake of thinking that the image that eventually reaches you is somehow reconstructed from information retrieved from outside. It's not. The minimal information the eye delivers is fed into this huge mechanism that then fabricates the vast majority of what you see from whole cloth (obeying evolved rules) and produces a useful image which we can use to navigate and manipulate our environments.
The image isn't necessarily 'true' in that it reflects some objective reality - it's not reconstructed. It's a signal, a very rich form of symbolism. What we see as a right angle maps nicely to the form and function of a right angle, but 'the look of a right angle' isn't something that exists outside the brain.
If you consider the visual cortex' job as the actual image (rather than the reality beyond the observer's eye), then your choice of verb is valid, of course.
I don't think there's any 'reality' to vision outside the visual cortex. Vision is like a HUD. It's a bunch of labels that allow us to behave usefully, applied to a very narrow stream of information.
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You're still making the mistake of thinking that the image that eventually reaches you is somehow reconstructed from information retrieved from outside. It's not. The minimal information the eye delivers is fed into this huge mechanism that then fabricates the vast majority of what you see from whole cloth (obeying evolved rules) and produces a useful image which we can use to navigate and manipulate our environments.
The image isn't necessarily 'true' in that it reflects some objective reality - it's not reconstructed. It's a signal, a very rich form of symbolism. What we see as a right angle maps nicely to the form and function of a right angle, but 'the look of a right angle' isn't something that exists outside the brain.
I don't think there's any 'reality' to vision outside the visual cortex. Vision is like a HUD. It's a bunch of labels that allow us to behave usefully, applied to a very narrow stream of infromation.
It doesn't really matter, though. If what you say is true, the visual cortex could patch up a convincing visual perception using any image source that it gets used to, whereas trying to mimic that patching process is likely to fail hard.
Will you at least agree that up to the input onto the visual cortex, the information from the eye is essentially an image that was focused on the retina by the cornea and lens of the eye, then translated via ocular nerve to the visual cortex where it fires up neurons in approximately the same pattern as the original image on the retina?
What happens after that doesn't really matter to me. It strikes me as the easiest way to achieve artificial sight would be to mimic the process of projecting image data as input to visual cortex, and letting the brain take care of the rest however it wants to fool itself into thinking it as a natural visual perception.
By the way I disagree with your statement - we receive quite a bit of information visually, and even though it's not momentarily nearly full field of vision, it's completed by the brain quite effectively.
And if you refer to the question whether we "see" things similarly - whether we all see red similarly, or just identify it as "red" because it's the label we've given it - in my opinion, yes, we see it similarly up to the point where information enters visual cortex. And that the visual cortex patches the image data into a full field of view vision, I don't really care how our more abstract thought processes handle it, but the sensory stimulus is identical.
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By the way I disagree with your statement - we receive quite a bit of information visually, and even though it's not momentarily nearly full field of vision, it's completed by the brain quite effectively.
I don't think it's a matter of opinion. Properties like color do not exist outside the brain, they're synthesized from physical information and used (imprecisely) to signal it.
And if you refer to the question whether we "see" things similarly - whether we all see red similarly, or just identify it as "red" because it's the label we've given it - in my opinion, yes, we see it similarly up to the point where information enters visual cortex. And that the visual cortex patches the image data into a full field of view vision, I don't really care how our more abstract thought processes handle it, but the sensory stimulus is identical.
I haven't commented on that question, nor on the question of where input should be introduced to create artificial visual input.
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I don't think it's a matter of opinion. Properties like color do not exist outside the brain, they're synthesized from physical information and used (imprecisely) to signal it.
but I can quantify color, how can I quantify a completely fictitious property?
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I don't think it's a matter of opinion. Properties like color do not exist outside the brain, they're synthesized from physical information and used (imprecisely) to signal it.
but I can quantify color, how can I quantify a completely fictitious property?
Color is a consensual hallucination based on actual, objective physical properties. The fact that we all share the same color wiring makes it easy for us to establish consensual measures, and it's even easier to quantify the physical properties color is based on.
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yeah, but if there were an alien that had completely different perceptions of color than we did, we would still be able to communicate in numbers the color given off by an electron moving from the second to the first energy level in a hydrogen atom. you could make the same argument for anything we sense.
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yeah, but if there were an alien that had completely different perceptions of color than we did, we would still be able to communicate in numbers the color given off by an electron moving from the second to the first energy level in a hydrogen atom. you could make the same argument for anything we sense.
No we wouldn't. You're confusing color (which is a constructed property based on multiple physical traits) with the wavelength of light.
Wavelengths do not map correctly to colors.
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please elaborate.
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The sun is yellow but it looks white.
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please elaborate.
I was going to post this longass thing about L and S cones but basically this does a far better job. (http://webvision.med.utah.edu/book/part-vii-color-vision/color-vision/)
tl;dr version, very different combinations of wavelengths can appear as the same color for reasons which are entirely resident in our eyes and brains. Color does not map 1:1 bidirectionally to wavelength.
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Will you at least agree that up to the input onto the visual cortex, the information from the eye is essentially an image that was focused on the retina by the cornea and lens of the eye, then translated via ocular nerve to the visual cortex where it fires up neurons in approximately the same pattern as the original image on the retina?
I'll interject again here - no. The retina performs perception/interpretation functions. The original image pattern is lost as light strikes the photoreceptors. What lights up on the surface of the visual cortex is the photoreceptor firing pattern, which is not a true pattern of the original image. Due to their method of data collection, photoreceptors "perceive" rather than "observe."
Human (and other related animal) sight has biological consensus due to evolution, but sight gives us a [consensual] perception of the world, not an observation. Battuta has been discussing this.
Try to calibrate the input signal to visual cortex to match as closely as possible the qualities of a biological eyes' retinal inputs, and let the subject's brain adapt to it and learn to process and reconstruct a visual perception from that data. The brain is so far uniquely powerful and adaptable marvel of signal processing, so I bet it'd do the job better and faster than trying to bypass the image reconstruction phase done by the visual cortex. Of course, it would not be quite the same as the "natural" vision due to differences between signals from natural eyes and artificial ocular implants, but especially if the implantation surgery was done at young age, I think it would have spectacular resources... ignoring the current practical difficulties of hooking up raw image stream to the brain at sufficient and meaningful resolution.
I think the trouble there is that the brain may inadvertently try to apply its processing rules in a way we can't anticipate. It's a technological hurdle that we'll all just have to wait and see on =) If I remember correctly, though (and this is a HUGE if, this class was 5 years ago), the visual cortex does perform a consolidation of visual perception before shipping that information out to the rest of the brain.
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You're confusing color (which is a constructed property based on multiple physical traits) with the wavelength of light.
The fact that "colour" is a constructed property rather than a physical characteristic of an object, I found very interesting. :)
Now that I think about it, I learned recently that the Mantis Shrimp (http://en.wikipedia.org/wiki/Mantis_Shrimp) (which was an animal I already liked due to its powerful claws and all the funky effects that they cause) can see more "colours" than any other known animal.
But I'm probably going a bit off-topic on that point.
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I dun care I just want my Ghost in the Shell cyber eyes dammit
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Cover one eye for a while and stare at a bright light (not the sun, lol). Then look around and swap between both eyes. Colors between the two will look quite different. :)
What we perceive as color is not only not a direct function of wavelength (rather it depends on many values, as Battuta said), but it also varies on the relative color and intensity of the ambient light that your eyes are currently adapted to.
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Certainly colour perception is a result of multiple things, and it's affected by what else we see in the image (hence the colour-distorting visual illusions) but I still maintain my view that colour is primarily a function of wavelength of photons and the spectral spread of the light arriving to the retina. The fact that our perception alters colours depending on different stuff doesn't make the property of colours any less real.
Leaves are green because they have no use for the green wavelengths and mostly reflect them, while absorbing the blue and red wave lengths.
A monochromatic beam of light would be identified correctly within the limitations of our system.
The fact that our brain does signal processing doesn't mean it invents all the qualities in the image we see. A rectangle is a rectangle in reality, and if it reflects red light and absorbs others (or even emits red light in otherwise dark room) then its colour is red. It's not some imaginary quantity that our brain just plasters on, it's a perceived property corresponding to physical property and I don't see how it's relevant to say that there's "no colour" in external world.
I can agree that perceived colour is a mix of not only the wavelength spread of the light but also the context in which it's seen, physical surface structure (diffuse, shiny, emitted or reflected light), environment's lighting (is the object in a shadow or direct light), but that just means our image processing facilities combine these features with each other to give us more information than just the spectral spread of light that an object emits or reflects.
The information about retina already doing image processing is interesting. I always considered retina more or less like a digital camera cell with four types of pixels, one sensitive to light and three to different wavelengths of light.
watsisname: the phenomenon you are talking of is analogous to white balance adjustments on cameras. The level of low light acclimatization shifts the white balance, so if your eyes are at different setting, obviously the perception shifts around. It's like setting one camera to daylight and one to fluorescent and complaining that the images have different colours.
By the way, almost same phenomenon can be achieved by staring through cyan/red anaglyph stereo glasses for a while. Eyes and the brain try to compensate for the saturation of those particular colours, so when you take the glasses off, the red lens eye sees things more cyan, and the cyan lens eye sees things more reddish. It is fascinating phenomenon.
