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 I'm looking at the wall, and hallucinating a giant spider on the wall, I am still seeing the wall, and making use of light to see the wall.

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


Black is not a colour, so it is not the case that we see black, we see nothing. But seeing nothing, when there is an absence of light doesn't mean that we see light. What is the case is that we see objects, but we only see them if they are lit up with light. A laser could shine through the air in front of your eyes, and so long as air is perfectly clear, you wouldn't see it. If you look at the source of the laser light, you see it.

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


I know, but in these cases we aren't seeing, nor are we hearing. You don't see while you're dreaming, nor are you hearing when you imagine sounds. — Metaphysician Undercover

Your response is just plain ignorance.

This thread is about whether what's seen 'through' the glass are the very same objects that would be seen if the pane was removed. — dukkha

You can prove that with a Mach-Zehnder interferometer.

Would you say ulexite is 'see-through'?



Are you looking 'through' the rock at the page behind? Or at an image on the surface?





Are you looking through the ulexite at the paper behind, or at an image on the surface?



Are you looking through the ulexite at the pencil behind, or at an image on the surface of the rock?



Notice how the lines don't match up perfectly. Same sort of thing is taking place when you wind down your drivers side window half way, and notice that your wing mirror seen through the open window doesn't perfectly line up the lower half of the wing mirror seen 'through' the window.


'See-through'? Or an image on the surface?


As the image on the surface becomes clearer, the illusion that the rock is 'see-through' improves. Glass displays a very clear image, and so the resulting illusion is quite compelling. Nearly everyone falls for it.

A magnified image displayed on the surface. You don't look 'through' a magnifying glass.



Large image displayed on surface of rock pool. You are not seeing 'into' the water.



Only the head of the koi out of water is being seen. The rest of the koi is an image on the surface of the pond.



One of the finest examples of this sort of illusion. Images of the world beyond on the surface of the windows, and the actual world beyond seen through the middle.



Mirrors function using the same sort of illusion, but instead display an image on their surface of the world in front of them rather than the world beyond. The idea that when you look at a mirror it's like a portal for your gaze and shoots it back at the world behind you is clearly absurd.



Another example of the mirror illusion, what you are seeing is an image of the world/above in front (rather than below the surface) displayed on the surface of the puddle. Note how the ripples on the surface distort the image.



Refracted half of man is an image displayed on the surface of the glass.



The classic. Only the top part of the pencil above the lip of the glass is what's being seen. Everything below is an image displayed on the outer surface of the cup.



Still think the glass is 'see-through'? If you're looking through the glass at the spoon within, why is the spoon separated and facing the wrong way?

This is a very silly argument because light passes through glass just as it does through air or water. You say instead that there is an images projected on the surface of the glass. But our eye is not in physical contact with that surface, — John

Our eye is not in 'physical contact' with ulexite either, and yet there's an image displayed on the surface. In the youtube video above, the light travels from the card, through the ulexite, and then from the surface of the ulexite/TV rock through the air and is directed onto your retina by the lens of your eye. Some unexplained thing happens here and then we perceive the image of the playing card/toucan on the surface of the ulexite out in the world.

So, if it happens in the case of ulexite, why is it so "silly" to suggest the same process happens in the case of glass?

I highly suspect that the people in this thread who are acting incredulous are just so utterly fooled by the illusion - having misinterpreted their perception of clear objects their entire lives - that the mere suggestion that one of their fundamental beliefs about the world (a lot of things are clear) may be wrong is too difficult to comprehend. They are stuck in their dogmatic ways, unwilling (or even worse, unable) to consider any other interpretation but their own, and lash out at anyone who suggests an alternative. A sort of defensive attack.

The crazy things is that everyone acting like I'm some sort of idiotic moron are in fact the ones not interpreting clear things incorrectly. *They're* the ones being fooled by the illusion and quite frankly the people taking this attitude towards this idea are just embarrassing themselves, at least in my eyes. It's kind of like a young earth creationist calling someone who believes in evolution a silly idiot because creationism is just SO obviously correct, I mean like how could you even be so dumb to consider an alternative?

I've yet to see anyone actually present a cohesive alternative to this theory. Spouting derision is not actually an argument!

Can anyone who doesn't believe in this theory please articulate their understanding of clear things?



