I might be more in the direct realist camp, so I'll try to answer this — plaque flag

As an Indirect Realist, I agree with everything you wrote in your post. It is interesting that you used Kant, in today's terms an Indirect Realist, to support your case.

Kant discussed "Existence", in that there are things-in-themselves, "Humility", in that we know nothing of things-in-themselves and "Affectation", in that things -in-themselves causally affect us. Kant's concept of a thing-in-itself is not that of a Direct Realist.

We need not assume in the first place that we are trapped behind a wall of sensations. This methodological solipsism is unjustified, in my view. Concepts are public. They exists within a system of norms for their application. This is why bots can talk sensibly about pain and color. — plaque flag

Wittgenstein's beetle in the box analogy in para 293 of Philosophical Investigations may be used as an argument against Direct Realism. The Direct Realist would argue that if two people are looking at the same object in the world, as both will be perceiving the same object in the world immediately and directly, their private mental images must be the same, meaning that each will know the others private sensations. However, this wouldn't agree with Wittgenstein's para 272 that each of us has private experiences not known by others.

Wittgenstein's beetle in the box analogy also explains how a public language is possible, even though our private experiences are unknown to others. In a public language, our private experiences, as with the beetle, drop out of consideration.

I assume that both the Indirect and Direct Realist would agree:
1) All our information about things external to our senses comes through our senses.
2) We directly perceive things this side of our senses, such as apples, trees, mountains, etc.
3) Science tells us that the properties of things the other side of our senses, such as wavelength, are different to the properties this side of our senses, such as the electrical signal that travels up the optic nerve to the brain.
4) Even though we each have private experiences, we can talk about these private experiences using a public language, allowing us to live in social communities.

The Indirect Realist would argue that the world outside our senses is different to the world we perceive this side of our senses. The Direct Realist would argue that not only is the world outside our senses the same as the world we perceive this side of our senses but also that we directly know the world outside our senses.

The question for the Direct Realist is how is it possible to know that the world outside our senses is the same as the world we perceive this side of our senses, when science tells us that what is on the other side of our senses is different to what is this side of our senses.

The Direct Realist agrees that pain doesn't exist external to the senses of any perceiver, but argues that the colour red does.

How does the Direct Realist explain, given that all their knowledge of the world external to their senses comes through their senses, how the perceiver knows that one perception is not direct, eg, pain, but another perception is direct, eg, the colour red ?

Why would there be properties? Aren't these just predicates? — Moliere

Predicates are distinct from properties. Predicates are linguistic whilst properties are extralinguistic. Predicates are tied to particular languages, in that schwarz is tied to German as black is tied to English, but the property black is tied to neither. There is a real world out there and the things in it have properties whether or not there are any languages or language-users.

To my understanding, there are two types of Direct Realism, Phenomenological Direct Realism (PDR) and Semantic Direct Realism (SDR). PDR is an direct perception and direct cognition of the object "tree" as it really is in a mind-independent world. SDR is an indirect perception but direct cognition of the object "tree" as it really is in a mind-independent world. As PDR is extralinguistic and SDR is linguistic, properties exist in PDR whilst predicates exist in SDR.

I can perceive that an apple has the property of greenness even if I don't know the name of that particular shade of green, but I need the predicates within language in order to say that "the apple is green".

in relation to causation no direct realist would say "we can see causal chains all the way back" because we are situated in time — Moliere

But that is exactly what the Direct Realists is saying. The Direct Realist is saying that they directly know the apple, not just how the apple seems, even though there is a causal chain through time from the apple to our perception of the apple.

The Direct Realist holds a contradictory position. First, that they cannot see through causal chains backwards through time and second that they can directly see the prior cause of a perception.

Rather than saying a direct realist would hold that we see reality as it is, that the substrate is real and we directly perceive it, I'd say that the direct realist states that there's nothing indirect. — Moliere

In the absence of a Direct Realist arguing their case, I would have thought that your representation is the opposite of what a Direct Realist believes, in that it is surely the case that the Direct Realist believes that "we see reality as it is, that the substrate is real and we directly perceive it".

Well -- maybe we need new terms then. — Moliere

Perhaps the term "Direct Realism" should be thought of as a name rather than a description, in the same way that "Transcendental Idealism" is neither transcendental nor idealism.

Other names that incorrectly appear to be descriptions are: Red Panda, white chocolate, titmouse, gravy train, buffalo wing, cat burglar, butterfly, coat of arms, lady bug, Asian flu, Chinese checkers, Arabic numerals, the Fibonacci sequence, the Pythagorean theorem , koala bears, king crabs, glow-worms, fireflies, horned toad, slow worms, starfish, jellyfish, velvet ants, strawberries, peanuts, Panama hats, English horns, Jerusalem artichokes, Bombay duck, The Isle of Dogs, catgut and funny bone.