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the phenomenon you are talking of is analogous to white balance adjustments on cameras. The level of low light acclimatization shifts the white balance, so if your eyes are at different setting, obviously the perception shifts around. It's like setting one camera to daylight and one to fluorescent and complaining that the images have different colours.
Oh I'm not complaining -- white balance and dark adaptation are both fantastic evolutionary developments. :) I was simply stating that an individual's color perception is not constant.
On a semi-related note, another interesting vision-related concept I discovered was back when I acquired my 405nm violet laser. It has the same output power as my other, 532nm green one (~150mW), but it appears to be much, much fainter because this particular wavelength of violet is very close to the limit of a human's ability to detect. It's just really weird to me to see two dots of light side by side, one of them looking significantly brighter than the other, but knowing that they are in fact the same (easily confirmed if the violet laser is shined at something that converts violet light into blue or green).
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Colours are formed because our eyes have three types of receptors, red, green and blue. They mix together and inform the brain about this mix with a myriad of colors.
TV sets use the exact same reconstruction of colours in RGB not because "RGB" is a fundamental law of physics, but because they mirror our photoreceptors pretty well. An animal who would have different photoreceptors would probably not be able to see TV very well.
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please elaborate.
What's the wavelength for magenta?
Clue: Magenta is a product of our minds, literally.
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Clue: Magenta is a product of our minds, literally.
Not really. It can be pretty well quantified, even if it isn't a spectral colour.
What's the wavelength of white?
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Clue: Magenta is a product of our minds, literally.
Not really. It can be pretty well quantified, even if it isn't a spectral colour.
What's the wavelength of white?
The important thing to grasp is that there are multiple ways to arrive at each color, which means there is no 1:1 mapping between color and wavelength. You can't look at a given color and know what wavelength of light produced it.
This makes color a good tendentious signal but still a construct.
So, to dissect one of your examples
The fact that our brain does signal processing doesn't mean it invents all the qualities in the image we see. A rectangle is a rectangle in reality, and if it reflects red light and absorbs others (or even emits red light in otherwise dark room) then its colour is red.
You've constructed a false 1:1 mapping here. It could be reflecting any type of light that sums to red on the CIE chromaticity diagram. There's a whole space of physical properties that rectangle could have which could lead it to reflect all sorts of different light but they would end up as red.
It's not some imaginary quantity that our brain just plasters on, it's a perceived property corresponding to physical property and I don't see how it's relevant to say that there's "no colour" in external world.
It's a perceived property corresponding to multiple physical properties and it could mean any one of them. Ergo, there is no color in the external world; color is a construct which can signal multiple things.
There is no color in the external world.
ed:
This statement is also factually false:
I can agree that perceived colour is a mix of not only the wavelength spread of the light but also the context in which it's seen, physical surface structure (diffuse, shiny, emitted or reflected light), environment's lighting (is the object in a shadow or direct light), but that just means our image processing facilities combine these features with each other to give us more information than just the spectral spread of light that an object emits or reflects.
because it implies a 1:1 mapping in which each combination of wavelength, physical surface structure, and environmental lighting produces a unique color (as you said, more information). This is untrue.
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I don't know if I'm formulating my arguments poorly, but I never suggested that one combination of physical attributes corresponded to only one perceived colour.
The fact that we can perceive different colours as the same doesn't mean that the external word doesn't have the attributes that make up the colour in our perception. And even if our brain can mix up a lot of stuff together and those things can alter our perception of what the colour appears as, that doesn't change the fact that the colours themselves do exist.
I don't understand the argument that they are just a product of some mental processing. Clearly they correspond to physical attributes of the objects we observe.
A rose by any other name...
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I don't know if I'm formulating my arguments poorly, but I never suggested that one combination of physical attributes corresponded to only one perceived colour.
The fact that we can perceive different colours as the same doesn't mean that the external word doesn't have the attributes that make up the colour in our perception. And even if our brain can mix up a lot of stuff together and those things can alter our perception of what the colour appears as, that doesn't change the fact that the colours themselves do exist.
No, it doesn't - in fact you're defeating your own argument internally, right here in the sentence:
The fact that we can perceive different colours as the same
You can perceive different sets of the physical traits that determine color as the same color. You're talking about color as if it's something that exists outside the head but it's not. Saying 'that object is yellow' gives very little information about an object's physical properties - it simply places it in one area of the CIE diagram. It restricts its properties to a set with considerable variability.
And again, here:
even if our brain can mix up a lot of stuff together and those things can alter our perception of what the colour appears as
You speak of altering as if there were an objective color which is then altered or moved by the brain's perceptive filters. But there is no such thing. All that exists, objectively, are the traits which are used to generate color - and multiple sets of those traits can lead to the same color.
I don't understand the argument that they are just a product of some mental processing. Clearly they correspond to physical attributes of the objects we observe.
Color does not correspond in a 1:1 fashion. There is no clean bidirectional mapping.
Let's say we create the color 'hooligans'. Hooligan colored objects are objects which possess legs OR tentacles AND bone OR cartilage. A hooligan object could have legs and cartilage, or it could have tentacles and bone. But the definition of hooligan exists only in the rule we have established to define hooligan. You could not build a hooligan meter without first establishing that rule.
Similarly, a machine or alien could not understand our perception of color without being transmitted the rules we use to create color. It could, of course, objectively measure the physical properties that we use to construct color, but it would have no way to arrive at the concept of color from there unless it dissected a human mind, because the rules do not proceed from the physical properties in a trivially mappable fashion.
Ergo, color does not exist outside the human mind.
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"Colours themselves do exist".... do you see where I am getting at, Battuta, when I say that people are still deluded my metaphysical thinking? :lol:
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"Colours themselves do exist".... do you see where I am getting at, Battuta, when I say that people are still deluded my metaphysical thinking? :lol:
No.
Colors do exist. They're an obvious, measurable property. They're just a property of the signal processing of the human mind, rather than the external world.
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Nah, I don't think that's right.
I agree that colour perception is largely an internal process. However, your claim that because several different mixes of attributes can appear as the same colour, colours somehow don't exist in reality is false. It's merely demonstrative of the limitations of our visual perception - we can't make a distinction between the two things so our brain dubs them the same colour, but that doesn't mean it's somehow an incorrect distinction.
I can see the value in your argumentation, but I think our definition of colour is a bit different.
Let's try this:
(http://img859.imageshack.us/img859/6917/cyanred.png) (http://img831.imageshack.us/img831/9117/greenmagenta.png) (http://img684.imageshack.us/img684/5718/yellowbluex.png)
Here we have three dithered fields. Each field consists of blocks of four pixels, enlarged in the upper left corner for each picture.
These appear as the same grey colour. Why? Because on each image we have a situation where every other pixel has two sub-pixels lit up, and every other pixel only one.
On our display hardware, every square should render identically as far as the light intensity goes, and it should appear the same level of grey.
Now, our ability to see colours on computer screen hinges on dithering; our inability to distinguish sub-pixels as individual entities makes it possible to mix red, green and blue in varying quantities to produce a more or less wide gamut of colours.
However, the fact that our rendering displays render all three images similarly doesn't mean they are the same. Their individual properties are different, and each is made of completely different colours pixel-wise, as zooming in reveals.
Now if I were to compare the display to our visual perception, one could say that both arguments have value: All objects are grey in our display, but they don't have grey in reality - hence the greyness is an illusion caused by our display hardware.
The other argument says that each of the objects still have individual colours. One made of cyan and red, one made of green and magenta, and one made of yellow and blue. The fact that display renders them similarly doesn't mean the images themselves don't have these properties.
I don't know if this portrays what I'm trying to say: I'm saying that colour as a physical property does exist in various ways and we can identify them, but limitations in our perception sometimes make us identify various physical properties as the same colour.
You're saying that colour as a concept exists just inside our heads. In my opinion, this undermines the abilities of human visual perception quite a bit, because even though it is limited, it still can distinguish between quite a bit of clearly differently coloured objects.
You could say that my concept of colour is primarily involved in the physical side of things rather than psychological or neurological perception. Mixtures of properties aside, we can still identify spectral colours correctly within the visible spectrum...
TL;DR:
You say because we identify various properties as same colours, colours don't exist.
I say there are more colours than we can identify, and thus some identify as the same.
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we can't make a distinction between the two things so our brain dubs them the same colour, but that doesn't mean it's somehow an incorrect distinction.
If you're still misunderstanding things this early in the process I ask that you please do some research on the topic before we continue this discussion.
If you can explain to me how an alien or machine would perceive color using only objective measurements perhaps you can make some headway.
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If you can explain to me how an alien or machine would perceive color using only objective measurements perhaps you can make some headway.
The measurements done by a digital camera's sensor seem pretty objective to me.
However, it obviously doesn't "perceive" the colours, it's a sensor and data storage instrument. To handle the data you would need to have some sort of processing unit that would analyze the image with some purpose.
For example, you could give a robot a task of identifying objects with some colour from the image to separate them from rest of the objects. That'd require a primitive way to perceive the image to distinguish objects in it in the first place...
You could do that by either giving them an RGB colour code with error bars to look for; most likely you wouldn't get very good results with just this method because the colour values on the image would depend on lighting, position of the object, angle of the surfaces etc... but with standardized lighting, you could get relatively good results in controlled conditions.
