You seem to be wanting to make a point against what I have said, but I cannot for the life of me see what it is.

You seem to be wanting to make a point against what I have said, but I cannot for the life of me see what it is. — John

I thought I was quite clear, that is unless you are trying to act like you don't understand what I said in a feeble attempt to prove me wrong.

If you are correlating the level of accuracy to the directness or indirectness of our access to the world, then direct realism would have to account for our mistaken impressions that we often have. If direct access means ultimate accuracy and indirect access means ultimate inaccuracy, then it seems to me that the solution is somewhere in the middle because we experience both accuracy and inaccuracies in our interpretations of our experiences. In other words, as I said before, accuracy isn't black and white. We can be accurate much of the time but still make mistakes. This shows that we have some level of indirectness but not so much that we can't know anything about the world.

"Mistaken impressions" just means "mistaken ideas" not "mistaken perceptions"; when we see the bent stick, our seeing of it is exactly what you would expect given that the light reflected off the surface of the stick is refracted by passing from one medium to a different medium. Even when we know the stick is really straight we continue to see it as bent, but this is not a mistake; that is just how it should appear.

We can have wrong ideas about how things work; in fact none of our ideas about how things work are absolutely infallible. That is because our ideas about how things work are ideas of causation; that is ideas of forces which cannot be directly observed.

On the other hand we cannot have mistaken ideas about how the world appears. Everything we know tells us it mostly appears just as it should. It is true that our imaginations may sometimes be projected out into the world; but that is something else.

Your diagram is not correct because you forgot the refraction of the light caused by the water, and Light B continues to travel below the water, because water is physically transparent. Light A is the light which actually reaches the retina. I drew the diagram correctly here:



If the image is too small to read just click on this link: larger image of diagram above

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. — Barry Etheridge

No. Light A doesn't stop at the surface, it continues on and reaches the retina. We then see an image of the object which is on the surface of the water, but it appears at a depth below the water. A stereogram has the same sort of function - whereby what's seen *appears* to be at a depth beyond/below the surface of where the stereogram is printed/displayed on. That is, below the paper where the stereogram is printed on, or below the computer screen on which it is displayed, both of which are flat, 2D surfaces. The *appearance* of depth is just an illusion, you aren't actually seeing something which is behind the stereogram, you aren't seeing behind the paper or computer screen that the stereogram is displayed on. It merely appears that way to you. In reality what you are actually seeing is the surface of a flat object (eg paper or computer screen)).

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. — Barry Etheridge

In your diagram you forgot to draw the refraction caused by the water. Light A travels from it's source (eg the sun) to the surface of the water. Because water is physically transparent this means that Light A can travel through it (at a refracted angle). Light A, travelling at a refracted angle, reaches the object below the water and is reflected at a perpendicular angle up towards the surface of the water. The light then stops being refracted because it has reached the air, and so travels at a different angle towards the eye.

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 ... — Barry Etheridge

Well, yeah there is. We don't actually need to debate this now because it's a separate issue, but there is a paradox for the direct realist, of the eye needing to function in two completely different ways in order for direct realism to make sense. Those two ways being - the scientific biological function of the eye, and how the direct realist wants the eye to function as 'windows upon the world' which are being looked *through*.

If we look at the biology of the eye, all it does is focus, using the lens, incoming light upon the retinal cells. All retinal cells do is send off (essentially) an electrical charge in response to a light wave being detected. This electrical charge/signal travels through the optic cord and into the brain along a massive series of neurons, eventually reaching the visual cortex. The point being that there is no outgoing process here. Light travels to the retina, electrical charge travels into the brain. There is no means here by which one looks back out at the world. It doesn't make sense. The direct realist however thinks that our eyes are like 'windows upon the world' which we look 'through'. But this isn't supported by the biology of the eye. There is nothing which goes through the eye and back out into the world into the opposite direction towards which the light came in. Nothing goes back in that direction. And yet the direct realist understanding of vision assumes that is the case. The direct realist thinks when he looks at something, it's like an arrow travelling from his eye to the object in the world, as if his gaze goes from his eye to the object in the world and he sees that object in the world. But our scientific understanding of the eye (and the entire visual sensory system) does not support this at all. There is no outgoing process. Light travels to the retina, retina sends of an electrical charge into the brain. So through what means does your gaze travel back from the electrical charge in the brain, to the retina, out the lens of the eye, through the air and reaches the objects in the world? There is no biological means by which this could happen.