I could then say that yesterday I was thinking about the meaning of Direct Realism whilst eating several spicy buffalo wings.

In TPF discussions I'll stick with anti-realist Direct Realist -- it seems to fit, given what's been said. — Moliere

That's like saying you are an Atheist Christian, or a vegan carnivore.

One thing that cause and effect naturally invokes is time.............Then you have to have a theory of cause and effect which is usually to say they are events, and effects are those which come after causes. But what is an event? — Moliere

The Indirect and Direct Realist would agree that perception is a direct awareness of properties existing in the mind, such as the direct perception of the colour red.

Both the Indirect and Direct Realist would agree that it is only through our senses that we know the external world.

Science tells us that the object in the external world causing our perception of the colour red has a wavelength of 700nm.

The Indirect Realist argues that the properties existing in our mind, the colour red, are different to the properties of the object in the external world that caused them, a wavelength of 700nm

The Direct Realist argues that the properties existing in our mind, the colour red, are the same as the properties of the object in the external world that caused them, the colour red.

In effect, the Direct Realist is arguing that the properties of an effect at a later time are the same as the properties of its cause at an earlier time.

The Direct Realist is arguing that the properties of an effect are the same as the properties of its cause

But we know this is not the case, When getting a headache from looking at a bright light, we know that bright lights are not in themselves headaches. When glass breaks from being hit by a stone, we know that stones in themselves are not breaking glass. When enjoying reading a book, we know that books in themselves are not enjoyment.

The Direct Realist's position that the properties of an effect are the same as the properties of its cause cannot be justified.

It's not just the philosophers who generate a multitude of theories of causation — Moliere

Is it any more complicated that for every effect there is a cause.

I wouldn't say I know that, but it's interesting to attribute minds to bacteria. Would they have the concept of causality? — Moliere

They might well have. The New Scientist article Why microbes are smarter than you thought discusses communication, decision-making, city living, accelerated mutation, navigation, learning and memory.

evolution doesn't have a point, does it? — Moliere

Not in a teleological sense. Sean Carroll in his lecture The Big Picture: From the Big Bang to the Meaning of Life touches on evolution and causality.

Indirect Realism holds that perception is a direct awareness of objects and events existing in the mind, and an indirect awareness of objects and events existing in a mind-independent world.

Direct Realism holds that perception is a direct awareness of objects and events existing in the mind, and a direct awareness of objects and events existing in a mind-independent world.

Both the Indirect and Direct Realist would agree that it is only through our senses that we know the mind-independent world.

The Direct Realist would need to explain the circular problem as to how on the one hand we can have direct knowledge of things as they exist independently of our sensations about them in a mind-independent world yet on the other hand we cannot have knowledge of these things independently of our senses.

The story from evolution to concept isn't understood — Moliere

Though we do know that after 3.5 billion years of life's evolution, the concepts in the human mind are more complex that the concepts in the mind of the earliest bacteria.

My scenario pointed out that the philosophers have come up with at least three distinct theories of cause, rather than a total absence of the notion of cause -- giving me reason to doubt that cause is innate (else wouldn't they have come up with the same theories?). — Moliere

Ten philosophers expert in the same field will have ten different theories. As Searle said:
"I realize that the great geniuses of our tradition were vastly better philosophers than any of us alive and that they created the framework within which we work. But it seems to me they made horrendous mistakes."

I'd say the reason people learn this notion so often has more to do with our environment than it does with ourselves. — Moliere

Then what has been the point of 3.5 billion years of evolution if an instinctive feel for causality is not part of the structure of the human brain.

I think "causation" is one of those habits which we learn from those around us who teach us how to use it. It's different from what we feel, i.e. red or pain...So it's more likely that we're inventing causation than it's innate, given the evidence of the intelligent and creative. — Moliere

If causation was not innate and was something learned, as with all things, some people would learn it and some wouldn't.

Imagine someone who hadn't leaned about causation, who were oblivious to the concept of cause and effect. Would they be able to survive in a world where things happen, where future situations are determined by past events. Suppose there was someone who treated the law of causation as optional, who turned a blind eye to the fact that present acts have future consequences. Why would they eat, why would they drink, why would they move out of the path of a speeding truck, why would they study, why would they do anything, why wouldn't they just curl up in a corner of the room.

I would suggest that such people would quickly die out, to be inevitably replaced by those well aware that present acts do have future consequences.

After life's 3.5 billion years of evolution in synergy with the unforgiving harshness of the world it has been born into, something as important to survival as knowing that present acts do lead to future consequences will become built into the genetic structure of the brain, meaning that within the aeons of time life has survived on a harsh planet, knowledge that present acts do lead to future consequences will become an instinctive part of human nature.