Can this image *really* be explained by just saying "it's refraction"? For me, that's not a good enough explanation.

I highly suspect that the people in this thread who are acting incredulous are just so utterly fooled by the illusion - having misinterpreted their perception of clear objects their entire lives - that the mere suggestion that one of their fundamental beliefs about the world (a lot of things are clear) may be wrong is too difficult to comprehend. They are stuck in their dogmatic ways, unwilling (or even worse, unable) to consider any other interpretation but their own, and lash out at anyone who suggests an alternative. A sort of defensive attack. — dukkha

John was apparently pointing out the straw man that you're attacking. You keep ignoring that you are attacking a straw man. Probably because it's not as fun that way.

What strawman? I'm arguing against the idea that clear things are see-through. Again, this theory can be discussed without arguing over physical theories of light and perception. It's irrelevant, I'm arguing over what we see, not how we see.

I'm arguing against the idea that clear things are see-through. — dukkha

Right. And how are you defining "see-through" (also versus how you think that other people are defining "see-through")?

Right. And how are you defining "see-through" (also versus how you think that other people are defining "see-through")? — Terrapin Station

That it is the very same object which is being seen, window or not. It's the same road being seen whether a windscreen is fitted in ones car or not.

So if we take how the direct realist sees the wrold, which is that what he sees is how the world exists, and it IS the external world which is being seen (rather than say a representation). The direct realist sits in a car with no windscreen fitted and looks out at the road ahead in the external world. Someone then fits a windscreen. The direct realist thinks that it's the very same road in the external world which he is looking at through the windscreen. In both cases, (he believes) the same object is being seen.

That is what we mean by 'see-through'. It means we can see the same object which is behind whatever transparent thing is in the way (eg windscreen) which we would be seeing if the transparent thing were not there. The transparent object does not block how far we can see ahead, in the same way that a wall does.

This is what we mean by 'see-through'. Whatever is behind the transparent object is what's being seen. The same thing which we would be seeing were the transparent object not there.

That it is the very same object which is being seen, window or not. It's the same road being seen whether a windscreen is fitted in ones car or not. — dukkha

But for one, now you ARE talking about perception instead--you're talking about "what we're seeing" per se.

What I was asking for, rather, is basically a definition of what "see-through" means. Something "see-through" would be "see-through" even if you're not seeing an object through it, no? That is, imagine that we put a see-through object in a vacuum. Have the properties of the see-through object changed?

What I was asking for, rather, is basically a definition of what "see-through" means. — Terrapin Station

That's what I gave: "This is what we mean by 'see-through'. Whatever is behind the transparent object is what's being seen. The same thing which we would be seeing were the transparent object not there."

Something "see-through" would be "see-through" even if you're not seeing an object through it, no? That is, imagine that we put a see-through object in a vacuum. Have the properties of the see-through object changed? —

I don't know what you're getting at. We would say the object has the property of transparency. If you're a physicalist (who doesn't understand the illusion) you would say that transparent objects are 'see-through'. And that transparent objects continue to have the property of transparency when nobody is looking 'through' them.

"Transparency" is a physical description of an object. It describes the property the object has, of allowing light to travel through the object.

"See-through" is an intuitive description of the way we perceive transparent objects. We think that when we look at transparent objects, we can see the objects which are behind the transparent object. We (not me) think of physically transparent objects as being 'see-through'. Intuitively it seems as though that is the case, that we are seeing through the object. But we are not.

My argument is that our intuition that we can see the objects behind a physically transparent object is wrong.

You got to part of what I was trying to ferret out there inadvertently: you're not using "see-through" and "transparent" as synonyms. I'd say that most people use them as synonyms. I do, too. With the way you're using "see-through," though, you're necessarily going to be talking about perception, because in your view, "'See-through' is an intuitive description of the way we perceive transparent objects."

Re what I was getting at about straw men, what is the difference, in your view, between "allowing light to travel through the object" and "having a property that enables seeing the object behind the transparent object"? Or in other words, how do you believe that most folks believe that "having a property that enables seeing the object behind the transparent object" works? Do you believe that they believe something other than "the property is simply allowing light to travel through the object"?