It doesn't make sense at all. Which is why in this thread I have repeatedly argued that the scientific/biological understanding of the visual sensory system entails *indirect* realism. Which would involve light in the physical world travelling to a retina, an electrical charge then travels from the retina into the brain towards the visual cortex. A visual perception is then generated by the visual cortex, which is what we visually experience. Our visual field would be located within a brain (because it's internally generated within a visual cortex), and what we see would not be the physical world directly, as if our eyes were windows upon the world, but what we see would be onboard (a brain) internal representations/model of this external physical world, located within the brain. The physical refraction of light occurs in the external physical world. What we see is an internal representation of this. So we couldn't point at a bent stick in water and say "that water *there* is refracting the lightwaves". Because all we are seeing is an internal (within a brain) representation of the physical refraction existing outside our brains in the external world. The physical refraction isn't happening in the water in the cup that we see, rather the physical refraction occurs in the physical external world outside the brain. We merely see an internal representation of this physical process.

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. — tom

Yawn...

I really don't know you're having such trouble with reading comprehension. I have *repeatedly* stated in this thread that physically transparent objects allow light to travel through them.

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

I have visual experiences in my dreams. But regardless we DO see hallucinations and illusions. You conveniently skipped over these.

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. — John

No, there's a huge difference between seeing a physical object directly, and seeing a representation/model of a physical object. It's the difference between a map and a territory. No matter how accurate a map is, it's still not the territory.

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. — John

You're just asserting this. Why is the "thing-in-itself", "noumena", "mind-independent object", an incoherent idea?

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

But you can fit a model/representation of the cosmos within your head. For the direct realist, a physical brain exists within an external noumenal reality. Physical neuronal processes within that brain generate/cause ("are equal to" if you're a type identity theorist) an experience of a phenomenal world, which is what the indirect realist has access to.

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. — Terrapin Station

You are arguing that when someone says an object is "transparent" or ''see-through'', what they mean is that the object has a property which enables seeing the objects behind the transparent object.

Ok, sure. But the point of this thread is that physically transparent objects don't actually have that property. People may think they do, but they don't.

[/quote]'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.[/quote]

Can you finish this ''etc'' and actually outline how it is you think visual perception works? Because I'm pretty sure all you're going to say is, ''light travels from a source towards the glass, the light then travels through the glass (at a refracted angle) to the other side and carries on towards the eye, the light then travels through the lens of the eye and is focused upon the retina, the retina responds to the light wave by producing and sending an electrical signal, a signal which then travels through the optic cord and into the brain along a massive series of neurons, eventually reaching the visual cortex, and then we see the object behind the glass in the physical world."

What's actually happening in the italics? Whereby we've traveled from processes within the visual cortex to way back out into the physical world beyond the brain. How does this happen? I argued earlier in this thread that there is no (known) biological mechanism by which this occurs, and so the physical account of perception entails indirect realism. As in, ''...electrical signal which travels through the optic cord into the brain, eventually reaching the visual cortex, which then creates/generates an internal (within the brain) visual representation of the glass in the external world. And this internal representation is what we perceive.

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. — Terrapin Station

Phenomenology is the philosophical study of the structures of experience and consciousness. It doesn't have any ontological commitments. What I meant by ''separate domains'' is two different disciplines, or areas of study. In the domain of physics, we study and describe light waves, mass, etc. In phenomenology we study (or really, analyse) our visual 'quales'. A physicalist should have no trouble practicing both disciplines. There's nothing contradictory about the two (well, unless you're an eliminative materialist!).

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? — Harry Hindu

What point are you getting at?

"Mistaken impressions" just means "mistaken ideas" not "mistaken perceptions"; when we see the bent stick, our seeing of it is exactly what you would expect given that the light reflected off the surface of the stick is refracted by passing from one medium to a different medium. Even when we know the stick is really straight we continue to see it as bent, but this is not a mistake; that is just how it should appear.

We can have wrong ideas about how things work; in fact none of our ideas about how things work are absolutely infallible. That is because our ideas about how things work are ideas of causation; that is ideas of forces which cannot be directly observed.