To make things more accurate and independent of environment, you would probably have to code something that would build a three-dimensional space of the image, separate differently coloured and contrasted parts from the image into individual objects, place them into the 3D space, read their shape, compensate for the lighting making upper parts of objects brighter and lower parts darker, check if the object has any specular glints disturbing the colour analysis, neutralize them based on the interpreted shape of the image, and THEN compare the compensated colour with the target colour to define if the surface of the objects themselves matches the desired colour parametres closely enough.
If I misunderstood what you're after, you'll need to define the word "perceive" for me... :p
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If you can explain to me how an alien or machine would perceive color using only objective measurements perhaps you can make some headway.
The measurements done by a digital camera's sensor seem pretty objective to me.
I'm fairly sure there is no color in a digital camera image. There are recorded objective properties. Color is introduced by the human looking at the image.
For example, you could give a robot a task of identifying objects with some colour from the image to separate them from rest of the objects. That'd require a primitive way to perceive the image to distinguish objects in it in the first place...
You could do that by either giving them an RGB colour code with error bars to look for; most likely you wouldn't get very good results with just this method because the colour values on the image would depend on lighting, position of the object, angle of the surfaces etc... but with standardized lighting, you could get relatively good results in controlled conditions.
You're still not talking about color here. You're discussing properties like the wavelength of reflected light.
How would a machine or alien, using an objective sensor that detects the wavelength of light, perceive color?
Allow me to quote Wikipedia.
Two different light spectra that have the same effect on the three color receptors in the human eye will be perceived as the same color. This is exemplified by the white light emitted by fluorescent lamps, which typically has a spectrum of a few narrow bands, while daylight has a continuous spectrum. The human eye cannot tell the difference between such light spectra just by looking into the light source, although reflected colors from objects can look different
Simply measuring wavelengths, it is impossible to arrive at the perception of color the human eye and brain generates. The two different light spectra described in the quote would appear to an alien or machine as two different light spectra. They would have no reason to consider these the same colors, any more than an observer looking at two objects, one with cartilage tentacles and one with bone limbs, would have any reason to consider them both hooligans.
You need the definition of 'hooligan' in order to identify the group 'hooligan'. You need the definition of a color in order to identify the color. It does not exist without that coding.
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You need the definition of 'hooligan' in order to identify the group 'hooligan'. You need the definition of a color in order to identify the color. It does not exist without that coding.
If it exists, it doesn't need a definition from us to exist, just for us to perceive it.
You're essentially saying that because we identify several different things as the same colour, colour doesn't exist outside our definitions for them.
I say we don't have enough definitions for all the colours in the world, but they exist outside our definitions of them.
It seems we are at an intellectual impasse.
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You need the definition of 'hooligan' in order to identify the group 'hooligan'. You need the definition of a color in order to identify the color. It does not exist without that coding.
If it exists, it doesn't need a definition from us to exist, just for us to perceive it.
You're essentially saying that because we identify several different things as the same colour, colour doesn't exist outside our definitions for them.
I say we don't have enough definitions for all the colours in the world, but they exist outside our definitions of them.
It seems we are at an intellectual impasse.
Far from it. You're trying to make a speculative argument about something that is quite grounded and measurable. The response curves of receptors in the eyes can be measured. The human visual system simply does not distinguish within a color; it treats all inputs that create the same response pattern as the same color.
You can break down all the possible wavelengths which create, say, magenta into subunits, and name each of those individually - but then you're simply not talking about color any more; you've moved on to something else, something not perceived by the human visual system.
If you want to discuss color, you need to discuss color. Color is, by definition, perceptual. You cannot make an argument that relies on the extraperceptual. We can measure what is perceived. And that measurement is quite clear.
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If you want to discuss color, you need to discuss color. Color is, by definition, perceptual. You cannot make an argument that relies on the extraperceptual. We can measure what is perceived. And that measurement is quite clear.
I disagree. To me, colour as a property of objects is something substantial, which we perceive in a limited fashion.
I don't agree with binding the definition of colour simply to our perception of it. Clearly the combinations of properties that make us identify them as a colour are quite real.
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If you want to discuss color, you need to discuss color. Color is, by definition, perceptual. You cannot make an argument that relies on the extraperceptual. We can measure what is perceived. And that measurement is quite clear.
I disagree. To me, colour as a property of objects is something substantial, which we perceive in a limited fashion.
I don't agree with binding the definition of colour simply to our perception of it. Clearly the combinations of properties that make us identify them as a colour are quite real.
Now you're simply wrong - using the wrong words to discuss the wrong things. Color does not exist as a property of objects; we've already demonstrated this. You cannot find and point to a red object. You can find an object with the set of properties that generates the perception of red, but not all red objects will have these properties. 'Red' does not become meaningful until the eye and brain are introduced into the system.
Attempting to make a philosophical argument here is pointless; there is simply no room for philosophy to inject itself. You are free to come up with your own definition of the word color and ascribe whatever properties you like to it, of course, but it will remain orthogonal to any discussion of color in the sense of physics and psychophysics.
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Define 'red' as a unitary group without using a single characteristic of the human eye or brain and maybe you'll convince me. That's your mission.
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Now you're simply wrong - using the wrong words to discuss the wrong things. Color does not exist as a property of objects; we've already demonstrated this. You cannot find and point to a red object. You can find an object with the set of properties that generates the perception of red, but not all red objects will have these properties. 'Red' does not become meaningful until the eye and brain are introduced into the system.
An object that emits 620 nm photons is a red light. I doubt there's any simpler way to describe redness. It's a good way to describe this property, albeit not quite as accurate as just calling it 620 nm monochromatic light.
Of course this simplicity is limited to spectral colours, which are an easy case, but the mixtures that make up additive colours are equally real combinations, and not calling them colours would just be an unnecessary complication.
So, I prefer to call them colours, and our perception of them is the perceived colour.
Attempting to make a philosophical argument here is pointless; there is simply no room for philosophy to inject itself. You are free to come up with your own definition of the word color and ascribe whatever properties you like to it, of course, but it will remain orthogonal to any discussion of color in the sense of physics and psychophysics.
I might be suggesting that coconuts migrate, but it doesn't really interest me to say that colour doesn't exist in world until we perceive it.
To me it's the same argument as whether there's a sound if there's no one to hear it, and I don't see the point in it. The physical qualities that cause us to detect a colour will be there regardless of our colour perception.
Our colour perception is just our way to label them, but because of the limitations of our sensory systems we can't label them all. The colours as properties of light would still exist just the same if we were all blind and used echolocation as our primary sense.
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Define 'red' as a unitary group without using a single characteristic of the human eye or brain and maybe you'll convince me. That's your mission.
Simplest definition for red would be light that activates the red receptors in retina, but not green and blue receptors.
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An object that emits 620 nm photons is a red light. I doubt there's any simpler way to describe redness. It's a good way to describe this property, albeit not quite as accurate as just calling it 620 nm monochromatic light.
But a red light is not an object that emits 620nm photons; therefore this definition is incomplete. You give a better definition below which also proves my point.
So, I prefer to call them colours, and our perception of them is the perceived colour.
It's nice that you prefer this, but I can prefer to call neutrons protons and protons neutrons and it'd still have no place in a discussion of the topic.
Our colour perception is just our way to label them, but because of the limitations of our sensory systems we can't label them all. The colours as properties of light would still exist just the same if we were all blind and used echolocation as our primary sense.
No, they wouldn't, because the properties of light do not map to the colors and the colors do not exist without our senses. If you're talking about something you invented called 'colors as properties of light' which simply means 'properties of light', fine, but the whole point of this discussion is that that is not color.
Simplest definition for red would be light that activates the red receptors in retina, but not green and blue receptors.
Exactly. Now you've nailed it.
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Whoa. Maybe I can phrase this in a different way and reduce some confusion.
Wavelength is a property of light by which the quality of the light can be quantified. All light has a wavelength associated with it. Wavelengths are measurable in quite a number of ways. It is an objective value associated with a physical property.
Colour is the rough approximation that all species with eyes attribute to particular wavelengths. The wavelength(s) that define a particular colour are not universal to all species. Colour is perception of a wavelength; wavelength is objectively measurable, whereas colour is not (as it requires interpretation).
Simplest definition for red would be light that activates the red receptors in retina, but not green and blue receptors.
Not entirely true. For one, humans have four photoreceptor pigments. Second, they have peak absorption wavelengths and absorption curves. Third, those curves overlap. Fourth, the curves don't actually correspond to any single colour that we perceive, as the receptor proteins absorb wavelength ranges that are quite specific to evolutionary fitness (human photopsins have peak absorptions of wavelengths that we perceive as yellow-green, green, and blue-violet; rhodopsin picks up green-blue light and allows for sight in low-light conditions) This is part of what I was getting at by saying photoreceptors perceive rather than observe light - different light conditions are capable of triggering the same response patterns in photoreceptor cell groups. Furthermore, colour perception requires at least two different types of photopsins to fire at once; the brain then interprets the different absorption curves to deduce colour from the wavelengths being absorbed.