As with other features of the human animal, an instinctive feel for causation will be no different to other things we feel, such as pain and the colour red.

However, I think I'd call myself a realist, rightly, yet deny there even is a sub-stratum. — Moliere

Realism is defined as the assertion of the existence of a reality independently of our thoughts or beliefs about it, so a Realist wouldn't deny that there is a sub-stratum.

I wouldn't reduce reality to either phenomenology or semantics (or science) — Moliere

The Phenomenological Direct Realist believes they directly perceive something existing in a mind-independent world even if they don't know its name. The Semantic Direct Realist believes they directly perceive an apple existing in a mind-independent world.

For the Direct Realist, the terms phenomenology and semantics distinguish important features of their view of reality.

That's because without access to the substrate there's no way to check our inferences, or a way to check if there is a relationship between the substrate and the surface. We could only check it against the surface. It may match the substrate, but we'd never know due to its indirectness. — Moliere

That's true, but I have an innate belief in the law of causation, in that I know that the things I perceive in my mind through my senses have been caused by things existing outside my mind in a mind-independent world.

My belief in the law of causation is not based on reason, but has been been built into the structure of my brain through 3.5 billion years of life's evolution within the world.

I have no choice in not believing in the law of causation as I have in not believing I feel pain or see the colour red.

Effect: private sense data that cannot be publicly verified as either true or false. — Richard B

I think everyone would agree with this, apart from perhaps a psychic empath.

Cause: an unknowable something that is out of reach because all we know for certain is our private sense data. — Richard B

Very true.

They are no longer apples the moment we stop calling them apples — Moliere

As an Indirect Realist, my belief is that as apples exist in the mind, exist in perception, cognition and language and not in a mind-independent world. As you say, they can therefore be brought into existence and removed from existence just by the power of thought.

But the indirect realist wants to assert, all we have is perception, and there's something real out there underneath it all as an inference, as I understand it in this thread, starting from naive realism -- that what we see is what's the case, modified to our perception. — Moliere

I agree that there is the surface of perception, cognition and language which is real and we have direct access to, and there is a substratum which is also real. The Indirect Realist believes that they can only make inferences about what exists in this substratum, whilst the Direct Realist believes they can directly perceive what exists in this substratum.

But if so I think it has to be established by some other means than by looking at change, — Moliere

There are different approaches to Direct Realism. Phenomenological Direct Realism (PDR) is an direct perception and direct cognition of the object "tree" as it really is in a mind-independent world. Semantic Direct Realism (SDR) is an indirect perception but direct cognition of the object "tree" as it really is in a mind-independent world.

As language is one aspect of cognition, the change in object from apple to non-apple is more relevant to SDR than PDR. As you say " They are no longer apples the moment we stop calling them apples".

However, I agree that change is not as relevant to PDR as it is to SDR. The following is more relevant to PDR.

Both the Indirect and Direct Realist agree that the substratum is real and exists. They both perceive, cognize and talk about "apples". The Direct Realist believes that apples exist in a mind-independent world, the Indirect Realist doesn't.

I can perceive things that I don't have words for. For example, exotic fruits of Asia. Therefore, it's possible to be able to perceive an apple without knowing that it has been named "apple".

As both the Indirect and Direct Realist agree they perceive change, we cannot use change to determine who is correct. Therefore, just consider the picture at 230 days. As both the Indirect and Direct Realist are able to perceive things they have no name for, remove any reference to the name" apple". The Direct Realist would argue that the object at day 230 exists as it is seen in a mind-independent world, whilst the Indirect Realist would argue that it doesn't.

The thing perceived at 230 days is part ochre at the top and part umber at the bottom, contained within a circle and supporting a short vertical line above. Reducing, we have a straight line, a circle, some colour and relationships between them.

The Indirect Realist would propose that these features exist only the mind. The Direct Realist would propose that these exist not only in the mind but also in a mind-independent world. Both the Indirect and Direct Realist agree that these features exist in the mind, however the Direct Realist also proposes in addition that these features also exist in a mind-independent world.

Both the Indirect and Direct Realist would agree that we gain all our information about a mind-independent world through our senses. The Direct Realist argues that just from a knowledge of our sensations, we are able to have a veridical knowledge of the cause of these sensations. I would argue that from knowing just an effect, it is impossible to directly know its cause.

We know we perceive the colour red, yet the Direct Realist argues that the cause of our perceiving red is a colour red existing in a mind-independent world. We know we perceive a circle and line, which are particular spatial relationships between individual points, and we know we perceive particular spatial relationships between these shapes, yet the Direct Realist argues that the cause of our perceiving spatial relations is the ontological existence of spatial relationships in a mind-independent world.