Re what I was getting at about straw men, what is the difference, in your view, between "allowing light to travel through the object" and "having a property that enables seeing the object behind the transparent object"? — Terrapin Station

It doesn't really matter though. Whether glass is see-through or not is not dependent on the amount of people who treat "transparency" as a synonym of "see-through".

You seem to think that "allowing light to travel through the object" is synonymous with "being able to see the objects behind the physically transparent object".

Or in other words, how do you believe that most folks believe that "having a property that enables seeing the object behind the transparent object" works? Do you believe that they believe something other than "the property is simply allowing light to travel through the object"? —

I'm not even sure most people have a theory about how it is that objects are "see-through". I'm pretty sure they just see glass, and believe they're seeing the objects behind the glass. I suppose if pressed a lot would say something about physical light.

"Allowing light to pass through the object" is a physical description of an objects property (transparency).

"Being able to see the objects behind the physically transparent object" is a description of ones visual experience.

They're two different *kinds* of description, which belong in two separate domains (physics, and phenomenology). You appear to be conflating the two and muddling then up. It doesn't matter that the majority of people also do this as well. Whether you can see the objects behind glass or not, is not determined by how many people think they can.

Ulexite/TV rock for example, is physically transparent (light can travel through the object) and yet it is not 'see-through'.

I don't know what you mean by "an image projected on the surface". My understanding is that, according to the physical understanding of seeing ( which is basically all we have to work with) there is no image projected anywhere, but rather light reflected off objects passes through the medium of air, any other transparent medium, or even a vacuum, and then passes through the transparent surface of the eye to fall upon the retina; where it stimulates rods and cones, and electro-chemical nerve impulses are then produced which travel via the optic nerve to stimulate the visual cortex, which produces the experience of seeing anything.

I don't know what you mean by "an image projected on the surface". My understanding is that, according to the physical understanding of seeing ( which is basically all we have to work with) there is no image projected anywhere, but rather light reflected off objects passes through the medium of air, any other transparent medium, or even a vacuum, and then passes through the transparent surface of the eye to fall upon the retina; where it stimulates rods and cones, and electro-chemical nerve impulses are then produced which travel via the optic nerve to stimulate the visual cortex, which produces the experience of seeing anything. — John

Would you agree that this would entail indirect realism/representationalism? As in, the visual cortex internally generates a visual field experience, with this visual field being within the brain, and therefore what we see is not the physical world directly, but rather an internal representation/model of the physical world. The brain takes in data from the physical world through the various sense organs (whose job is to convert physical phenomena - light waves, sound waves, etc, into neuronal impulses), collates and processes this data into an internal experiential model (with the model being all we directly have access to) of the world beyond it. Do you agree with this?

If so, then we can discuss 'images displayed on the surfaces of clear objects' because it is not actually the physical objects which we see around us. What we see are internally produced (by a physical brain) experiential representations (note the representations don't have to be accurate, as if our visual field is just a smaller scale version of how the physical world exists - all the representations need be is evolutionarily successful, point being that because we see an image displayed on the surface of glass does not actually mean there's an image on the physical glass in the external physical world). Because we are not actually directly in contact with the physical world, what's seen are internally generated representations/a model/internal approximation. So we can discuss images on the surfaces of clear things without debating how this is *physically possible*, without arguing over the mechanism by which the image is displayed, because what we are seeing is NOT a physical object. It's internal, experiential, and produced by a physical brain.

Do you see the point? This physical theory of perception entails indirect realism/representationalism. What we see is not actually the physical world, and how the physical world exists. The brain can internally model images on the surfaces of clear objects. The image we see on clear objects, is not an actual image on a physical object in the external world - it's an internally produced experience. Really, it can internally model the world however it wants. You could say the same thing about colours - the physical understanding is that there is no colours in the physical world, things don't actually look green or red or etc. Colour is an internal experience produced by the brain as a way of representing different wavelengths of radiation in the physical world. In the physical world, all light is is wavelengths of radiation. Our retinas respond to only a small range of the lengths of radiation, firing neuronal impulses only in response to radiation in that range. It internally produces using the data collated from all these various neuronal impulses firing off an experience of colour - the quales of red, blue, green, etc. So the point is that the brain can internally produce an experience of an image on the surface of glass, even though there may not be one in the physical world, in much the same way as it can internally produce colour experiences, even though things don't look red,blue,yellow in the physical world.