Colour perception is an artificial construction of the brain to give meaning to wavelength and intensity. Colour names are just handy ways of interpreting light conditions; different conditions can produce the same colour perception without loss of information because our brains don't actually need to be able to distinguish those conditions, evolutionarily-speaking. Trichromatic vision evolved only in species that really need it; dichromatic species don't "see" an absence of a particular colour, because they have no perception of it. Perception of the colour "red" came about evolutionarily later than the other colours (red requires the longwave photopsin that actually reads colours we see as yellow) presumably as a result of changes in diet; a species than can distinguish the light conditions that ripe fruits reflect is going to have a much easier time ensuring it can eat. The yellow and yellow-green photopsins are quite genetically similar, leading to pretty solid hypothesis (that howler monkey species, some of which are dichromatic and some of which are trichromatic) seem to support.
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"Colours themselves do exist".... do you see where I am getting at, Battuta, when I say that people are still deluded my metaphysical thinking? :lol:
No.
Colors do exist. They're an obvious, measurable property. They're just a property of the signal processing of the human mind, rather than the external world.
Way to purposedly miss the point.
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I didn't get your point either. What on earth was it?
MP: Excellent post. The mechanics and evolution of dichromatic and trichromatic vision are very interesting. :)
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Not to dig up those squares again...but they appear as three distinct shades of gray to me. What does that mean from a perception standpoint? :p
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Do they really?
Sometimes I feel like one of them is a different shade, but it alternates, and if I continue staring at it lots of tracers and funky lines flow over the image and I start sweating real hard as a vortex opens and Bugs Bunny grins at me through it and now I can't leave my room but wait there is something on the wall oh wow it's so soft!
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Not to dig up those squares again...but they appear as three distinct shades of gray to me. What does that mean from a perception standpoint? :p
Read my last post on page 3 and you'll figure it out =)
Hint: Minimum 2 cones must fire to determine colour perception based on wavelength and intensity.
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No, I understand that...I just mean that Herra seemed to be suggesting that he saw all three boxes as the same exact shade, whereas I can tell them apart very easily. I was thinking it might be a monitor thing.
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No, I understand that...I just mean that Herra seemed to be suggesting that he saw all three boxes as the same exact shade, whereas I can tell them apart very easily. I was thinking it might be a monitor thing.
Oh!
Yeah, probably your monitor. I've looked at them on four different monitors today and they were all the same shade.
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I didn't get your point either. What on earth was it?
People here still confuse empirical reality for reality itself. They are thinking that if they are able to see RED, and name RED, and share the "experience" of RED with every other human being, that RED exists "by itself", "out there", even if humans didn't exist.
This is basic metaphysical thinking. The belief that "things exist beyond humans". At this point people get confused, and perhaps think that I'm a solipsist, that I think that the universe only exists when I think or live in it. It's way more subtle than that. It's semantical. The universe existed and will exist even if no humans exist any more, but by then the word "RED" becomes meaningless. Not because it "doesn't exist per se", but because that sentence becomes meaningless by itself.
"RED" is only meaningful to humans. You need humans to define "RED". You can even try to be utterly objective and declare that it is the wavelenght XPTO, but even that is hanging in a lot of human assumptions and needs. Rocks won't care about this definition.
This debate of what is color, and if it "exists" by "itself" is pretty old, and the term used for the experience of the color by humans is "QUALIA". Does QUALIA exist outside the human brain?
The thing that I was trying to say to Battuta is that people simply have too much difficulty in realizing that they cannot see things "as they are", because that is a metaphysical pipe dream. A meaningless platonic exercise. What we can do is formulate words that convey how we can explain the models we use that predict astonishingly well what happens when we open our eyes and what we see in the world. And that's all we need.
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Not to dig up those squares again...but they appear as three distinct shades of gray to me. What does that mean from a perception standpoint? :p
It probably means your display's calibration is not ideal. The basic mechanism behind those squares is that each pixel on your screen consists of three sub-pixels: Red, green and blue. Due to the values of colours, each sub-pixel is either on, or it is off.
Each pixel lit looks like this:
███
and each pixel shut down looks like this:
███
Cyan-red subpixel pattern looks like this:
██████
██████
Broken into sub-pixels, it looks like this:
███ ███
███ ███
When it repeats, it looks like this:
███ ██████ ███ ███ ███ ███ ███ ███ ███ ███ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ███ ███ ███ ███ ███ ███ ███ ███ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ███ ███ ███ ███ ███ ███ ███ ███ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ███ ███ ███ ███ ███ ███ ███ ███ ███
███ ██████ ██████ ██████ ██████ ██████ ███
So you can basically see that overall exactly half of the sub-pixels are lit, and half are shut down. This is effectively the exact same thing as dithering full white and full black pixels similarly; only the sub-pixel arrangement changes line by line.
This exact same distribution (with slightly varying subpixel order for each line) should repeat for all the squares, regardless of the colour of the pixels - the structure of the display renders them effectively similar to what dithered black-white checker board would be. Sub-pixel layout of your display will also effect the ordering of each lines (I used horizontal RGB layout which is I think the most common).
If your display doesn't do this, then I would look into some calibrations, specifically RGB gamma curves and possibly colour temperature, but I'm not certain what type of monitor would display the squares significantly differently... :nervous:
Also, my pixels are not square. :p
EDIT: Here are the yellow-blue and magenta-green patterns:
██████
██████
███ ███
███ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
██████
██████
███ ███
███ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
███ ██████ ██████ ██████ ██████ ██████ ███
The last one is particularly interesting because it spreads the sub-pixel distribution evenly in an on/off pattern.
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I'll assume it's because I'm running an almost-seven-year-old CRT which may or may not be on the fritz, and just leave it at that. :p
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I can see a clear difference between them on my laptop, but on the main PC their is no difference.
monitor thing.
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Throw your laptop to the garbage!
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They managed to interface with the visual nerve of a cat. They have his data, but not his interpretation.
Yeah, I'm not sure what this argument is about..
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it has nothing to do with that, this argument is about color.
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it has nothing to do with that, this argument is about color.
or the non-existance thereof
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It does exist. Just in our heads - basically it exists in-so-far as anything else we perceive does.
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Like shapes.
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WHAAAAAAT? (http://www.youtube.com/watch?v=nvz_3ddC-MA&feature=related) Okay I'd like an explanation of that one.
I'd say that things like color, sound, tastes, our sensations of hot and cold, etc exist only in our heads, but shapes? I'm pretty sure a spherical object is in fact spherical regardless of my perception of it. Or maybe I just don't understand what you mean by "shape".
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I think he's talking about image processing performed by our brain.
Off the top of my head, I remember that we do insanely good image segmentation. So good, that we sometimes (http://en.wikipedia.org/wiki/Illusory_contours) segment stuff that isn't supposed to be there.
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All well and good but unfortunately for Battuta colors definitely do exist.
On graphs.
And quarks.
:P
I remember reading some stuff about perception a while ago, it's amazing how little is directly representative of what actually exists.
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Quarks have flavor, too, proving that the scientist who came up with that nomenclature had a severe case of the munchies at the time. :p
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WHAAAAAAT? (http://www.youtube.com/watch?v=nvz_3ddC-MA&feature=related) Okay I'd like an explanation of that one.
I'd say that things like color, sound, tastes, our sensations of hot and cold, etc exist only in our heads, but shapes? I'm pretty sure a spherical object is in fact spherical regardless of my perception of it. Or maybe I just don't understand what you mean by "shape".
What do you mean an object is "in fact" spherical? Did you ask it, and it replied, "yeah, I'm spherical, congrats here are 10 points for your correct answer"? A sphere is an abstract shape, i.e., it is human made simplification, a mathematical caricature that we find useful to categorize stuff. You'll be in pains to actually find something that is in all its "reality" (whatever the hell that is) actually spherical.
The only "real" spheres I can remember are the ones that I define on AutoCAD. But that's tautological, you see.
I remember reading some stuff about perception a while ago, it's amazing how little is directly representative of what actually exists.
What you *really* mean is that some apparatus perceives "stuff" in a very different manner than your own eyes do, or that our own models of physics are not really entirely compatible with our own perception of the phenomena they describe. "What actually exists" is in the realm of transcendence.
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What do you mean an object is "in fact" spherical? Did you ask it, and it replied, "yeah, I'm spherical, congrats here are 10 points for your correct answer"?
Are all points on the surface of a non-rotating neutron star the same distance from the center (to a good approximation) only if something is observing it? Is there ever a time when it just decides to ignore the laws of physics and become angular? :lol:
I have an object that is approximately cubic in front of me too. See? Here it is!
(http://img84.imageshack.us/img84/6073/cuuuube.jpg)
Is it only in my head that this thing has approximately planar surfaces, each of the eight vertices a union of three orthogonal planes, each of the edges approximately the same length?
Topology is an empirical concept with deep roots in mathematics, and therefore I find it very difficult to agree with your claim that "shape" exists only in our heads, since you seem to have the same definition of shape as I do. That's like saying that math and physics suddenly breaks down if nobody's looking.
edit: I understand you're saying that there are no platonic solids in nature, simply because you can always find a deviation from perfection if you zoom in enough. And this I agree with. The event horizon of a solitary non-rotating black hole would probably be the closest thing to a perfect sphere in nature. But my point is that just as a perfect sphere is a mathematical entity, any random object has a topology that is also capable of being defined in the same way. One of the beauties of the principle of superposition is that any object can be represented by a sum of multiple equations. And that makes shape a concept that is not just an artifact of human perception.
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Agreed, shape is an objective property that can be mathematically defined. It does not require a cipher.