For PDR to be a valid theory, it must justify at the least that colours and spatial relations ontologically exist in a mind-independent world.

Argument against Direct Realism



Semantic Direct Realism (SDR) says that we have direct cognition of the object "apple" as it really is in a mind-independent world. Therefore, for SDR, apples exist in a mind-independent world, whether they are perceived or not.

However, as the apple rots, at what exact moment in time in a mind-independent world does the apple disappear from existence. A human observer may judge when the apple disappears from existence, but what is there in a mind-independent world that determines when the apple disappears from existence ?

As Wittgenstein pointed out, somewhere in PI, pointing at something only works if the other folk around you understand that they have to follow the direction of your finger - and that is already to be participants in a sign language. — Banno

It follows that Wittgenstein's language game is incompatible with Semantic Direct Realism.

Definitions of Direct Realism
I defined Direct Realism as either:
1) Phenomenological Direct Realism (PDR) is a direct perception of the object "tree" as it really is in a mind-independent world
2) Semantic Direct Realism (SDR) is an indirect perception but direct cognition of the object "tree" as it really is in a mind-independent world

Wikipedia on Naive Realism writes: "According to the naïve realist, the objects of perception are not representations of external objects, but are in fact those external objects themselves."

You wrote that: "Direct realism is where what we talk about is the tree, not the image of the tree or some other philosophical supposition."

In summary, some definitions of Direct Realism are limited to perception, free of language, and some definitions require cognition, involving language.

However, as the argument from illusion makes too strong case against Phenomenological Direct Realism, Semantic Direct Realism remains the only likely possibility.

The difference between perception and cognition
In perception, the brain receives sensory input through the five senses which it processes as simple and complex concepts, simple concepts such as the colour green, and complex concepts such as a tree. In cognition, the brain combines these concepts using memory, reasoning and language to understand what has been perceived, enabling propositions such as "the tree is green".

As language is part of cognition, I can perceive things without needing a language. There are many things in the world that I perceive that I have no words for.

The act of pointing
I agree that I have been assuming that the word "tree" in language is pointing at a picture of a tree existing in a mind-independent world.

However, you note that the act of pointing is already part of the language game, meaning that what is being pointed at exists in a world, but the world of the language game, not a mind-independent world.

Wittgenstein in para 31 of PI writes that the act of pointing only works if the observer has previous knowledge of what is being pointed out:
"Consider this further case: I am explaining chess to someone; and I begin by pointing to a chessman and saying: "This is the king; it can move like this, . . . . and so on."—In this case we shall say: the words "This is the king" (or "This is called the 'king' ") are a definition only if the learner already 'knows what a piece in a game is'".

Therefore, words being used in the language game are not pointing out objects in a mind-independent world, but are pointing out objects existing within the language game itself

However, Semantic Direct Realism is the position that we have a direct cognition of "trees" as they really are in a mind-independent world, allowing us to make the statement that "trees are green" is true IFF trees are green in a mind-independent world.

As Wittgenstein's language game says that the statement "trees are green" does not point to something in a mind-independent world but rather points to something already existing in language, Wittgenstein's language game is incompatible with Semantic Direct Realism, which says that "trees are green" does point to something existing in a mind-independent world.

Summary
IE, Wittgenstein's language game is incompatible with Semantic Direct Realism.

Why would you submit this as an example as a counter to direct realism if you don’t have idea what it is countering? — Richard B

I gave my definition of Direct and Indirect Realism here.

Best answered by a Direct Realist, as I don't know of anything that a Direct Realist has direct cognition of that isn't a representation of something in a mind-independent world.

Are you claiming that for the direct realist to be consistent with their position that when the person walks away, their height must appear the same the further they move away from the observer? — Richard B

Perhaps best answered by someone who believes in Direct Realism.

The other, a metaphysical theory positing “sense data” which is in principle private, unaccessible, and with un-unverifiable claims. Lastly, as I have been arguing irrelevant to the meaning of the language used. — Richard B

The Indirect Realist agrees that private experiences are private, but as Wittgenstein explains in para 293 of PI, language games work because private experiences drop out of consideration as irrelevant: "That is to say: if we construe the grammar of the expression of sensation on the model of 'object and designation' the object drops out of consideration as irrelevant."

How can the Direct Realist justify that the colours red and blue exist in a mind-independent world.

The Direct Realist argues that they have direct cognition of the colours red and blue as they really are in a mind-independent world. meaning that the colours red and blue exist in a mind-independent world.

Red covers the range 625 to 750nm and blue the range 450 to 485nm.

In a mind-independent world, what determines that a wavelength of 650nm has something in common with a wavelength of 700nm, yet nothing in common with a wavelength of 475nm ?

