I can tell you for a fact that I can see the colour of my carpet even though I'm not describing the colour of my carpet. — Michael

And I would say, I agree with you as long as I can ask you what color your carpet is, and you get it right.

But if you are incapable of routinely getting this right, I not to sure what sense can be made of saying "I still see the color of the carpet even though I am not describing it."

Even if they don't have words to describe the colours, they nonetheless see them, just as I can distinguish between a variety of different smells despite not having words for each individual kind of smell. — Michael

Not necessary.

If I have a color detecting machine where when I place a colored object in front of it, it will report the color in its display. However, one day it stops reporting the color on the display. We checking the display and is functioning fine. What sense is there in saying “Nevertheless the machine is still detecting the color even when we place it in front of the machine”

The same goes for a person looking at the colored balls.

I would say we don't (always). When we talk about colour we're not talking about objects but about sense data. — Michael

Exposing a brain to a particular wavelength of light to see how the brain or particles/waves of a brain reacts to the light does not necessitate the need to posit “sense data” to understand the science behind the phenomenon.

At first, yes. But then after a detailed scientific analysis (and assuming scientific realism is correct) we can extend it further to the cause being a collection of quarks, neutrons, and electrons, with the latter reflecting photons. — Michael

But now the metaphysical distinction breaks down between claim 1 and 2 for the indirect realist. Both reduced to talk of particles and waves. And to aid in this “talk” we use language to understand what we are taking about, particles and waves of the brain, and particles and waves of the tree. Interestingly, we by-pass the talk of “sense data”, and use everyday ordinary language of objects to set up some sort of correlation.

I didn’t say that I don’t know what is causing it. — Michael

But you only can say some empty generalization like “it is cause by some mind-independent object.” And that is not saying much of anything. Sort of like say, “What is causing your headache?” Response, “Everything” This is not so much an answer but more like an expression of exasperation.

1. I talk about external world objects
2. The nature of external world objects is given in my experience

Yes, both these claims require language to state, but they don’t mean the same thing. — Michael

Ok, let me know if my examples are appropriate for each:

1. I see the tree.

2. I experience “sense data” of a tree.

If it got this right, there are puzzling consequences of this view.

1. We learn the word “tree” to show a community of language users that we can pick out a correct object in this world. We find agreement in judgment. But the indirect realist says, “We cant’t quite know what is causing us to say such things.”

2. But I do know with great certainty about my “sense data”. Even if I don’t know what is causing my “sense data”, I know for certain what my “sense data” is. And what is that? In this case, “sense data” of a tree. But did you not say that you did not know what is causing your “sense data”, so you can’t say it is “of a tree”.

I think all that could be said by such a philosophical perspective is: I experience “sense data” of some unknown cause every time I experience something.

No specificity can be brought to the words used because of an unknown cause in the external world and an inaccessible experience the subject has.

Given such a consequence of such a view demonstrates the implausibility of such view. The view being “indirect realism”.

The problem is, however, the relationship between the social group and the world external to the social group, and whether the social group have indirect or direct knowledge of this external world. — RussellA

The social group is part of the world not external to it. This artificial distinction seems to be the cause of many philosophical problems. And the use of “external” seem somewhat ambiguous in this case. Is all that is meant by this is that there is a group of people and there is a group of trees? If so, you simple are distinguishing between two groups of objects.

That doesn't seem accurate. The epistemological problem of perception concerns the extent to which perception informs us about what the world is like. That doesn't seem to have anything to do with language at all. — Michael

This does not seem entirely accurate. Problems have to be articulated and understood. Solutions need to be articulated and understood. With what? Language.

f two people have headaches there is no way of comparing whether both of them are having the same type of pain. — Andrew4Handel

Some food for thought from Normal Malcolm's "The Privacy of Experience."

"Giving the location of one's sensation is not locating it in the space of physics or astronomy, but in a space of sensations that has one's own body as its frame of reference. If A locates a sensation in his space of sensation (e.g. in his right shoulder), and B locates a sensation in the corresponding place in B's space of sensation (e.g. in his right shoulder), then B's sensation is in the same place as A's sensation. If B located his sensation in a non-corresponding place (e.g. his right foot), then B's sensation would be in a different place from A's. Tis is how we use the expression "same place,"different place", in regard to sensations. Therefore, A and B are not giving different descriptions when each says, "in my shoulder."