We can ask the question like this - how does the physical brain internally represent/model physically transparent objects which exist outside itself in the external physical world? To take a pane of glass for example, I say that the physical brain internal models glass to itself as if the depth of ones visual field does not extend beyond the surface of the pane. So what I mean is that if you remove the pane, the depth of your visual field, phenomenologically, extends out all the way into the surface of whatever objects are behind the pane of glass. Note here that we are not discussing the depth of the physical world or anything like that - because our entire visual field is an internal representation. When we remove the pane, the depth of our visual field - how far it is from our faces to the things (which aren't the physical things, they are internal representations of those things) that we are seeing extends/gets bigger/longer. The distance between our eye and the object it terminates at/extends to, goes from extending merely to the surface of the pane of glass, to the objects which are behind the surface, when the pane of glass is removed. When the pane of glass is refitted, the depth of our visual field becomes shorter, going from extending from all the way out onto the surface of the objects which are beyond the windowless window frame, to being reduced backwards and now only extending as far as the inner surface (the surface of the window facing your eyes) of the window pane.

Tell me if I'm not being clear btw.

So the illusion - the misinterpretation that people make when it comes to clear objects, is that they errenousoy believe the depth of their visual field extends further than it actually does. They think that their visual field extends all the way beyond the window pane and ends at the surface of the objects behind the pane, when in reality they are only seeing as far as the window pane. The reason they are making this interpretation, is because the image which is displayed in glass is extremely high definition and realistic, to the point that the vast majority of people (I've literally never heard of anyone else understanding glass like I do) mistake the objects in the image for actually being the objects behind the pane of glass. They think the depth/extent of their visual field is longer than it is.

If the question is then asked, "but how on earth does glass display an image? There's no pixels in glass like a TV screen, how does it do it? What's the mechanism?" the answer is that we are not actually the physical pane of glass in the external physical world. The pane of glass which we see does not contain within it any mechanism for producing the image displayed on its surface, because the pane of glass is already being produced by a mechanism (that is, physical neuronal processes through some mechanism produce internal visual experiences). The same mechanism which produces the window frame is the same that produces the image displayed on the surface of the window pane. Physical neuronal processes produce the experience of the window pane, and likewise produce the experience of the image on the surface of the glass. Nothing in the glass produces the image on its surface, because the window is itself an internal experience produced by a physical brain.

Do you get it?

I also want to say that I'm not actually a physicalist, I don't believe there is an actual physical world, I'm just explaining my theory here in this thread framing it under a physical theory of perception, because it seems people will be able to grasp it better that way. If you just say that a physical theory of perception does NOT entail representationalism, as in "light from physical objects travel to the retina which sends off neuronal impulses to the visual cortex AND THEN you are back out of your brain having direct access to the physical world", it would still not have any bearing on my theory because I'm not discussing the epistemology of our entire visual fields. As in, I'm not arguing about what we have access to ontologically with our vision (eg the physical world, internal representations, idealism). I'm discussing whether the things which are seen 'through' glass is actually an image on the surface, or are the objects beyond. Not whether the objects are physical or not.

I could make this same post but argue in terms of direct realism, so the direct realists find it easier to understand what I'm saying. But I shouldn't have to do either because this entire theory is about the experiential depth of our visual field (how far away the objects in glass are to us - are they on the surface, are do they appear to us to be beyond the pane). For the direct realist the image they are seeing would be on the surface of the glass in the external world (if the question is then asked "BUT HOW IS THAT POSSIBLE?" then I suggest the direct realist buys a piece of ulexite and sees for himself that images appearing on the surface of physically transparent objects (ulexite allows light waves to travel through it)) IS POSSIBLE AND DOES HAPPEN ALREADY. If they demand an explanation for how images appear on glass and water, then I demand if them an explanation for how images appear on ulexite. Nobody really knows how but the point is that it does happen and is possible.

For the direct realist the question is whether there's an image on the surface of glass in the physical world, or whether your gaze can penetrate through physically transparent objects and see what's behind directly.

For the indirect realist it's whether the brain internally models physically transparent objects as having images on their surfaces, or whether it internally models in its visual field the objects behind the clear thing so that clear things are internally modelled as "see-through". As in when the brain internally models depth, does the depth end at the surface of the glass or does it extend beyond the glass to objects behind it.