Defining Direct Realism.

Some Direct Realists argue for Phenomenological Direct Realism (PDR), aka casual directness, a direct perception and a direct cognition of the object as it really is, and some argue for Semantic Direct Realism (SDR), aka cognitive directness, an indirect perception but direct cognition of the object as it really is.

The argument from illusion makes a strong case against PDR.

Supporters of SDR would argue that "Direct realism is where what we talk about is the tree, not the image of the tree or some other philosophical supposition."

However, it is equally true that "Indirect realism is where what we talk about is the tree, not the image of the tree or some other philosophical supposition."

As an Indirect Realist I directly see a tree, I don't see a model of a tree. Searle wrote "The experience of pain does not have pain as an object because the experience of pain is identical with the pain". Similarly, the experience of seeing a tree does not have a tree as an object because the experience of seeing a tree is identical with the tree.

Something else is needed to distinguish Semantic Direct Realism from Indirect Realism.

One could write:

Phenomenological Direct Realism (PDR) is a direct perception of the object "tree" as it really is in a mind-independent world

Semantic Direct Realism (SDR) is an indirect perception but direct cognition of the object "tree" as it really is in a mind-independent world

Indirect Realism is a direct perception and direct cognition of the object "tree" as it really is in the world existing in the mind, with the belief that although there is no "tree" in a mind-independent world, there is something in a mind-independent world that has caused such perception and cognition.

And as Wittgenstein pointed out in the first few pages of PI, you would thereby, already be participating in a language game, and so trying to explain meaning by making use of meaning. Then he cut to the chase: Stop looking for meaning, and instead look at use. — Banno

There are two aspects: i) does a potential word have a use, ii) given a word has a use, what does the word mean.

From my position of Neutral Monism, within a mind-independent world are elementary particles, elementary forces and space-time, and relations don't ontologically exist.

Does a potential word have a use



For the mind, some possible relations of the parts are useful within the language game and the broader life, and some aren't. For example the shapes "mraba" and "msalaba" are useful, but the shape with the parts ADI isn't. Only those shapes which are useful are named, and shapes which aren't useful are not named.

For example, the word "peffel", being part my pen and part the Eiffel Tower, has little use in either the language game or broader life, and cannot therefore be found in the dictionary.

Given a word has a use, what does the word mean



It is an undisputable fact that naming using Hume's constant conjunction of events works. It may not completely work first time as it is an iterative process, but it clearly works.

Given that the word "ngoe" has a use within the language game and broader life, what does "ngoe" mean. More broadly, what does "mean" mean.

Meaning is neither in the word "ngoe" or the picture of a ngoe, meaning is in the link between the word "ngoe" and the picture of a ngoe.

We cannot say that the word "ngoe" has a meaning, we cannot say that the picture of an ngoe has a meaning, but we can say that the link between the word "ngoe" and the picture of a ngoe has a meaning.

The link between the word and the picture is where the meaning resides.

Upon the completion of the experiment, an indirect realist walks in to see the results. They are not sure what to think. Surely, they thought that even though they are reporting the community accepted color word for each object correctly, they must be having different a “experience” of color since different neuron cluster are lighting up for each individual...........The indirect realist has no way of knowing which color individual A or B is having in any of these “private experiences” of color based on these results. But how could they ever make sense of these results since there is no private language we could use to understand anyway of what is going on inside their “heads.” As Wittgenstein says in PI 293, “That is to say: if we construe the grammar of the expression of sensation on the model of ‘object and designation’ the object drops out of consideration as irrelevant.” — Richard B

Your post lays out my position as an Indirect Realist.

1) The Indirect Realist doesn't need a private language to have the private experience of a colour.

There are many things I see that I don't have a word for. This doesn't stop me from seeing them.

2) Wittgenstein's PI 293 is a good explanation why Indirect Realism is a workable theory.

PI 293 explains how there can be a public language even though each person's private experiences may be unknown to anyone else.

I would argue that the word "grue" refers to their private experiences, which are different, despite the shared public use. — Michael

I agree, Indirect Realism is a workable theory.

Don't you mean to say that Wittgenstein's beetle in the box analogy justifies talk of indirect realism in relation to the third-personal public concept of perception, but that this doesn't justify talk of indirect-realism in the case of one's own perception? — sime

From the third-person, Wittgenstein's beetle in the box analogy shows that Bill and Bob can carry on a conversation even if they don't know what is in each other's mind. From the first-person, I could be Bill, and still be able to carry on a conversation with Bob.

consider the irrealist understanding of the beetle on the box — sime

Other than a general estrangement from our generally accepted sense of reality, I don't know Goodman's theory.