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Are all points on the surface of a non-rotating neutron star the same distance from the center (to a good approximation) only if something is observing it? Is there ever a time when it just decides to ignore the laws of physics and become angular? :lol:
Do objects follow the laws that our descendents wrote in a paper, otherwise they go to jail or smth? There is a lot of lack of rigor in our language, stemming from the fact that science "began" with a christian perspective that the universe obeyed the "laws of god", and it would be pretty cool for us to find such "laws", as if a celestial court existed that punished these and those particles if they dared disobey.
But I'm diggressing, flame me at will. Back to your point, no I'm not saying that things stop existing the moment you close your eyes. I'm saying that they don't care what you call them or what you decide they should do while calling it a "law". Is earth spherical, or not? Are the atoms of the surface (And what exactly constitutes the surface?) of the neutron star (and where is this "non-rotating" neutron star exactly located, apart from inside your own abstractions?) exactly placed in a spherical position?
No, you yourself agree they are not. They could as well be defined fractally, it depends upon what we want to study, to inform, etc.
I have an object that is approximately cubic in front of me too. See? Here it is!
[awkwardly intimate image of a cube trying to make a point]
Is it only in my head that this thing has approximately planar surfaces, each of the eight vertices a union of three orthogonal planes, each of the edges approximately the same length?
Read what I wrote. Abstract concepts that were invented by humans are very useful to categorize stuff that we see out there. I agree that if you choose to categorize your object as a "cube" then you are speaking english correctly and you are conveying useful information to me. ;)
Topology is an empirical concept with deep roots in mathematics, and therefore I find it very difficult to agree with your claim that "shape" exists only in our heads, since you seem to have the same definition of shape as I do. That's like saying that math and physics suddenly breaks down if nobody's looking.
edit: I understand you're saying that there are no platonic solids in nature, simply because you can always find a deviation from perfection if you zoom in enough. And this I agree with. The event horizon of a solitary non-rotating black hole would probably be the closest thing to a perfect sphere in nature. But my point is that just as a perfect sphere is a mathematical entity, any random object has a topology that is also capable of being defined in the same way. One of the beauties of the principle of superposition is that any object can be represented by a sum of multiple equations. And that makes shape a concept that is not just an artifact of human perception.
Topology is an abstract concept that has certain needs that you can't guarantee on your objects. I'm not saying that math and physics aren't useful. I'm saying they are constructs, they are not reality. They are models. Models do not "exist out there" as "objects".
This is an ancient mistake, like saying that things "exist in themselves".
I have a question for you. Does an orbit of a planet "really exists" outside the human mind?
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Agreed, shape is an objective property that can be mathematically defined. It does not require a cipher.
So you don't need mathematics to decypher it? What the hell are you talking about, you're not making any sense.
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Mathematics is an objective truth, not a construct. It is not a cipher with arbitrarily assigned meaning, like color.
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Mathematics is an objective truth, not a construct. It is not a cipher with arbitrarily assigned meaning, like color.
Said like a true religious! May the faith in the absolute absolve you from your uncertainties ;).
I will spare myself of the impossible mission to deconvert you from that kind of religious belief.
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Because mathematics is completely divorced from the empirical it is not constrained by the need for evidence. While mathematical axioms must be stated, altering the axioms simply leads to new mathematical approaches. No mathematical system will ever be complete, but mathematical constructs are objectively real in the way the charge on the electron is real - they are not constructs the way color is.
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While mathematical axioms must be stated, altering the axioms simply leads to new mathematical approaches. No mathematical system will ever be complete, but mathematical constructs are objectively real in the way the charge on the electron is real - they are not constructs the way color is.
But to establish what is objectively real one must prove it with axioms.
wikipedia.com/Infinite_regression
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Sure, but that's just philosophical fluffery. Color and shape (or other mathematical traits) are clearly on two different levels of existence; the latter could be easily derived even by an alien civilization with very different neural wiring. Math is for all intents and purposes objective common ground, and anyone who tries to argue that color is comparable is clearly Luis Dias.
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Its philosophical fluffery but it disproves the certainty of everything you've ever said :snipe:
Whats a cipher?
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No it doesn't, it demonstrates that mathematics is objectively available in exactly the way I've said all along.
A cipher is something like a language or, well, a cipher which cannot be determined from observation, it has to be transmitted along. An alien could not perceive color the way humans do without either examining a human brain or being given a description of how lights interact to produce color. On the other hand an alien can figure out what a sphere is without any help.
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No it doesn't, it demonstrates that mathematics is objectively available in exactly the way I've said all along.
State your axioms. Come on, all of them. And the axioms behind those axioms. We can do this all day...
The arguments not over till its over, and until you post an infinitely regressive explanation without getting banned for crashing the board the answer will remain uncertain.
A cipher is something like a language or, well, a cipher which cannot be determined from observation, it has to be transmitted along. An alien could not perceive color the way humans do without either examining a human brain or being given a description of how lights interact to produce color. On the other hand an alien can figure out what a sphere is without any help.
The alien would first have to share our concept space or a similar one to understand shapes no less than they would have to understand the brain and eyes to understand color. I'm not sure what definition of "color" you're using so I'm just going by neurology.
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Universe has patterns.
Humans observe the patterns and organize the data by giving them names.
End of story,
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No it doesn't, it demonstrates that mathematics is objectively available in exactly the way I've said all along.
State your axioms. Come on, all of them. And the axioms behind those axioms. We can do this all day...
They're not even necessary, the whole argument is 'what is in our head' vs. 'what could an alien come up with' and there is a clear difference between color and shapes there.
The alien would first have to share our concept space or a similar one no less than they would have to understand the brain and eyes to understand color. I'm not sure what definition of "color" you're using so I'm just going by neurology.
No it wouldn't, even the weirdest ****off alien is going to fall into one of two spaces:
1) has no concepts whatsoever
2) has a concept of 'all points at a fixed distance from a point'
There are a zillion ways to formulate the latter but mathematically they will all boil down to the same thing. You can't say the same about color, it cannot be derived without a human to explain it or a human brain to dissect.
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They're not even necessary, the whole argument is 'what is in our head' vs. 'what could an alien come up with' and there is a clear difference between color and shapes there.
Again, present the assumptions you use to justify that statement...
No it wouldn't, even the weirdest ****off alien is going to fall into one of two spaces:
1) has no concepts whatsoever
2) has a concept of 'all points at a fixed distance from a point'
There are several concepts an alien could understand such as points (or shucks, color) without understanding distance. Being able to picture all points at a fixed distance alone is not necessarily sufficient for understanding all but one dimensional "shapes".
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Again, present the assumptions you use to justify that statement...
It's an empirical argument, not a logical one. We know color only exists inside our head because you need a human head to make any sense out of it. The same can't be said of mathematics.
There are several concepts an alien could understand such as points (or shucks, color) without understanding distance. Being able to picture all points at a fixed distance alone is not necessarily sufficient for understanding all but one dimensional "shapes".
Man, the definition of a sphere is a mathematical concept and does not require any shared cipher to decrypt. I don't see how it can go any farther than that.
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It's an empirical argument, not a logical one. We know color only exists inside our head because you need a human head to make any sense out of it. The same can't be said of mathematics.
Okay dude but Im still waiting on those axioms.
Man, the definition of a sphere is a mathematical concept and does not require any shared cipher to decrypt. I don't see how it can go any farther than that.
Sure but color can be established as a mathematical concept as well through modeling of neurological processes.
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It can, but to do that you need to model something, which is the cipher.
Anyone who exists in the material world can derive the concept of a sphere. They don't need to find the Sphere Species and dissect their brains and model them.
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It can, but to do that you need to model something, which is the cipher.
It's possible to model hypothetical concepts which were not transmitted to you.
ed:
Anyone who exists in the material world can derive the concept of neurons firing in some way to create color. They don't need to find the Color Species and dissect their brains and model them.
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There's a clear difference between creating some hypothetical brain for no reason and the basic geometric concept of a sphere.
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No, there isn't fundamentally. Both are mathematical constructs. For all we know theres an alien race out there with a human brain equivalent model fetish.
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I cannot follow your logic in the slightest and it makes no sense to me. Generating a cipher is required to describe colors, it's not for spheres.
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By describing color I mean describing the physical processes that create the perception of color. Only mathematical logic is necessary to describe physics. Any consistent physical system can be described mathematically just as shapes can be.
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How would a three dimensional sphere appear to a being that observes non-three number of spatial dimensions
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It wouldn't appear worth ****, you would have to add to GBs list of characteristics all intelligent beings must have one of:
1 has no concepts whatsoever
2 has a concept of 'all points at a fixed distance from a point'
*3 has concepts other than that
ed: Distance is not the only way to represent what we perceive as space, potential energy can describe the same phenomena.
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How would a three dimensional sphere appear to a being that observes non-three number of spatial dimensions
How it appears is irrelevant. We can describe higher-dimensional shapes using mathematics even if we can't perceive them.
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In case you didnt get the QED on my last post:
1) By describing color I mean describing the physical processes that create the perception of color.
2) Only mathematical logic is necessary to describe physics.
3) Any consistent physical system can be described mathematically just as shapes can be.
or
1) Color is a physical process.
2) Math can describe physical processes.
3) Therefore math can describe color.
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I agree, it absolutely can, but there is no way that an alien species observing its environment would arrive at the human conception of color without
1) evolving the same visual system in parallel
2) deciding to **** around and simulate a bunch of visual systems
Whereas a sphere is mathematically basic and does not require the creation of an interpretive layer either by accident or design.