For the idealist it's much like the indirect realist but just drop the reference to the brain producing the visual experience. Does the depth of our visual field extend to the surface of glass/clear things, or do we see further, through clear things to the world behind/beyond.

Watch that video on ulexite, that's probably the best way to grasp my theory. Ulexite does present an image on its surface, it has fiber object properties, the light from behind can travel through it. The theory is that it's the same kind of thing happening with glass and other clear things, except the image is far clearer/high def, so clear in fact that the overwhelming majority of everyone ever does not recognise that it is an fact an image, they think what they are seeing is actually the things behind/beyond the surface.

But It can't be the things beyond, due to all the perceptual 'quirks' associated with clear things, which I have outlined all the images I linked above. We can't be seeing the actual spoon within a cup, for example, when the spoon we see is facing the wrong way is completely separated in two. It's an image if a spoon on the surface, the actual spoon is within the cup, and is not facing the wrong way and disjointed.

Agree now?

You write too much here to respond to in any detail. I would find it much easier if you would just focus on a couple of points, and succinctly state your arguments about those.

So, I'll just address a couple of your points. You ask whether I think the physical theory of perception I outlined entails indirect or representational realism. I don't see how it could. If we take the theory seriously then we are assuming that what we have observed and described are phenomena as they actually are. If what we have observed and described is not phenomena as they actually are then no cogent theory at all can be based on it. So, if we reject direct realism then we reject the possibility of any justifiable theory at all. We are just left with skepticism then.

So we can discuss images on the surfaces of clear things without debating how this is *physically possible*, without arguing over the mechanism by which the image is displayed, because what we are seeing is NOT a physical object. It's internal, experiential, and produced by a physical brain. — dukkha

If there is no coherent physical account of how images could be "on the surfaces of things" then I can see no sense in asserting it or even arguing against it. I don't know what you mean by saying that the things we see are not physical objects. They are physical objects by definition. You seem to be suggesting that we see brain images instead, but that notion is unintelligible, because if there are no physical objects then there is no physical brain either. Actually I would say there are no brain images, there are brain processes which are thought to accompany mental images, and I would say that mental images are not are not seen, they just are the seeing. This notion of separation in perception comes about by rationally hypostatizing how we talk about it, We will never be able to comprehensively get our heads around this in a way that will once and for all satisfy our analytic demands; and this fact just reflects the limitation of analysis itself.

If there is no coherent physical account of how images could be "on the surfaces of things" then I can see no sense in asserting it or even arguing against it. — John

I don't know what you mean by saying that the things we see are not physical objects. They are physical objects by definition. — John

You do realize hallucinations, illusions, and dreams exist, right? Do you also see there being no sense in asserting the existence of hallucinations? I assume not. So we have here a case in which we DO NOT have direct access to physical objects as they are, and yet we are perceiving something. What are we perceiving? We see things in our dreams which are not physical objects. We perceive all manner of illusions where there is no physical correspondence. There is no physical thing moving here, and yet we perceive movement:

You seem to be suggesting that we see brain images instead, but that notion is unintelligible, because if there are no physical objects then there is no physical brain either. — John

You don't seem to understand representationalism/indirect realism. Representationalists hold that both "brain images" and physical objects exist. They hold that what we have to access to are "brain images", which are internal representations of physical objects in the external world.

It would appear to me that you're suffering from a bad case of naive realism, and don't really have a basic grasp on the various theories of perception. The following article is a good introduction:

http://plato.stanford.edu/entries/perception-problem/

No, I understand all the arguments for indirect/representational realism, and I find them inadequate and even self-defeating
.
Firstly if all we know is representations of objects and not objects themselves then there is an unbridgeable gulf between the object and what is represented; the objects becomes infinitely distant from us. This leads to an inescapable radical skepticism.

Secondly, the scientific analysis of perception that indirect/representational realism is based upon must be assumed to give us accurate information about the physical world or else indirect realism cannot be, and indeed no theory at all can be, justifiably based upon it. That the analysis of perception does give us accurate information about the physical world and its objects relies on the assumption that we perceive the physical world and its objects as they are. We have direct access to the world, in other words, and this is direct realism. The scientific analysis of perception, if it is believed to be accurate, can support only direct realism; if it is not believed to be accurate it can support nothing.

