I think that in a TV screen there is a source of light radiation, right there in the screen, but in the case of glass, the source of light is further beyond the glass itself. So these two are quite different with respect to the "illusion of depth". — Metaphysician Undercover
If your claim is that the entire visual perception is created by the brain, without any influence from things external to the brain, then what's the point in discussing how the brain differentiates between one object and another, in any sense whatsoever? — Metaphysician Undercover
If all the objects are simply created by the brain, then there is no difference between the TV screen and the glass, because they are both simply creations of the brain. —
Nor is there any real difference between any object created by the brain, in the sense that these are all fictions. —
However, the brain might create such a difference, dictate that X is different than Y. But then any difference is just a difference because the brain determines it as a difference.
It is the brain which interprets all the different neuronal impulses and builds this experience of depth. — dukkha
So take colour for example, physicalists don't generally believe physical things actually 'look' yellow or red in the physical world (and our brain internally generates a representation of how the objects 'look' which for us are colour experiences. — dukkha
Personally, I just don't see images on the surface of glass windows. Maybe you see things that way. If you do, and it works for you, fine. — Bitter Crank
I don't think there is any one here who supposes that his brain is in direct contact with objects. — Bitter Crank
The brain has no direct contact with any object or the sensing of it (though the sense of smell is pretty close to direct contact). The brain isn't in direct contact with the world outside the skull.
The brain constructs a complex model of the world that accounts for things like windows, twigs that appear bent in the water but are not, and so on. The process of model building starts in infancy, and progresses throughout life. If the model is wrong, we may get hurt, embarrass ourselves, or damage something. Feedback tells us whether our model of the world is right or wrong.
The world seems real to me, though what it would actually look like if we were in direct mental contact with the world I do not know. Our senses are limited, and though we have experience to help, some things we can not sense. I can not hear the high pitches of a bat. Bats are silent, as far as I am concerned. Some people say they can hear them. —
I have here a lump of 24 caret gold, a ruby, a sapphire, and an emerald. the lump is yellow, the ruby is red, the sapphire blue, and the emerald is green. If these 4 objects have no color, how do they reflect light at a particular wave length? If sun light passes through the emerald, how do the molecules composed of 4 or 5 elements absorb and re-emit green light that lands on your retina and triggers neuronal impulses that your brain decides is green IF there is no color there to start with? — Bitter Crank
The brain constructs a complex model of the world — Bitter Crank
The world seems real to me, though what it would actually look like if we were in direct mental contact with the world I do not know. — Bitter Crank
I would also like to point out, as an aside, that people ought have no problem discussing the phenomenology of their visual experiences without getting caught up and bogged down by physical descriptions of light and of the physical explanation/description of how perception is generated. I think the only reason this has happened is you all subscribe to the physical description of visual perception while at the same time not grasping that it entails representionalism because you want it both ways - a physical account of perception, and the objects around you being the actual physical objects in the external world which you are directly seeing, much like the naive realist. — dukkha
If photons are absorbed, then they aren't seen, nor are they re-emitted as a new set of photons. Light sources emit photons, everything else either absorbs, reflects or bends, or has no effect on the path of light (It is transparent).According to what Bittercrank wrote though, it is not the same "lightwaves/photons" that touch the stick as which touch your eyes. The ones that leave the stick get absorbed into the water. Then the water releases new ones. If this is true, then this supports dukka's claim that what we are seeing is the water, not the stick. But the photons must also get absorbed into the air, and new ones released into your eyes, so really, you don't even see the water, you see the air. — Metaphysician Undercover
Your brain doesn't actually know how far the light travelled from an object to the retina. The retina is just presented with a 2D image on its surface. For a rod or cone one light wave is much the same as the other i.e. it does the same thing whether the light wave travelled 10 centimetres or 10km. The depth information, the distance the light wave travelled, is not included in the light wave. It doesn't carry that information with it and pass it on to the retina. Retinal cells just fire off in the same way regardless of how far the light travelled. It is the brain which interprets all the different neuronal impulses and builds this experience of depth. — dukkha
Things look red blue yellow etc. This is not because things in the external world actually look red blue etc, it's because internally representing the radiation the retinas fire off in response to *as a colour experience* is evolutionarily successful. — dukkha
Yes, in terms of the physical description/explanation of sensory perception, all visual experiences have the same *ontology* - all are generated/created by a physical brain. But we're not talking about the ontology of visual perception itself - we're talking about phenomenology, how things are presented to us. So to couch it in physicalist terms, when we have a visual experience of glass, has the physical brain created a depth experience similar to the way it creates depth in a television screen experience (but better, so much better that most of us are fooled by it), or has the physical brain created a depth experience which is phenomenologically similar to the depth experience it creates with the objects around our bodies, i.e. the depth experience is NOT illusory - when we see glass the brain has presented to us a visual perception as if the glass is not there/invisible (like air) and we are seeing the various objects beyond the glass at differing depths. — dukkha