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An alien species would not arive at a conception of a sphere without
1) Evolving a similar spatial perception system in parallel
2) Deciding to **** around and invent geometry
A sphere is a geometric concept, everything in mathematics is derived from axioms, and math is not basic logic but 100% convention interpreted through langauge... I don't know what else to say.
Although yeah probabilitistically they're more likely to know what a sphere is there's nothing preventing them from knowing what color is too.
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I just don't see arriving at similar mathematical axioms as even in the same class of reasoning as simulating up the same visual system.
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You're prejudiced by the practical usefulness of studying the two topics. There are topics in any field which no one will even think of considering worth analyzing. Just because thinking about shapes is important to most people in order to sit in a chair or climb up stairs doesn't mean geometry wouldn't sound trivial and inane to some brain in a vat satisfied watching a bad monocolor screensaver all day. Nor might we rule out some alien be astounded we haven't discovered some mathematical concept they consider fundamental.
multiple edits, jumble of nonsense
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Because mathematics is completely divorced from the empirical it is not constrained by the need for evidence.
A sentence which is absolutely false. Mathematics is the tool of the empirical mind, and it started when someone started counting beans. Or potatoes. The details are somewhat unclear ;). Mathematics depends upon the empirical.
While mathematical axioms must be stated, altering the axioms simply leads to new mathematical approaches. No mathematical system will ever be complete, but mathematical constructs are objectively real in the way the charge on the electron is real - they are not constructs the way color is.
Exactly, this I can agree with. Mathematical constructs are as "real" as the charge of the electron. That is a nice proposition.
Anyone who exists in the material world can derive the concept of a sphere. They don't need to find the Sphere Species and dissect their brains and model them
This is an argument that states that the definition of sphere is much more simple than the definition of color. We can agree that this quantitative difference will translate to a qualitative one, because that distinction is useful for us humans with our little brains.
I agree, it absolutely can, but there is no way that an alien species observing its environment would arrive at the human conception of color without
1) evolving the same visual system in parallel
2) deciding to **** around and simulate a bunch of visual systems
Number 2 is clearly what is being discussed here, and it is true. You're arguing that spheres are "different" because they are easier. But mathematics doesn't stop being mathematics just because it is more complex.
But I wasn't even discussing "spheres" but "shapes". A shape is a perception of a figure that you see with your eyes. This perception is tainted by many things, for example how your eyes work the things that are around you into tridimensional shapes that you can platonically caricaturize, like say, a cube. An alien that could "see" the space between and within atoms, between the core and the electrons, etc., could well develop a completely different geometry. A sphere could be a really strange (but definable) geometry for it. Or it could be not.
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But I wasn't even discussing "spheres" but "shapes". A shape is a perception of a figure that you see with your eyes.
No it isn't.
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It isn't? Language barrier kickin in I see... so "shape" is already a geometrical construct, uh?
Well, geometrical constructs only exist in our brains, so the point stands !
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Because mathematics is completely divorced from the empirical it is not constrained by the need for evidence.
A sentence which is absolutely false. Mathematics is the tool of the empirical mind, and it started when someone started counting beans. Or potatoes. The details are somewhat unclear ;). Mathematics depends upon the empirical.
Five CPUs is empirical. the concept of "five" is abstract and completely removed from any empirical object. The only concievable way for an alien species not to have the concept of five is for them not to have the concept of discrete units.
But I wasn't even discussing "spheres" but "shapes". A shape is a perception of a figure that you see with your eyes.
No it isn't.
(http://www.blifaloo.com/images/illusions/phantom_shapes.gif)
whether triangles exist in this image is a matter of perception, but the concept of a triangle- and the concepts of vertices and edges- are simple mathematical constructs and most intelligent alien species that have developed mathematics could be reasonably expected to be familiar with this concept.
The human mechanism by which colors are perceived is not nearly as simple a concept- it would require at least an understanding or reasonable imitation of the human brain.
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Because mathematics is completely divorced from the empirical it is not constrained by the need for evidence.
A sentence which is absolutely false. Mathematics is the tool of the empirical mind, and it started when someone started counting beans. Or potatoes. The details are somewhat unclear ;). Mathematics depends upon the empirical.
Five CPUs is empirical. the concept of "five" is abstract and completely removed from any empirical object. The only concievable way for an alien species not to have the concept of five is for them not to have the concept of discrete units.
The concept of "five" couldn't ever have been produced by mankind if there weren't "five CPUs" to count. Or potatoes. That's the point. Thus you can never say that this concept is "completely removed", since this concept was firstly derived from the experience that there are "five" many different things, and that it would be interesting to create this abstract notion of numbers.
But I wasn't even discussing "spheres" but "shapes". A shape is a perception of a figure that you see with your eyes.
No it isn't.
(http://www.blifaloo.com/images/illusions/phantom_shapes.gif)
whether triangles exist in this image is a matter of perception, but the concept of a triangle- and the concepts of vertices and edges- are simple mathematical constructs and most intelligent alien species that have developed mathematics could be reasonably expected to be familiar with this concept.
I also think that it is highly probable for an intelligent alien species to have derived a similar definition, but this stems more from the fact that we share an apparently equal environment, with the same empirical opportunities we had before. I could not state the same certainty if such aliens were from a different type of universe with unknown laws and qualities.
The human mechanism by which colors are perceived is not nearly as simple a concept- it would require at least an understanding or reasonable imitation of the human brain.
...which doesn't invalidate my point. It would be harder to communicate the concept of colors, but it would be equally possible. It's just a degree of enough intelligence to do so. And we aren't a very bright species. Just enough to kickstart a civilization. Barely.
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So that entire post was basically a ringing concession that there is a serious difference between color and shape.
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hmm yeah. I was originally thinking about figures, or the perception of shapes we have in our brains.
For instance, what is the geometrical shape of the sun? It depends upon the wavelenght. Or what is the geometrical shape of a human being? Equal.
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Because mathematics is completely divorced from the empirical it is not constrained by the need for evidence.
A sentence which is absolutely false. Mathematics is the tool of the empirical mind, and it started when someone started counting beans. Or potatoes. The details are somewhat unclear ;). Mathematics depends upon the empirical.
Five CPUs is empirical. the concept of "five" is abstract and completely removed from any empirical object. The only concievable way for an alien species not to have the concept of five is for them not to have the concept of discrete units.
The concept of "five" couldn't ever have been produced by mankind if there weren't "five CPUs" to count. Or potatoes. That's the point. Thus you can never say that this concept is "completely removed", since this concept was firstly derived from the experience that there are "five" many different things, and that it would be interesting to create this abstract notion of numbers.
Any species that encounters two of the same type of object will likely develop a way to count them and thus a counting system. Is it conceivable that an intelligent species would never encounter two of the same object, including individuals of the species? The possibility is so remote that it is barely worth considering.
But I wasn't even discussing "spheres" but "shapes". A shape is a perception of a figure that you see with your eyes.
No it isn't.
(http://www.blifaloo.com/images/illusions/phantom_shapes.gif)
whether triangles exist in this image is a matter of perception, but the concept of a triangle- and the concepts of vertices and edges- are simple mathematical constructs and most intelligent alien species that have developed mathematics could be reasonably expected to be familiar with this concept.
I also think that it is highly probable for an intelligent alien species to have derived a similar definition, but this stems more from the fact that we share an apparently equal environment, with the same empirical opportunities we had before. I could not state the same certainty if such aliens were from a different type of universe with unknown laws and qualities.
The human mechanism by which colors are perceived is not nearly as simple a concept- it would require at least an understanding or reasonable imitation of the human brain.
...which doesn't invalidate my point. It would be harder to communicate the concept of colors, but it would be equally possible. It's just a degree of enough intelligence to do so. And we aren't a very bright species. Just enough to kickstart a civilization. Barely.
This isn't about communicating the concept; the idea of color would not be very difficult to communicate and would not even require a full model of the human brain, just a few facts about how the eyes and brain work. This is about the ideas developing by themselves, that is, being external to humanity and able to be experienced by another species without our intervention.
edit how does the geometrical shape of the sun depend on any wavelength
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Dammit, I lost 6 pages of interesting discussion.
You guys are having a discussion on visual system and nobody invited me?
Anyways, to beat a dead horse, what Herra Tohtori said a couple of pages ago:
I still maintain my view that colour is primarily a function of wavelength of photons and the spectral spread of the light arriving to the retina.
This is not enough to describe color sensation.
Also, my understanding is that the retina itself does some amount of preprocessing of the visual data, but can't exactly recall what it was. I need to dig up more of this on tomorrow at work. Would you recall something on this MP-Ryan? At this moment I'm not sure at which point even the residual distortion of the image is removed, I would guess it is visual cortex but then again, visual sensory stuff is outside my area of research (though I do instruments for that purpose too).
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Are all points on the surface of a non-rotating neutron star the same distance from the center (to a good approximation) only if something is observing it? Is there ever a time when it just decides to ignore the laws of physics and become angular? :lol:
Do objects follow the laws that our descendents wrote in a paper, otherwise they go to jail or smth?
I assert that the laws of physics as we know them do not suddenly cease to apply if nobody is looking. I like your "break the laws of physics --> go to space jail" idea though. Maybe that's what black holes are. :P
But I'm diggressing, flame me at will.