Thirdly, the indirect realist claim that we do not have direct access to objects means that perception of objects is somehow distorted by the process of perception. But this unintelligible because it posits a real object which is completely unknown to us on the one side and our distorted representations of it on the other. But a real object conceived like this can be nothing at all to us. Conceived like this it is not the empirical object, but the noumenal 'object'. But to even speak of objects in the noumenal 'context' is incoherent, and is merely a logical convention. The function of the noumenal 'context' is rightly reserved as signifying the absolute mystery of being, not the unknowability of the empirical object.

You seem to think that "allowing light to travel through the object" is synonymous with "being able to see the objects behind the physically transparent object". — dukkha

If the lights were out, then could we see through the object? Does the quality that allows the object to interact with light the way it does, if light were in the environment, change when there is no light in the environment?

Firstly if all we know is representations of objects and not objects themselves then there is an unbridgeable gulf between the object and what is represented; the objects becomes infinitely distant from us. This leads to an inescapable radical skepticism. — John

This depends on what you mean by "know". Knowledge isn't the object, it is about the object. We know about objects by their representations. Knowledge itself is composed of sensory impressions.

Secondly, the scientific analysis of perception that indirect/representational realism is based upon must be assumed to give us accurate information about the physical world or else indirect realism cannot be, and indeed no theory at all can be, justifiably based upon it. That the analysis of perception does give us accurate information about the physical world and its objects relies on the assumption that we perceive the physical world and its objects as they are. We have direct access to the world, in other words, and this is direct realism. The scientific analysis of perception, if it is believed to be accurate, can support only direct realism; if it is not believed to be accurate it can support nothing. — John

You're missing something very important: Natural selection. Through the process of natural selection, more accurate interpretations of sensory impressions are favored over less accurate ones, which builds up exponentially to the detail and accuracy we humans experience with our sense of vision and other animals experience with their sense of hearing or smell.

On the contrary, you're missing the very important point; that is if we do not have direct (meaning undistorted) access to the physical world via perception, then the theories of evolution and natural selection fare no better than the scientific theory of perception; they would also be based on distortions.

Firstly if all we know is representations of objects and not objects themselves then there is an unbridgeable gulf between the object and what is represented; the objects becomes infinitely distant from us. This leads to an inescapable radical skepticism. — John

I agree, indirect realism logically collapses into idealism. Because the external/physical world for the indirect realist doesn't really have an explanatory value. You would be positing an entire 'level' of reality (mind independent world) in order to explain the existence of your conscious experience, but you can have no real knowledge of this mind-independent world because it's beyond what you can access. You can't even know that it causes your conscious experience, so there's no point positing it because it doesn't have any explanatory value. The indirect realist should just become an idealist and analyse the physical world as merely being a concept or idea in the indirect realists mind and has no actual existence.

People like Thomas Metzinger however do flesh out ("Being no-one: The self-model theory of subjectivity") the indirect realist theory, and give a physical, scientific account of our conscious experience under the theory of representationalism. He claims his theory can be tested scientifically and has predictive value.

Secondly, the scientific analysis of perception that indirect/representational realism is based upon must be assumed to give us accurate information about the physical world or else indirect realism cannot be, and indeed no theory at all can be, justifiably based upon it. That the analysis of perception does give us accurate information about the physical world and its objects relies on the assumption that we perceive the physical world and its objects as they are. We have direct access to the world, in other words, and this is direct realism. The scientific analysis of perception, if it is believed to be accurate, can support only direct realism; if it is not believed to be accurate it can support nothing. — John

The indirect realist believes/assumes his representations are accurate depictions of the external world. Your argument only works if you believe representations are not accurate.

Anyway, going back to the thread topic, for the direct realist (you), the question is whether in the external world glass displays an image on its surface, or one can directly perceive the objects behind it. You seemed to argue that because I have not given a physical account of how glass displays an image on it's surface, it therefore cannot be possible:

If there is no coherent physical account of how images could be "on the surfaces of things" then I can see no sense in asserting it or even arguing against it. I don't know what you mean by saying that the things we see are not physical objects. They are physical objects by definition. — John

Firstly, ulexite displays an image on its surface and this is uncontroversial. Do I need to present a physical account of what makes this happen before you believe that there's an image on the surface? Just go buy some ulexite and see for yourself. It's uncontroversial that some physical things can display an image on its surface. All I'm doing is extending this physical phenomena to include all transparent things.