Given that each individual only has access to his or her private colour, and uses his or her mother-tongue in a bespoke private fashion when referring to the "shared" circle, then what is the purpose of colouring in the shared circle? — sime

I agree, henceforth I will remove the colour from the circle.

Following this line of thought further, one could even deny the very existence of a shared circle, as part of a strategy for defending direct-realism for all perceivers — sime

I agree, as my belief is in neutral monism, where in a mind-independent world there are only elementary particles, elementary forces and space-time. In a mind-independent world there are only parts and no wholes such as circles, trees, colours, etc.

Better yet, to be consistent with Wittgenstein's view of “private language” one should remove the colors inside the heads of the figures. — Richard B

Wittgenstein p 293 PI
Suppose everyone had a box with something in it: we call it a "beetle". No one can look into anyone else's box, and everyone says he knows what a beetle is only by looking at his beetle.—Here it would be quite possible for everyone to have something different in his box.

Wittgenstein writes that everyone says there is something in their head, even if no one else knows what it is, so I cannot leave Bills' head blank. It may be the colour yellow, but it may not.

to be consistent with indirect realism and to prevent any real-world bias, it would be best not to colour the circle in the middle — Michael

I agree that not colouring the circle would be more consistent with Direct Realism.

the same kind of light will trigger the same kind of experience — Michael

Yes, in practice this must be the case, as Bill and Bob are the product of the same 3.5 billion years of evolution, they share 99.9 % of their genetic makeup and they share the same common ancestor, Mitochondrial Eve.

Knowing these facts, Bill and Bob will agree they most likely have had the same private experience and therefore can sensibly name it "grue".

The private language argument is that such a thing cannot be understood in a coherent fashion. That there can be no private languages. That such a thing could not count as a language. — Banno

I agree.
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When the indirect realist says "I see the Earth", they are referring to the brown thing. When the direct realist says "I see the Earth", they are referring to the Earth. — Banno

This is misleading wording. To say that the Direct Realist is referring to the Earth is pre-judging that the Direct Realist is in fact correct in their belief that they are referring to the Earth.

Better wording would be: When the indirect realist says "I see the Earth" they believe they are directly seeing a representation of the Earth. When the direct realist says "I see the Earth", they believe they are directly seeing the Earth.

The question is, who is right.
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Summarising, what the private language argument shows is that one cannot construct a private language that is about one's private sensations. If indirect realism holds that what we see is not the world but a private model of the world, then one could not construct a language about that private model. — Banno

Indirect Realism doesn't need to construct a private language about one's private sensations. I can have the private sensation of a colour without the necessity of having to describe it in words, or of having a private language.



For example, the colour blue has been named "Blue" in a public performative act in the English language, and both Bill and Bob know this.

Note that the public word "blue" and the public colour blue are both objects in the world. For clarity, using the use-mention distinction, the blue in the object "blue" is a "mention", whilst the blue in the object with the colour blue is a "use".

It may be that when looking at the public colour blue, Bill has the private experience of yellow and Bob has the private experience of red, but both Bill and Bob have linked their private experience with the public word "blue", thereby allowing them to talk about objects in their shared world.

For example, if Bill asks Bob to pass over the "blue" object, even though Bill has the private experience of yellow and Bob has the private experience of red, Bob will successfully pass over the object Bill intends.

Indirect Realists can engage in a public social language without needing to be able to describe their private sensations.

Wittgenstein in para 293 in PI describes how everyone's private sensations may be different:
If I say of myself that it is only from my own case that I know what the word "pain" means—must I not say the same of other people too? And how can I generalize the one case so irresponsibly? Now someone tells me that he knows what pain is only from his own case!——Suppose everyone had a box with something in it: we call it a "beetle". No one can look into anyone else's box, and everyone says he knows what a beetle is only by looking at his beetle.—Here it would be quite possible for everyone to have something different in his box.

Wittgenstein continues that the private sensation has no place in a public language, and even if we do use the word "pain" in a public language it doesn't explain the sensation, only indicate that there is some kind of sensation
One might even imagine such a thing constantly changing.—But suppose the word "beetle" had a use in these people's language?—If so it would not be used as the name of a thing. The thing in the box has no place in the language-game at all; not even as a something: for the box might even be empty.—No, one can 'divide through' by the thing in the box; it cancels out, whatever it is.

Wittgenstein continues that the private sensation drops out of consideration within a public social language.
That is to say: if we construe the grammar of the expression of sensation on the model of 'object and designation' the object drops out of consideration as irrelevant.
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Treating this as a reductio, we do have language about the world, and therefore we talk about the world, and not about our private world-models. At least that form of indirect realism is wrong. — Banno

Indirect Realism accepts they have private sensations, but as argued by Wittgenstein in his beetle in the box analogy, such private sensations drop out of consideration within a public social language as irrelevant.