No thanks, I'm here for rational discussion. :)
Back to your point, no I'm not saying that things stop existing the moment you close your eyes. I'm saying that they don't care what you call them or what you decide they should do while calling it a "law". Is earth spherical, or not? Are the atoms of the surface (And what exactly constitutes the surface?) of the neutron star (and where is this "non-rotating" neutron star exactly located, apart from inside your own abstractions?) exactly placed in a spherical position?
No, you yourself agree they are not. They could as well be defined fractally, it depends upon what we want to study, to inform, etc.
I think you have missed the parts of my posts (both of them) where I said "to a good approximation" or words along those lines. "To good approximation" can also be quantified. I can state that an object's surface deviates from a perfect sphere by less than 0.1% and I would be making a statement that is based on reality, not perception.
I agreed with you that perfect spheres do not exist in the real world because there are always irregularities at small scales. That's why I gave the event horizon example, since that's the closest thing to a perfect sphere you'll ever be likely to find in nature.
Abstract concepts that were invented by humans are very useful to categorize stuff that we see out there. I agree that if you choose to categorize your object as a "cube" then you are speaking english correctly and you are conveying useful information to me. ;)
Concepts invented by humans and useful to categorize, yes, but they are still saying something accurate about objective reality. My cube is in fact a cube to within whatever error bars are required?
Topology is an abstract concept that has certain needs that you can't guarantee on your objects.
You can't guarantee that the surface of the gravity B probe's gyroscopes differ from perfect spheres by less than 50 atoms of thickness?
I'm not saying that math and physics aren't useful. I'm saying they are constructs, they are not reality. They are models. Models do not "exist out there" as "objects".
This is an ancient mistake, like saying that things "exist in themselves".
-Concepts like "length" and "orthogonality" are not models, they are mathematical truths.
-Nobody is saying that perfect shapes exist in nature.
-I am saying that surfaces/boundaries of objects are quantifiable and that said quantification is a statement about objective reality, something that is true with or without human presence.
I have a question for you. Does an orbit of a planet "really exists" outside the human mind?
The trajectory of an object through space over a time interval is not the same as the boundary of an object, so I'm afraid I don't see the relevance of your question. I'd say it "really exists" only as much as world-lines in 4D space-time "really exist".
Counter-question: Is it an empirical truth that Venus' orbit around the sun traces out a path that differs from a perfect circle by less than 1%? Or is that subjective, up for interpretation?
(Venus' orbital eccentricity is currently ~0.0067)
edit: [awkwardly intimate image of a cube trying to make a point]
hey look, he called it a cube! my work here is done. :P
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I think you have missed the parts of my posts (both of them) where I said "to a good approximation" or words along those lines. "To good approximation" can also be quantified. I can state that an object's surface deviates from a perfect sphere by less than 0.1% and I would be making a statement that is based on reality, not perception.
Yes, but it isn't reality. It is your own model. Atoms that are aligned gravitationally within an apparent sphere do not care what you call them.
I agreed with you that perfect spheres do not exist in the real world because there are always irregularities at small scales. That's why I gave the event horizon example, since that's the closest thing to a perfect sphere you'll ever be likely to find in nature.
It may be the "closest", but it is far from "perfect". They apparently have hairs, and if they rotate (which is pretty much a guarantee), then you lose the perfection of the sphere right there.
Spheres are platonic ideals. Reality is not ideal, it is for real, ar ar ar.
Concepts invented by humans and useful to categorize, yes, but they are still saying something accurate about objective reality. My cube is in fact a cube to within whatever error bars are required?
"Error bars" and "accurate" are also human concepts ;). They can also mislead you severely, and they themselves are prone to human point of view. There is no absolute truths, and that's not an absolute truth either ;).
You can't guarantee that the surface of the gravity B probe's gyroscopes differ from perfect spheres by less than 50 atoms of thickness?
For your purposes? Sure you can. You just can't say that it what it *is* happening in real reality, for that may or may not be the case. Something may have happened while you weren't looking, etc. ;).
-Concepts like "length" and "orthogonality" are not models, they are mathematical truths.
Mathematical truths are nothing more than useful human-made tautologies.
-Nobody is saying that perfect shapes exist in nature.
Therefore, "shapes" do not exist in nature, but they are useful for us to categorize what we see into different columns in tables ;).
-I am saying that surfaces/boundaries of objects are quantifiable and that said quantification is a statement about objective reality, something that is true with or without human presence.
How can something be quantified without a sentient being making the quantification? I'd guess that the audience is smart enough to realise that even quantum mechanics is a theory about what is seen by an observer, and what kind of predictions we can calculate between observations. Physics is not about what happens in "real reality", but about observational predictions.
The trajectory of an object through space over a time interval is not the same as the boundary of an object, so I'm afraid I don't see the relevance of your question. I'd say it "really exists" only as much as world-lines in 4D space-time "really exist".
The boundary of an object depends upon the interested point of view. Is the boundary of venus its upper atmosphere, or its ground? Is the boundary of the sun its convective layer or its corona? Or is it its solar system? Is it its solar wind bubble? It depends of what we are interested in.
Counter-question: Is it an empirical truth that Venus' orbit around the sun traces out a path that differs from a perfect circle by less than 1%? Or is that subjective, up for interpretation?
(Venus' orbital eccentricity is currently ~0.0067)
It is an empirical truth that it is so, currently. You use the word empirical correctly ;).
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Math is probably the only damn thing in the world that can be said to exist with absolute objectivity, 'out there'. It holds across species and even across conceivable universes. It's probably the very foundation of not just reality but all possible realities.
It's also immaterial to the topic at hand. I cannot conceive of a way in which a species would fail to mathematically describe the event horizon of a black hole. All species which encounter a black hole and describe its event horizon will do so using the same mathematics. The same cannot be said of the human perception of color. They are intrinsically different.
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I think you have missed the parts of my posts (both of them) where I said "to a good approximation" or words along those lines. "To good approximation" can also be quantified. I can state that an object's surface deviates from a perfect sphere by less than 0.1% and I would be making a statement that is based on reality, not perception.
Yes, but it isn't reality. It is your own model. Atoms that are aligned gravitationally within an apparent sphere do not care what you call them.
No, the arrangement of the atoms is reality. The statement that the geometry of the surface deviates from a perfect sphere by less than 0.1% is a statement about that reality. Maybe that is our disagreement afterall... I consider the description of that arrangement to be a shape, and you don't because you only consider "pure" shapes to be shapes, which obviously no material entity in nature will ever match. If that's the case then it's mainly just a difference of definition.
I agreed with you that perfect spheres do not exist in the real world because there are always irregularities at small scales. That's why I gave the event horizon example, since that's the closest thing to a perfect sphere you'll ever be likely to find in nature.
It may be the "closest", but it is far from "perfect". They apparently have hairs, and if they rotate (which is pretty much a guarantee), then you lose the perfection of the sphere right there.
Spheres are platonic ideals. Reality is not ideal, it is for real, ar ar ar.
I know all that already, and that's not the point. The shape of the black holes event horizon is the closest thing to a perfect sphere that you're likely to find in nature.
And I explicitly said "non-rotating" black hole in the first post, though actually on further reading it seems that rotation does not affect the sphericity of the event horizon. It only affects the ergosphere. That's not really relevant though because I already know and said that there are no perfect spheres in nature.
Concepts invented by humans and useful to categorize, yes, but they are still saying something accurate about objective reality. My cube is in fact a cube to within whatever error bars are required?
"Error bars" and "accurate" are also human concepts ;). They can also mislead you severely, and they themselves are prone to human point of view. There is no absolute truths, and that's not an absolute truth either ;).
Does that mean that my cube, in 'real reality', might be closer to a perfect sphere than a perfect cube because our human perspectives and error bars are misleading?
Topology is an abstract concept that has certain needs that you can't guarantee on your objects.
You can't guarantee that the surface of the gravity B probe's gyroscopes differ from perfect spheres by less than 50 atoms of thickness?
For your purposes? Sure you can.
No, I do not mean just for my purposes. I mean in objective reality. Is it within 50 atoms of thickness of a perfect sphere, or not?
You just can't say that it what it *is* happening in real reality, for that may or may not be the case. Something may have happened while you weren't looking, etc. ;).
Do you believe giant pink elephants suddenly appear on the moon in 'real reality' when nobody is looking?
I am saying that surfaces/boundaries of objects are quantifiable and that said quantification is a statement about objective reality, something that is true with or without human presence.
How can something be quantified without a sentient being making the quantification?
Sorry, my writing wasn't very clear. I mean that the surface of an object is what it is, with or without the presence of a sentient being. All intelligent sentient beings (assuming of equal or greater dimension to the object in question) can examine the object and quantify the geometry of the surface. Some might have more numerical accuracy than others, like one might say "I can tell that this is spherical to within 1%, while another might have better precision and be able to say "this is spherical to within 0.1%", but all of them agree, and all of them are statements about an objective reality -- the geometry (shape) of the object's surface.
Are we able to agree on at least this much?
Counter-question: Is it an empirical truth that Venus' orbit around the sun traces out a path that differs from a perfect circle by less than 1%? Or is that subjective, up for interpretation?
(Venus' orbital eccentricity is currently ~0.0067)
It is an empirical truth that it is so, currently. You use the word empirical correctly ;).