Anyway, if we take what you've been saying - that we perceive objects in the external world, *as they are*, then there's a contradiction here because glass distorts and refracts the way in which see things. We don't see things through glass *as they are*. Fish seen under the surface of water, are not actually in that location due to refraction. So if you're perceiving the fish *as it is*, then how does this make sense because you're not seeing it in the right location. The fish can't be seen in one place, but actually be in another, and yet you are seeing the fish *as it exists in the external world*. Just look at all the illusions associated with clear objects I've posted on the previous page. Are we really seeing the world *as it is* directly when we see these illusions/distortions? Go to a hall of crazy mirrors, if you're seeing yourself *as you exist physically* then your head exists physically as a warped objected with a head the size of a beach ball and a pinched in nose, with wavy shaped arms, and also your body constantly drastically changes shape physically, from being super wide to super narrow to super tall and stretched to bunched up and tiny.

Again, your argument doesn't account for dreams, illusions, and hallucinations. We don't see physical objects in the external world *as they are* when we have these experiences. So what do we see? Some sort of mental construction, some percept/experience generated within the brain. The movement illusion I posted on the previous page is an example of this. There is no physical thing which is moving, and yet we perceive movement. Seeing as though there's no movement in the physical world and yet we are perceiving movement, the movement we see must be some sort of brain generated experience/perception. We are not seeing the world *as it is*.

So what I'm doing here is, fitting my theory into a direct realist account of perception. Either the image is on the surface of the glass, and we directly perceive it in the external world, or you see through glass at the object behind *as it exists* - and if this is so then the world seen through rose tinted glass must be physically pink. The man i posted in the swimming pool must therefore physically exist with his head completely separated from the rest of his body. If you take LSD and perceive the world warping and moving and covered in shifting geometric patters, is this how the world physically exists? No.

Not even direct realists hold that when we see illusions or hallucinations (or have dreams) we are seeing the world *as it exists*. This is the difficulty with naive/direct realism, in that it really struggles to account for these. The direct realist is in this position of asserting that only a very particular type of perception gains him direct access to how the world physically exists (obejects seen in the daytime, with clear lighting, while not being under the influence of drugs or have an sort of perceptual illness, including bad vision, and you can't be perceiving an illusion, mirage, hallucinating or seeing through clear things). What about the perceptions of animals, or even babies? They wouldn't perceive the world at all like we do. Why does the way you perceive the world give you direct access to how the world really exists outside yourself, but yet, how say a fish or dog or any other organism sees the world doesn't allow it to see the physical world as it exists? Why is your visual field a direct perception of the external world but the fishes not? And if the fish does not see the world as it is then what does it see? An internal representation? This is a very human centric view.

If the lights were out, then could we see through the object? Does the quality that allows the object to interact with light the way it does, if light were in the environment, change when there is no light in the environment? — Harry Hindu

I'm not quite sure what you mean. If I'm understanding the question right, I would say that no, it being dark does not allow you to 'see-through' the object at the world behind it. In both the cases of it being light or dark, you would still be seeing an image on the surface of the clear object. You would just be seeing a really dark image on the surface of the clear object.

When we dream, remember and so on we don't see anything, we imagine things.

The indirect realist believes/assumes his representations are accurate depictions of the external world. Your argument only works if you believe representations are not accurate. — dukkha

If the indirect realist believes that then their position is no different than the direct realist's who does not deny the veracity of the scientific model of perception. Also, I think the term 'representation' itself conveys a misrepresentation of the situation. Objects are presented to us in perception; not represented by it. Objects act on us so as to become present; and they cannot be present in any other way. If objects were represented by perception then it would follow that there must be originals that are being represented and this is an incoherent idea.

A representation of an object is a model of it created through conceptual analysis; and that is simply not what perception does.

No matter what we say it will not be the real situation, but only more or less coherent and consistent with our experience and linguistic usage, and hence more or less adequate.