On the other hand we cannot have mistaken ideas about how the world appears. Everything we know tells us it mostly appears just as it should. It is true that our imaginations may sometimes be projected out into the world; but that is something else. — John

But the stick isn't bent, the light is. We don't see sticks in water. We see light. We are informed of sticks and glasses of water by the light that enters our eyes. When you see a bent stick, do you feel a bent stick also? How is it that two different senses give you different information? Because we are using two different means of obtaining information about the world - one by using the repulsive force of electromagnetic energy (touch), and the other by using the wavelength and angle of electromagnetic energy entering the eyes. Our sense of touch is more direct than our sense of vision because it doesn't use electromagnetic energy at a distance. Why would it be useful then to use reflected EM energy from a distance to inform us about the world? Because it is often useful to know about objects, especially dangerous ones, before they are right next to you and eating you.

We see objects indirectly. We see light directly, or at least more directly than the object. This is what I mean by directness and indirectness coming in degrees. Light itself isn't colorful. Color exists only as a representation of EM wavelength in the brain.

Also our visual experience provides a perspective - of the world located relative to the eyes, but the world isn't located relative to the eyes.

I'm pretty sure all you're going to say is, ''light travels from a source towards the glass, the light then travels through the glass (at a refracted angle) to the other side and carries on towards the eye, the light then travels through the lens of the eye and is focused upon the retina, the retina responds to the light wave by producing and sending an electrical signal, a signal which then travels through the optic cord and into the brain along a massive series of neurons, eventually reaching the visual cortex, and then we see the object behind the glass in the physical world."

What's actually happening in the italics? — dukkha

I don't understand why you're adding the part in italics. It's not "and then we see . . ." It's rather "the above description (more or less, just because we're not worrying about whether each of those details is correct--for example, your nervous system doesn't just work via electrical signals, it's electrochemical) is what seeing an object behind the glass is."

As in, ''...electrical signal which travels through the optic cord into the brain, eventually reaching the visual cortex, which then creates/generates an internal (within the brain) visual representation of the glass in the external world. And this internal representation is what we perceive.

In my opinion, which unfortunately I don't know how to relay here so that it doesn't come across as patronizing, you don't understand what naive realism is, especially in contradistinction to representationalism. I tried to explain this before, and I believe in this thread, but I don't know if anyone really read or commented on it.

Per your description immediately above, the difference occurs only with respect to the "creates a representation" part. The analogy that I use is that naive realists believe that the process is more or less like photography. Representationalists believe that the process is more or less like painting.

We agree on everything up to "reaches the visual cortex." Naive realists believe that information changing the state of the visual cortex IS perception/awareness of externals--there are no additional steps involved. The process is analogically like light entering a camera and creating an image on film.

Representationalists, however, believe that once the information reaches one's brain, there's another, unconscious process that occurs, whereby your brain then more or less executes a "painting" based on the information it received, where one can't know the relationship of fhe image in the painting to the information that precipitated the painting (is it a photorealist painting? Abstract expressionism? Impressionism? Etc.) And then what one perceives (I'd say "perceives" really) is the painting that one's brain unconsciously (or preconsciously) executed.

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? — Harry Hindu

What point are you getting at? — dukkha

That the amount of information we acquire about our environment visually is directly tied to the amount of light in the environment.

No, there's a huge difference between seeing a physical object directly, and seeing a representation/model of a physical object. It's the difference between a map and a territory. No matter how accurate a map is, it's still not the territory. — dukkha

What would it be like to see an object directly? Seeing entails using light as a source of information about the world? If you are experiencing the object directly, then you aren't seeing it, you're touching it, and even then that isn't direct, but is more direct than our sense of vision. We can see both the map and the territory thanks to light. No light, no map or territory - at least visually.

What about when we are outside on a sunny day and attempt to look through a window inside a dark house? We can't see what is inside because there is less to no light coming through the window from inside, and the light outside doesn't reflect off the window (because it's transparent) back into our eyes, which is why it appears dark.

Turn the lights on inside and now you have light traveling through the window outwards towards your eye and you can now see inside. Being inside the dark house, you can see through the window because the light is outside traveling through it, but me being on the outside there is no light traveling through the window towards me because I'm on the opposite side of the direction of light.

Transparent objects appear dark when there is no light traveling through, nor being reflected off of them (because they are transparent) from the other side towards my eye. So it all depends on where you are relative to where path of light.

The process is analogically like light entering a camera and creating an image on film. — Terrapin Station

That's indirect realism though. Camera = body/eye. Roll of film = brain. Image is on the film, which is located within the body.

It doesn't matter how accurate/photorealistic this image is, it's still an image. It's still not the physical world which exists in the world outside the camera. Clearly it's you who doesn't know what naive realism is.