Wittgenstein's beetle in the box analogy justifies Indirect Realism.

"Ngoe" means at least a third of the picture is green? Or the picture is an odd number from the left? — Banno

Good first attempt. We are on the path to successful communication, definitely an iterative process. It's a bit like the Twenty Questions parlour game using deductive reasoning and creative thinking.

I will have to come up with five more pictures that excludes at least a third of the picture of the "ngoe" being green and excludes "ngoe" being an odd number.

As Wittgenstein said in para 32 of PI:
"Someone coming into a strange country will sometimes learn the language of the inhabitants from ostensive definitions that they give him; and he will often have to guess the meaning of these definitions; and will guess sometimes right, sometimes wrong."

An illiterate deaf mute with no language can see a tree "in their mind". They just won't call it "tree"...I've seen many animals that I don't have a name for...But perception doesn't depend on meaning — Michael

I agree, perception doesn't depend on meaning. There is an asymmetry between meaning and perception.

You need to read up on the use-mention distinction. — Michael

Both the Indirect and Direct Realist directly perceive a tree in their minds. For both the Indirect and Direct Realist, the tree they perceive exists in the world. Note that Wittgenstein in Tractatus didn't specify where this world existed.

Example of "the tree is green" is true IFF the tree is green
"The tree is green" being in quotation marks is within language. The tree is green not being in quotation marks is in the world.

For the Indirect Realist, the world in which the tree exists is in their mind. For the Direct Realist, the world in which the tree exists is in a mind-independent world.

The meaning of the word "tree" has nothing to do with perception — Michael

If that were true, you would know the meaning of the word "mlima" even if you had never perceived one.

You could argue that even if you have never perceived a "mlima", it could be described to you, such that a "mlima" consists of "mwamba" and "theluji". But this doesn't solve the problem, in that you you cannot know the meaning of either "mwamba" or "theluji" until having perceived them. Sooner or later, meaning depends on perception. In Bertrand Russell's terms, knowledge by acquaintance.

Who told you what the name of the effect was? — Isaac

In a sense, no one needs to tell me the name of the image that I perceive. I would assume that just from five pictures you could hazard at a guess at the meaning of "ngoe". I discover the name from a constant conjunction of events.

This is a misreading of the private language argument. — Banno

My proposal is that Wittgenstein's Philosophical Investigations does not support Direct Realism.

Direct Realism argues that we perceive objects in the world as they really are, immediately and directly.
If Direct Realism is true, one person's private experience of something in the world, such as a tree, will be the same as another person's private experience of the same tree, meaning that each person will know the other person's private experiences.

Wittgenstein argues that nobody can know another person's private experiences
In para 272 of PI, Wittgenstein writes that nobody can know another person's private experiences:
"The essential thing about private experience is really not that each person possesses his own exemplar, but that nobody knows whether other people also have this or something else. The assumption would thus be possible—though unverifiable—that one section of mankind had one sensation of red and another section another."

The Private language argument prevents talking about or discussing the pros and cons of Indirect and Direct Realism
There is an excellent and informative article in Wikipedia, the Private language argument that I always refer to.

The Wikipedia article Private language argument notes that the private language argument argues that a language understandable by only a single individual is incoherent, from which it follows that there is no language that can talk about or describe inner and private experiences.
1) The private language argument argues that a language understandable by only a single individual is incoherent,
2) If the idea of a private language is inconsistent, then a logical conclusion would be that all language serves a social function.
3) For example, if one cannot have a private language, it might not make any sense to talk of private experiences or of private mental states.
4) In order to count as a private language in Wittgenstein's sense, it must be in principle incapable of translation into an ordinary language – if for example it were to describe those inner experiences supposed to be inaccessible to others

Direct Realism is the position that our inner experience of an object in the world is direct and immediate. Indirect Realism is the position that we cannot know whether or not our inner experience of an object in the world is direct and immediate.

As Wittgenstein's private language argument argues that no language can talk about or describe inner and private experiences, it follows that the pros and cons of Indirect and Direct Realism is not something that can be talked about or described.

Summary
On the one hand, Wittgenstein's private language argument prevents discussion of Indirect and Direct Realism, but on the other hand, Wittgenstein writes that nobody can know another person's private experiences. That nobody can know another person's private experiences is at odds with the consequences of Direct Realism.

In the absence of any English speaker the word "tree" wouldn't exist, but the object currently referred to by the word "tree" would exist. — Michael

Exactly, that is what an Indirect Realist would say. The Direct Realist would have said "In the absence of any English speaker, the word "tree" wouldn't exist, but the tree would still exist in the world"

There's a very peculiar obsession with language in this discussion — Michael

As I believe in the ontology of Neutral Monism, where reality consists of elementary particles and elementary forces in space-time, the meaning of the word tree is fundamental to my philosophical understanding.