You can fit your head into the cosmos, but you will go insane if you try to fit the cosmos into your head. ;)

On the contrary, you're missing the very important point; that is if we do not have direct (meaning undistorted) access to the physical world via perception, then the theories of evolution and natural selection fare no better than the scientific theory of perception; they would also be based on distortions. — John

You seem to think that distorted means completely and utterly inaccurate. I see accuracy in degrees, not a simply black and white, accurate and inaccurate. I simply point to the fact that you are alive right now as evidence that you know enough truths about the world to not just survive in it but to procreate, communicate, make predictions, travel about, find things you've lost. You can function in this world for a long period of time. Try doing that without any knowledge or knowledge so distorted that there is no correlation between what you experience and what is out there. I point to the fact that we can communicate and understand each other even though we have never met each other and have different backgrounds as evidence that we both hear and see very similar things and engender very similar meanings from these written symbols.

I'm not quite sure what you mean. If I'm understanding the question right, I would say that no, it being dark does not allow you to 'see-through' the object at the world behind it. In both the cases of it being light or dark, you would still be seeing an image on the surface of the clear object. You would just be seeing a really dark image on the surface of the clear object. — dukkha

Only if there was a limited amount of light could you see anything. I'm talking about utter darkness. No light at all. Have you ever hear of the phrase, "it's so dark I cant see the hand in front of my face"? I'm talking about that dark.

Why is it that you can't see anything, transparent or not, when there is NO light and why you see such vividness and detail when there is plenty of light? Why does the level of detail and vividness seem to correlate with the level of light in the environment?

I can't believe you've managed to keep this going this long so let's say you're right and see if it raises no problems. Assuming that you at least agree that the reason we see anything other than direct light sources is because light reflects off it and that light reflects at the angle of incidence, here's what must be happening in your scenario.



Light A reflects off the object and forms an image on the surface of the 'transparent' material. Light B reflects off the image and is seen by the eye. But this raises two paradoxes ...

Light A passes from outside the material to hit the object yet the reflected light A does not pass through the material to outside it but stops at the surface to form an image. How can this be? Either the surface stops light or it does not.

Light A reflects uniformly off the surface of the object to form the image on the surface. Light B reflects uniformly off the image to transmit the image to the eye. So what is the source of the distortion? There should be a perfect image of the object and the eye should see that image perfectly there being no source of interference in either light path.

There being no rational solution to these self-contradictions it cannot be the case that we are seeing an image on the surface of transparent or translucent materials. There being no such paradoxes in the usual explanation ...



... that reflected light travels through the surface of the water but on a diverted path I must suggest that, until a better explanation comes along, it is irrational to favour your own explanation.

You seem to think that "allowing light to travel through the object" is synonymous with "being able to see the objects behind the physically transparent object". — dukkha

As I phrased it in the post you're responding to, the second one should be (B2) "having a property that enables seeing the object behind the transparent object." That's different than (B1)"being able to see the objects behind the physically transparent object," because in (B2), the subject of the phrase is the object, not our perception, even though we're saying something about a property of the object relative to our perception, whereas with (B1) , the subject of the phrase is our perception.

It's my contention that (B2) is not only what's functionally going on with talk about transparency and "see-thoroughness," but that that's what people typically have in mind with "see-thoroughness." And thus it's my contention that arguing against anything else is arguing against a straw man.

I'm pretty sure they just see glass, and believe they're seeing the objects behind the glass. — dukkha

Yes, which is what I think, too, but what it is to see objects behind the glass is that light passes through the glass, and light waves/photons stimulate your eyes, etc. Again, suggesting that people typically think otherwise, including us naive realists, would amount to arguing against a straw man.

They're two different *kinds* of description, which belong in two separate domains (physics, and phenomenology). You appear to be conflating the two and muddling then up. — dukkha

When I talk about stuff like this, my intention isn't to follow the conventions of any discipline as a set of social practices. I'm a physicalist or "materialist," so I'm going to believe that there aren't separate domains in ontological terms.

I mentioned earlier that the Mach-Zehnder interferometer falsifies any idea that photons don't pass through transparent media.

It occurs to me that it takes a deranged zealot to claim that optical fibres don't transmit photons, particularly when used in ultra-secure quantum communication applications.