That's indirect realism though. — dukkha

No, it isn't. That's why I'm telling you that you're arguing against a straw man. Direct realism is still perception. You're presenting it as if direct realists are attempting to eliminate perception from their theory of perception. They're doing no such thing.

To me, the indirectness or directness of perception isn't based the difference of the image compared to what it represents. It should be a given that the image isn't what is represented. The image is an outcome of various causes and we experience the same image at the end of the same string of causes. We always experience blue when a particular wavelength of light strikes our retina. If it didn't then we'd never be able to make heads or tails of what it is we are experiencing.

The directness/indirectness comes into play as a result of the length of the string of causation. How many steps are there from point A to the last step?

As I explained, our sense of touch is more direct than our sense of vision because we physically come into contact with the object when we touch it. This isn't the case when we see the object. The object doesn't touch our eye (that would hurt). Light touches our eye and we are informed of the object's properties and state via the light that reflects off of it.

The reason why we can rely on the image representing the object's state fairly accurately is because the whole process is lawful, not random. Just as tree rings indirectly inform us of the tree's age, the tree rings were caused by the lawful process of the tree growing throughout the year. So we can rely on tree rings representing the tree's age accurately because they were formed by how the tree grows, which is a lawful, non-random process. We can also rely on our sense of vision because the whole process is lawful and non-random and the same string of causes ends up leaving us with the same experience.

No, it isn't. That's why I'm telling you that you're arguing against a straw man. Direct realism is still perception. You're presenting it as if direct realists are attempting to eliminate perception from their theory of perception. They're doing no such thing. — Terrapin Station

If you believe your visual field is located within a brain you are an indirect realist.

Your perception occurs in your brain, or it "occurs of your brain." Again, direct realists are not saying that perception doesn't involve perception. If you believe that they're effectively denying perception, which is a mental process, then you don't understand what direct realism is.

I don't think direct realists deny perception exists. If you believe that there is a world, and in that world there is a brain, and in that brain is a perception, then you are an indirect realist. This is uncontroversial.

The direct realist position involves the mind being out of the brain and in the world. Their understanding of how vision works, for example, is "light waves travel to the retina which send electrochemical impulses into the brain.... and then one looks at objects in the external world. The eye, for the direct realist are 'windows upon the world'. No perceptions are located within the brain for the direct realist. Sounds for example, are located within the world. The ear and brain just allow the direct realist to perceive the sounds in the external world. The sound perception isn't in the direct realists brain. Colours, the actual way things look (red,blue, etc quales) are for the direct realist located out in the external world. The eye and brain are just a mechanism by which these external existing colours are perceived. The red, blue, green look to things are not located within the direct realists brain, they're out in the world. For the direct realist externally existing objects are literally presented in their experience. The mind essentially superimposing itself upon things in the external world. The 'look' of things exist in the external world. As in the red cup literally still 'looks' red even when it's in the cupboard. The mind just allows one to have access to how the cup looks in itself.

From Stanford Encyclopedia of Philosophy:

Direct Awareness of Material Objects

Before considering whether a case can be made for the second direct realist thesis, we need to look a bit further at the first thesis. How are we to understand the claim that we are “directly” or “immediately” aware of material objects? Here there are at least two initially plausible things that a direct realist can say. First, contrary to what a representative realist view might seem to suggest, our perceptual awareness of material objects is obviously not, at least in ordinary cases, arrived at via anything like an explicit inference from either beliefs about or awarenesses of subjective entities such as sense-data. On the contrary, in most ordinary situations, it is material objects and situations that are the primary and usually the exclusive objects of the perceiver's explicit awareness and thought, with no hint that this awareness has been arrived at via any sort of transition from anything else. Second, as Searle and others have argued, there is an obvious and intuitively compelling way in which perceptual experience seems to directly present physical objects and situations. Direct realists have sometimes spoken here of “openness to the world,” a locution that suggests the way in which such objects and situations seem to be simply present in their own right in experience. The direct realist need not deny (though some have seemed to) that sensory experience somehow involves the various qualities, such as complicated patterns of shape and color, that sense-datum or adverbial views have spoken of, nor even that the perceiver is in some way aware or conscious of these. His point is that whatever may be said about these other matters, from an intuitive standpoint it is material objects and nothing else that are “directly before my mind” — and that any view that denies this obvious truth is simply mistaken about the facts. — SEP

The direct realist is not aware of perceptions which are located within a brain. When he sees a red cup, the 'redness' which he perceives is literally located within the external world. The eyes, brain etc are just a mechanism that allows one to have direct access to the externally existing 'redness'. The redness is NOT located within a perception within a brain! That's the position of representationalism or indirect realism. It does not matter at all how accurate the perception which is located within the brain is. It could literally be a 1:1 copy of the external world. Because it's still a copy!