What could we call that thing...? If only there was a word for the thing in the world which I can make furniture out of, climb, get fruit from, paint the image of, sit under the shade of........ We really need a word for thing.......I suggest "tree(a)", what with the word "tree" already having been taken and all. — Isaac

This is the slightly mad bit.......That 'something that has caused me to perceive a "tree'?...........It's a tree........That's what a tree is. — Banno

Yes, "tree" is a good word. Within our language game we have the word "tree".

However, in the absence of any English speaker, the word "tree" would not exist, and "trees" would not exist in the world. In the absence of any English speakers, no one could discover in the world "trees". "Trees" only exist in the minds of speakers of the English language.

I perceive something that has been named "tree". As "trees" only exist in the mind, I am perceiving something in my mind that only exists in my mind, leading to a self-referential circularity.

This is the flaw in Searle's solution of the "intentionality of perception" to the epistemological problem of how we can gain knowledge of objects in the real world from private sense data, in that his solution leads to a similar self-referential circularity.

As an Indirect Realist I directly see a tree, I don't see a model of a tree. Searle wrote "The experience of pain does not have pain as an object because the experience of pain is identical with the pain". Similarly, the experience of seeing a tree does not have a tree as an object because the experience of seeing a tree is identical with the tree.



I have an innate belief in the law of causation, in that for every effect there is a cause, as well as the belief that the cause of an effect cannot be known just from knowing the effect. Combining these, my perceiving a "tree" must have been caused by something, yet I cannot know just from my perception what caused it.



Yet I need a name for the cause of my perception of a tree. My solution is to give the cause the same name as the effect. Therefore, if I see the colour green, I name its cause green. If I hear a grating noise, I name its cause a grating noise. If I smell an acrid smell, I name its cause an acrid smell. If I feel something silky, I name its cause silky. If I taste something bitter, I name its cause bitter. If I perceive a tree, I name its cause a tree.

"Trees" only exist within the language game. "Trees" exist within the mind as not only the name for what is perceived by the mind but also as the name of the unknown cause of that perception, ie "a tree" is the cause of perceiving "a tree".

If this is true, it's not a discovery about seeing but only about the grammar of 'see.' — green flag

Yes, which shows the importance of Wittgenstein's discussion of the language game in Philosophical Investigations.

I can build furniture out of fallen trees. Can I build furniture out of what you see in your dreams and hallucinations? — Isaac

You can build furniture out of the something in the world that has caused me to perceive a tree providing this had been a veridical experience, but not if a dream or an hallucination.

How could one ever be mistaken about what one sees? — Isaac

One can never be mistaken about what one sees. If you see a tree, it is absolutely certain that you have seen a tree. If you see a unicorn running through Central Park, it is absolutely certain you have seen a unicorn running through Central Park.

However, one can be mistaken in one's belief whether it was a veridical experience, a dream, an illusion, a film or an hallucination.

But can they see trees? — Isaac

According to Do blind people dream in visual images?, yes.

Instead, scientists have performed brain scans of people blind since birth while they are sleeping. What scientists have found is that these people have the same type of vision-related electrical activity in the brain during sleep as people with normal eyesight. Furthermore, people blind since birth move their eyes while asleep in a way that is coordinated with the vision-related electrical activity in the brain, just like people with normal eyesight. Therefore, it is highly likely that people blind since birth do indeed experience visual sensations while sleeping. They just don't know how to describe the sensations or even conceptually connect in any way these sensations with what sighted people describe as vision.

What about the tree that you climb? Is that a representation? — unenlightened

I know that I perceive something and I know that this something has the name "tree".

As I innately believe in the law of causation, in that every effect has a cause, I therefore believe that there is something that has caused me to perceive a "tree". I don't know what this something is, but I do believe it exists.

As language doesn't exist in the absence of sentient beings, the something in the world that we call a "tree" cannot be a "tree", as "trees" only exist within human language. "Tree" as a word in human language represents something else.

Therefore the "tree" that I climb as a word is a representation of something else but the something else that has caused me to perceive a "tree" isn't a representation.

So, for you, the eyes are not involved in seeing. A blind man can see? — Isaac

I see what you mean. I see the reason for your post. I see the relation between the eyes and what is seen. I see trees in my dreams. A fool cannot see beyond the end of their nose. I see trees in my hallucinations. I see myself on holiday. I see the light at the end of the tunnel. A blind man can see the truth. A blind man can see where they went wrong. A blind man can see the error of their ways.

Yes, a blind man can see.