Excellent. Now say humanity never took an interest in astronomy and we never bothered to determine the orbit of Venus. Would Venus' orbit then be different from that ellipse with e~0.0067?
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Math is probably the only damn thing in the world that can be said to exist with absolute objectivity, 'out there'. It holds across species and even across conceivable universes. It's probably the very foundation of not just reality but all possible realities.
I'm sure you are about to make a proof of this idiocy.
It's also immaterial to the topic at hand. I cannot conceive of a way in which a species would fail to mathematically describe the event horizon of a black hole. All species which encounter a black hole and describe its event horizon will do so using the same mathematics. The same cannot be said of the human perception of color. They are intrinsically different.
So the absoluteliness of mathematics is dependent upon the limitations of your imagination? And that's enough for someone to state absolutes? Pretty pathetic.
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No, the arrangement of the atoms is reality. The statement that the geometry of the surface deviates from a perfect sphere by less than 0.1% is a statement about that reality. Maybe that is our disagreement afterall... I consider the description of that arrangement to be a shape, and you don't because you only consider "pure" shapes to be shapes, which obviously no material entity in nature will ever match. If that's the case then it's mainly just a difference of definition.
An arrangement is a human abstraction that is completely analogous, if not synonimous with "shape". So you just substituted words there. "Arrangements" are as real as the Earth's orbit.
And I explicitly said "non-rotating" black hole in the first post
I know, but the issue is that you were almost saying that ideals exist in reality because if we consider an ideal non rotating black hole, then its shape is ideal. Ok, but then you are making a tautology of ideals, aren't you? I also know that you didn't go so far.
Does that mean that my cube, in 'real reality', might be closer to a perfect sphere than a perfect cube because our human perspectives and error bars are misleading?
I'm saying that you cannot say anything about "real reality" at all, and it doesn't matter at all. Stick with empiricism, which is what we do best. Empirical reality is what matters. "Real reality" is a metaphysical entity, where spheres could be cubes and you could just be under an astronomical misaprehension. Perhaps God is a prankster ;). You can't know these things.
No, I do not mean just for my purposes. I mean in objective reality. Is it within 50 atoms of thickness of a perfect sphere, or not?
I have no idea, nor do I have any slight interest in knowing these transcendent truths.
Do you believe giant pink elephants suddenly appear on the moon in 'real reality' when nobody is looking?
I believe you can't make a statement about it. Most people do anyway, and they get along fine, so it's not a big deal.
Sorry, my writing wasn't very clear. I mean that the surface of an object is what it is, with or without the presence of a sentient being.
Yeah, but there is no "surface" if there isn't the concept of "surface", which is impossible to exist without someone inventing it. Mathematics is a language. It doesn't exist if there are no speakers. Things are what they are and the text is the text is the text.
All intelligent sentient beings (assuming of equal or greater dimension to the object in question) can examine the object and quantify the geometry of the surface. Some might have more numerical accuracy than others, like one might say "I can tell that this is spherical to within 1%, while another might have better precision and be able to say "this is spherical to within 0.1%", but all of them agree, and all of them are statements about an objective reality -- the geometry (shape) of the object's surface.
Are we able to agree on at least this much?
We can agree that there is an astonishing agreement in our inter-subjective analysis of our models, and that such phenomena is almost a miracle and should be praised.
I won't agree that this is outside human minds. It isn't solipsistic either. Let me clarify a bit: this distinction between "objective" and "subjective" in the sense that there are "truths" that are either one or the other is completely abhorrent except if you are a dualist. A dualist will believe that abstractions like mathematics "really do exist" in its own plane of existence, more or less like Plato defined, slightly apart from the material world which is imperfect and dull and noisy and chaotic. A dualist will think that objects exist "apart" from their own "soul" because souls are immaterial, therefore the distinction is necessary.
Problem is that if you aren't a dualist, this distinction is neither necessary nor consistent. Your own mind is an object as well inside the universe.
Excellent. Now say humanity never took an interest in astronomy and we never bothered to determine the orbit of Venus. Would Venus' orbit then be different from that ellipse with e~0.0067?
This question is only possible because we have an interest in astronomy and are considering an alternative universe. But the conversation itself is taking place in our universe, giving rise to the apparent paradox. If there wasn't *ever* an interest in astronomy so that no one could have ever done such measurement, the sentence would be unscientific and probably untrue, given the odds. No rational person would trust such a sentence.
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It's also immaterial to the topic at hand. I cannot conceive of a way in which a species would fail to mathematically describe the event horizon of a black hole. All species which encounter a black hole and describe its event horizon will do so using the same mathematics. The same cannot be said of the human perception of color. They are intrinsically different.
All species which encounter a human brain and describe its physical processes will do so using the same mathematics. Its just a matter them being more likely to come across a black hole.
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That's fine and dandy but how is it relevant to the question of whether or not there is a difference between shape and color in terms of existing only in our heads?
Color only exists if you model a human brain. Shape exists as a fundamental element of mathematics, which is universal and objective. I'm not arguing that you can't describe color mathematically but it's clearly on an entirely different level from shape, one that requires the creation of a (more or less) arbitrary intermediary.
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Pray to math, for she is an impartial god. ;)
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Shape exists as a fundamental element of mathematics
It depends on what you mean by "fundamental" as one must first remove location, scale and rotational effects to recognize shape. Otherwise the visual reasoning (colliculus and other areas) and mathematical reasoning (intraparietal sulcus) parts of our brain would be redundant to have together.
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Pray to math, for she is an impartial god. ;)
Yeah, the faith is strong with that one. I'm sure he will square Godel's incompleteness theorem with that bull**** about maths being all perfect, all independent from us stupid humans, universal and just godlike insanely good.
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Mathematical ability was important to human survival when we were evolving. The humans that didn't have math-brains died out.
That's why the math we do is the math that works.
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ITT: Maths = secular religion
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I'm sure he will square Godel's incompleteness theorem with that bull**** about maths being all perfect, all independent from us stupid humans, universal and just godlike insanely good.
Watching people who don't understand Godel muck about with Godel is almost as good as watching English majors use quantum mechanics.
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I'm sure he will square Godel's incompleteness theorem with that bull**** about maths being all perfect, all independent from us stupid humans, universal and just godlike insanely good.
Watching people who don't understand Godel muck about with Godel is almost as good as watching English majors use quantum mechanics.
Project much?
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No one here is actually a physicist except Hera.
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No one here is actually a physicist except Hera.
That would be incorrect. There are several other physicists on this forum, including me.
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Then why do you never talk about physics in these stupid threads?
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Also, my understanding is that the retina itself does some amount of preprocessing of the visual data, but can't exactly recall what it was. I need to dig up more of this on tomorrow at work. Would you recall something on this MP-Ryan? At this moment I'm not sure at which point even the residual distortion of the image is removed, I would guess it is visual cortex but then again, visual sensory stuff is outside my area of research (though I do instruments for that purpose too).
I mentioned this a few pages back, and it was buried deep in an explanation. Basically, photoreceptors respond to a range of wavelengths along absorption curves. Areas of the retinae then map directly to discrete areas of the primary visual cortex. It's the overlapping absorption curves that produce pre-processing; different light inputs can cheat to create the same perception of light to the organism because the conditions have no evolutionary meaning. The brain cheats - we don't see light differences that are irrelevant to us because of the way photoreceptors operate. Photoreceptors also send lateral signals, and can perform lateral inhibition on their neighbors, depending on the sequence of firing and the number of the same type firing in a discrete visual field [the retina sends data to the brain via visual fields, rather than based on the firing on individual photoreceptors].
This is probably enormously confusing; this is where I'd recommend Googling it =) Actually, this is kind of a good read: http://serendip.brynmawr.edu/bb/latinhib.html
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Then why do you never talk about physics in these stupid threads?
But I do when I see something interesting. I just don't have the time Herra does. And there are some topics I wont touch.
I mentioned this a few pages back, and it was buried deep in an explanation. Basically, photoreceptors respond to a range of wavelengths along absorption curves. Areas of the retinae then map directly to discrete areas of the primary visual cortex. It's the overlapping absorption curves that produce pre-processing; different light inputs can cheat to create the same perception of light to the organism because the conditions have no evolutionary meaning. The brain cheats - we don't see light differences that are irrelevant to us because of the way photoreceptors operate. Photoreceptors also send lateral signals, and can perform lateral inhibition on their neighbors, depending on the sequence of firing and the number of the same type firing in a discrete visual field [the retina sends data to the brain via visual fields, rather than based on the firing on individual photoreceptors].
This is probably enormously confusing; this is where I'd recommend Googling it =) Actually, this is kind of a good read: http://serendip.brynmawr.edu/bb/latinhib.html
Ah. It makes actually perfect sense and is nicely condensed. I recall human is more sensitive in detecting horizontal movement against vertical movement, but if this distinction happens within the retina I'm not sure. Human vision seems to perform poorly when only detection of angular magnification is conserned; when an object enlarges at a noticeable rate, that is usually too late to avoid anything if caught unguard.
Another interesting thing happens with eyepieces with large fields of view. Zeiss once manufactured an eye-piece with an apparent field of view exceeding 120 degrees. In the testing phase, it turned out that this didn't work as well as thought. When observing large angles, eye swivels in the socket and then there will be a displacement between the exit pupil of the eye-piece and the pupil of the eye.