Anyway, this debate has gone so far off topic. The direct realist would see an image on the surface of clear objects, which is located in the external world. For the direct realist the image would still be there even if nobody was around. (He doesn't realize it's an image though, because it's so 'crisp'). You might say you can't believe there is an image there because there's no plausible physical way by which glass could display an image. But, it is uncontroversial that this is exactly what ulexite does. Ulexite has fiber optic properties which cause an image to displayed on its surface. Same sort of thing is happening with all other physically transparent objects (objects which allow lightwaves to travel through them).

If you believe that there is a world, and in that world there is a brain, and in that brain is a perception, then you are an indirect realist.. — dukkha

Nope. You're wrong. You don't understand what direct realism posits, and that includes that you're not understanding texts such as the SEP entry that you're quoting. Hence that you're arguing against a straw man, as I pointed out long ago in this thread.

Sounds for example, are located within the world. The ear and brain just allow the direct realist to perceive the sounds in the external world. — dukkha

No. Sounds only exist in the mind. Vibrating air molecules are located within the world and sound is a representation of those wavelengths of air molecules. Just as colors don't exist out in the world, they only exist in the mind as representations of wavelengths of light. We don't see wavelengths of light, nor hear vibrating air molecules. If we did, that would be direct realism. We don't, which is why indirect realism is the case.

Your perception occurs in your brain, or it "occurs of your brain." Again, direct realists are not saying that perception doesn't involve perception. If you believe that they're effectively denying perception, which is a mental process, then you don't understand what direct realism is. — Terrapin Station

And what I've been saying is that perception comes in many different forms. We can perceive the world visually, audibly, and via our sense of touch, taste and smell. I have already pointed out that different perceptions can give us different information about an object - like the straw visually appearing bent, but our tactile perception informs us it is straight. If direct realism is true, then why would we have two different perceptions of the same thing? Which perception is accurate?

Direct realism conflates the way things appear and the way they actually are. We don't see wavelengths of light. We see colors.

When Nagel asks "What is it like to be a bat?" Is he asking what it is like to actually be a bat, or what is it like to appear to be a bat?

And what I've been saying is that perception comes in many different forms. We can perceive the world visually, audibly, and via our sense of touch, taste and smell. I have already pointed out that different perceptions can give us different information about an object - like the straw visually appearing bent, but our tactile perception informs us it is straight. If direct realism is true, then why would we have two different perceptions of the same thing? Which perception is accurate? — Harry Hindu

Well, first it's important to remember that direct realism doesn't claim that there are no illusions, or that there is no faulty perception. But aside from that, re "which perception is accurate," the answer is "all of them."

There seems to be another popular straw man in discussions about direct realism online that has it that direct realists are for some reason asserting that one perceives the "entirety" of the objects and phenomena that one perceives. No one is claiming this. For example, when we say that we directly/accurately perceive the moon visually, no direct realist is saying that they also perceive the dark side of the moon visually (with the naked eye on Earth).

So it's rather the case that we're perceiving some subset of properties of the objects and phenomena at hand, and per my idiosyncratic views here, we're perceiving a subset from a particular reference point, where what we're actually talking about is a complex or system, because we're talking about a lot of interacting factors, such as light traveling through an atmosphere. Continuing with my idiosyncratic views, it's also the case that everything is always a particular way at one reference point and (at least some) different ways at different reference points (where I'm talking about actual properties, not (just) perceived properties), and "there are only reference points," or in other words, it's impossible to escape reference points.

So per touch, x is like a, and per vision, x is like b, and so on, and all of those are accurate (ceteris paribus) because they're different subsets of properties. And also, per touch, x is like a to S at reference point 1, and per touch, x is like f to Q at reference point 2, and so on. No two people can experience something from the same reference point, and even the same person can not experience something at the same reference point multiple times, because reference points are unique to time-slices as well as spatial locations.