Or put it like this, does it make a difference in terms of the visual phenomenology, when someone is driving a car with a windscreen or without one? Is the experience the same in both cases, as in the depth of our visual field does not terminate at the inner surface of the windscreen when the car has one, and the depth of your visual field - how far you can see ahead is not changed at all from having a windscreen and not having one. So when there's no windscreen we experience the depth of our visual field as extending all the way to the road beyond the car, and further onward. Is the extent of your visual field unaltered by a windscreen being fitted, so that you are still seeing the road and world ahead of the car, much like you were when there was no windscreen? — dukkha
We don't see water, nor sticks. We see light and our brains create a model of the world using this information in light and how it is either being absorbed, reflected or passing through transparent objects. — Harry Hindu
I'm not. Seeing is when you are using light as a source of information about the world. Hallucinating or dreaming is when you aren't using light as a source of information about the world.I think you misuse the word "see". According to common usage, we see objects. We do not see the light which reaches our eyes, that's not a conventional use of the word "see". — Metaphysician Undercover
It's not. Seeing is when you are using light as a source of information about the world. Hallucinating or dreaming is when you aren't using light as a source of information about the world. — Harry Hindu
If photons are absorbed, then they aren't seen, nor are they re-emitted as a new set of photons. — Harry Hindu
You don't know what the external physical world looks like... — dukkha
I think you misuse the word "see". According to common usage, we see objects. We do not see the light which reaches our eyes, that's not a conventional use of the word "see". — Metaphysician Undercover
I would argue that we don't see objects. We see shapes and colors, which are merely representations of objects. — Harry Hindu
So my strategy now is to show that the scientific view of perception entails representationalism — dukkha
How do hallucinations make use of light? When you claim to see a giant spider, where is this reflected light coming from that cause the brain to create an image of a giant spider?Clearly that's false. Hallucinating still makes use of light, it is a misuse perhaps, but we still see depite the fact that we are hallucinating as well. Classing dreaming and hallucinating together as opposed to seeing, is a dreadful classification, totally unacceptable. — Metaphysician Undercover
Me thinks you need a refresher course on the behavior of light:Nope. If you pour water onto a piece of blotting paper it is absorbed and then after a delay to reach saturation point it is re-emitted. The mechanism is not identical but this is exactly what happens in refraction of light. The photon is momentarily absorbed by a molecule and then re-emitted. It may emerge modified in wavelength or frequency but it is still the same photon. The delay this causes affects the speed of passage of a stream of photons from one surface of a medium to the other. It is an utterly different process from reflection which involves elastic collisions. — Barry Etheridge
If you want to think you are seeing the object, then think that. If you want to think you are seeing a representation of the object, then think that instead. The difference between the two is nothing but word choice. — andrewk
The OP looks to me like a reboot of the old 'indirect realism' argument, but just using different words.
If you want to think you are seeing the object, then think that. If you want to think you are seeing a representation of the object, then think that instead. The difference between the two is nothing but word choice. — andrewk
The depth of his visual field ends at the TV screen, he's not actually looking at the world beyond the windowless room. — dukkha
Actually, I'd say that the part I put in italics is wrong unless there's some reason to believe that what we're receiving on the TV screen isn't accurate. — Terrapin Station
How do hallucinations make use of light? When you claim to see a giant spider, where is this reflected light coming from that cause the brain to create an image of a giant spider? — Harry Hindu
If we don't see light, then explain how we don't see anything (except the color black) when the lights are out? — Harry Hindu
We are capable of hallucinating even when there are no lights, just as we can hear voices even when there are no sounds. When we are deprived of any sensory input for a length of time we begin to hallucinate and dreaming is simply hallucinating while sleeping. The images don't come from light. They come from our imagination and memories. — Harry Hindu
An image displayed on the pixels of a TV screen, does not contain the literal objects on the other side of the wall! — dukkha
I know what those words mean from a practical point of view, but from that viewpoint, other than the effects of refraction, there is no difference between what is seen through glass and what is seen without the glass there. — andrewk
You appear to be trying to make some sort of metaphysical distinction and I can't see that the distinction boils down to anything more than word choice. — andrewk
Surely you don't think that when you look in a mirror, you are *literally* seeing your own face, as if the mirror magically turns the direction of your gaze back towards you? — dukkha
Or even just look through your windscreen, and then stick your head out your window and look at the road directly. They don't look exactly the same, in fact there's quite a few difference go check for yourself. How do you explain this if in both cases you're seeing the same road, if the windscreen is 'see-through'? — dukkha
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