We always experience blue when a particular wavelength of light strikes our retina. If it didn't then we'd never be able to make heads or tails of what it is we are experiencing. — Harry Hindu

Just splitting hairs here but this is not entirely true. Check out this illusion for example, the same wavelength of orange is striking our retinas but we perceive two different colours:



Objects which appear blue in the day still emit the same 'blue' wavelengths of light at nighttime, just not enough for the cones in our retinas to respond to.

No. Sounds only exist in the mind. Vibrating air molecules are located within the world and sound is a representation of those wavelengths of air molecules. Just as colors don't exist out in the world, they only exist in the mind as representations of wavelengths of light. We don't see wavelengths of light, nor hear vibrating air molecules. If we did, that would be direct realism. We don't, which is why indirect realism is the case. —

Ok. Getting back to the thread topic the question is then, does the brain internally represent physically transparent objects by producing a visual perception of an image displayed on the surface of a transparent object, in much the same way as the brain internally represents ulexite? Or, is the depth which we perceive in glass not an illusion, and the brain is producing a visual representation of the physical objects which exist behind the physically transparent object?

Or, to speak poetically, what is the 'length' of the visual field which the brain produces. Does the visual perception span from your eyes to the surface of the glass, or does it span beyond the glass to the objects behind it? So, when the brain internally represents ulexite, the 'length' of the visual perception is from the eye to the surface of the ulexite. Is it the same for other physically transparent objects (physical objects which allow light to pass through them).

As I explained, our sense of touch is more direct than our sense of vision because we physically come into contact with the object when we touch it.

Well, how do you know you're touching an object? Through sight. But if your sight is indirect then the object you are touching is an internal representation. If you look at the biology of the sematosensory system this makes sense as well. There's nerve cells in your skin which fire off neuronal impulses (in response to various stimuli) to the spinal cord, where some processing may occur, the impulses then travel to the brain for further processing. In much the same way as there's only an incoming process for the visual system (retina responds to light and sends impulses into the brain where a visual perception is produced, i.e. an outgoing gaze isn't then produced which goes in the opposite direction beyond the brain and into the external world beyond), likewise nerve impulses don't travel from the sematosensory receptors to the brain, and then you directly feel the physical object. It's more like in the brain there's an internal model of the body and the brain collates all the different data coming from the various sensory organs into this model. The touch perception exists internally within the brain, the objects which you see yourself touching are internal visual representations of physical objects in the external world.

Heres a representation of a cortical homunculus. It shows the parts of the brain which are devoted to sematosensory data coming from those particular regions of the body. Note how the fingers take up far more brain power than say, the back. There's a far higher density of sematosensory receptors in the fingers compared to the back.



This is what's entailed by indirect realism. You don't have indirect access with some senses and direct access with others. Rather the brain produces a cohesive onboard self/world model, which is what you have epistemic access to only. The world around you, your body, other people, it's all an internal (private) representation. You exist entirely cut off from the physical world.

Well, first it's important to remember that direct realism doesn't claim that there are no illusions, or that there is no faulty perception. But aside from that, re "which perception is accurate," the answer is "all of them." — Terrapin Station

This doesn't make any sense. If different senses provide different information that contradict, then they both can't be right. You can only be right if you say that you are experiencing two different things - one is you are experiencing a straight stick via touch and you experiencing bent light via vision. It seems that direct realism has simply co-opted indirect realism and renamed it "direct realism".

Direct realism redefines illusions out of existence. If illusions are what you are suppose to experience as a result of particular causes, then you aren't experiencing an illusion. In fact there are no illusions. There are simply misinterpreted sensory experiences.

There seems to be another popular straw man in discussions about direct realism online that has it that direct realists are for some reason asserting that one perceives the "entirety" of the objects and phenomena that one perceives. No one is claiming this. For example, when we say that we directly/accurately perceive the moon visually, no direct realist is saying that they also perceive the dark side of the moon visually (with the naked eye on Earth). — Terrapin Station

That isn't my argument. I'm not arguing that we don't see an object in it's entirety and that entails indirect realism. I'm arguing that we have contradicting information about one object and that is evidence of indirect realism.

This is what's entailed by indirect realism. You don't have indirect access with some senses and direct access with others. Rather the brain produces a cohesive onboard self/world model, which is what you have epistemic access to only. The world around you, your body, other people, it's all an internal (private) representation. You exist entirely cut off from the physical world. — dukkha

If I were entirely cut off from the physical world, then how do I experience it? You are promoting dualism without the explanation as to how the mental can interact with the physical.

There is no mental vs. physical in the world other than as categories in the mind. The world is just one substance - one of information - where information is simply the relationship between cause and effect. The cause is not the effect but they are linked by time and space and exist together within the same medium. What we experience is the effect. The cause is "out there" in a different place and time. We can only experience the effect and never the cause, which is why indirect realism is the case, yet they are linked so as to prevent any separation that would require an explanation of how one can rely on their experiences being informative.

Well, how do you know you're touching an object? Through sight. — dukkha

Then how does a congenitally blind person know when they are touching an object?

If different senses provide different information that contradict, — Harry Hindu

The point is, and this would have been clear had you understood all of my comment, that the information doesn't contradict. For one, when we're talking about different senses, obviously we're talking about different information-- visual information is different than tactile information, for example; light waves are different that surface textural properties, etc. Hence why I noted that we perceive information about some properties, where that's different on different occasions, etc., and via a "complex" or a system--things aren't in, and we're not perceiving them in, vacuums.

I don't know why you're claiming that direct realism dispenses with illusions. It explicitly does not.

Re the comment about it being something other than direct realism, again, this appears to be a case of simply not being familiar with or not understanding what the conventional distinctions between the two are.

The point is, and this would have been clear had you understood all of my comment, that the information doesn't contradict. For one, when we're talking about different senses, obviously we're talking about different information-- visual information is different than tactile information, for example; light waves are different that surface textural properties, etc. Hence why I noted that we perceive information about some properties, where that's different on different occasions, etc., and via a "complex" or a system--things aren't in, and we're not perceiving them in, vacuums. — Terrapin Station

We're not talking about different information. Both senses provide different representations about the same thing - the shape of the stick. What is the shape of the stick?

To ask how something appears independent of looking at it, or independent of how light interacts with it, is a nonsensical question. How something appears has to do with how it interacts with light for some visual processing system to then have access to that reflected light and process it for some purpose. All of this has to occur for any appearances to occur.

So the real question is, is how something appears how it really is? We're asking about the difference between a representation and reality. What we have direct access to is the representation, not the reality. The reality can only be accessed indirectly through it's representation. So if it is your argument that we see exactly how some thing appears then you are still saying that all we have direct access to is a representation, not the reality. So, at best you can call your stance direct representationlism, not direct realism. There could never be anything like direct realism. Effects are not their causes. Effects are the result, or the emergent property, of various causes coming together.

How an object appears doesn't just provide us information about the object, but also about the amount and wavelength of light in the environment and also about the state of your visual system. All of these things are represented in the experience of the color blue.

If you can only get at the "realness" of an object by how it interacts with other things then either the object doesn't exist independently of it's interactions with other things, or you can never get at the object as it exists independent of it's interactions with other things. This why direct realism can never be the case.

But this is just what I was talking about in my comment. The properties of everything extant are relative to the reference point we're talking about, and there are no "reference point free reference points." In other words we're always talking about some reference point or other, and that reference point is different than other reference points.

And we are talking about different properties, because we're talking about light waves and how they react with something as part of a system versus "topological" surface qualities and how they interact with different things. That's what the world is really like. It's not really like some abstracted simplification where you pretend that properties are not relative to reference points and so on.

But this is just what I was talking about in my comment. The properties of everything extant are relative to the reference point we're talking about, and there are no "reference point free reference points." In other words we're always talking about some reference point or other, and that reference point is different than other reference points.

And we are talking about different properties, because we're talking about light waves and how they react with something as part of a system versus "topological" surface qualities and how they interact with different things. That's what the world is really like. It's not really like some abstracted simplification where you pretend that properties are not relative to reference points and so on. — Terrapin Station

We're not talking about different properties. We're talking about one property - the shape of the stick. What is the shape of the stick independent of any senses accessing it? Does the stick have a shape independent of any sensory system accessing it? Does the stick exist how it appears in my mind or is it something else? Does the stick exist when I'm not accessing it via any sensory system?

If that is what the world is really like then you're an idealist/solipsist? It seems to me that it is what perception is like, not the world, and perception is only one process out of many that make up the world - a process that creates colors and sounds which don't exist in any other part of the world except right here in our heads.

We're not talking about different properties. We're talking about one property - the shape of the stick. What is the shape of the stick independent of any senses accessing it? — Harry Hindu

I don't believe that you're understanding me. Let's try it this way:

We're talking about the shape of the stick from what reference point?