One needs to keep in mind how we use "pain" from a first and third person perspective.

This is where it gets interesting. How divergent can someone get with their apparent language of colors where we begin to think that we are not talking about “colors”, or “seeing colors” anymore.

You put a red ball and a blue ball in front of me. I can see that one is red and one is blue. — Michael

But if you said, “I can see that one is green, and one is yellow”, can you be said to being seeing at all.

No, I'm saying so because I believe it to be a fact. And because it is a fact, what I say is true. — Michael

Why do you say it is a fact and it is true?

It is either a fact that private experiences exist or they don't. — Michael

You said this is a fact. Is that because you have testified to this, and thus, it is a fact because you say so?

I don't think facts depend on verifiability. It just either is or isn't the case that private experiences exist. — Michael

If you do not like verifiability, how does this fact establish its truth or falsity? One can make claims, but we do need to know how to establish whether it is a fact or not.

I may be absolutely certain of what I am seeing, whether a tree or snooker balls on a snooker table, but knowing the present effect doesn't allow me to know the preceding cause. — RussellA

I believe you are saying the following, “Conversely, most realists (specifically, indirect realists) hold that perceptions or sense data are caused by mind-independent objects. But this introduces the possibility of another kind of skepticism: since our understanding of causality is that the same effect can be produced by multiple causes, there is a lack of determinacy about what one is really perceiving…”

But this is a tough pill to swallow given the suppose cause and effect being discussed here:

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

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

Wow, I would not want to use that example to teach a kid what “cause and effect” means.

we have private experiences, so removing the colours inside the heads is to deny a fact. — Michael

But, in principle, this claim cannot be verified as either true or false, so we are not talking about facts here.

This reminds me of how Pythagoreans viewed numbers to such an extent that it could be viewed as a religion. Apparently, they had a prayer to something called a Tetractys (sometimes called the "Mystic Tetrad"):

“Bless us, divine number, thou who generated gods and men! O holy, holy Tetractys, thou that containest the root and source of the eternally flowing creation! For the divine number begins with the profound, pure unity until it comes to the holy four; then it begets the mother of all, the all-comprising, all-bounding, the first-born, the never-swerving, the never-tiring holy ten, the keyholder of all.”

Frege believed that number is real in the sense that it is quite independent of thought: 'thought content exists independently of thinking "in the same way", he says "that a pencil exists independently of grasping it. — Frege on Knowing the Third Realm, Tyler Burge

“In the same way” is the mystery. I can picture a hand separated in space from the hand. And I can picture the hand moving to grasp the pencil. But what am I picturing when thought content is separate from thinking? This is not a spacial relationship Maybe it is more like the relationship between a triangle and three sides, you can’t imagine one without the other. So, it is unlike a hand and pencil. Thus, they are not independent of each other.

and they're principles that, whilst independent of any particular mind, can only be grasped by the mind. — Wayfarer

In what sense is “principles independent of any particular mind”?

Nothing you say can convince me that I don't feel pain. — Michael

Unless we give you an anesthetic, right?

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. — RussellA

I once heard John Searle say something which I believe prevents one moving down the road to confusion.

Words do not refer, but human being use words to refer.

I think sometimes folk forget this which causes folk to think a word is magically "connected" to some object.

When I ask what the number 7 is, you will point to the number, 7, and say that is what it is. But '7' is a symbol. That is an invention and can be represented in many different symbols: VII, SEVEN. What is not invented, is the meaning of the symbol. And that is what we all agree on. — Wayfarer

If you asked me "what the number 7 is?", I may want a little more clarity on what you mean by this question. In different contexts, it could mean different things. If I did point to the symbol "7", maybe I was teaching a child how to count with mathematical symbols. Or maybe I had used that symbol to show how to add, subtract, multiple, or divide. Or, maybe I showed how numbers select out an individual in a soccer match. Or, maybe how it can be used to title a movie. All created by humans to give a dead sign "life." These symbols are created by humans, and humans give it a use which gives it a meaning.

When we talk about math, we say things like "I figured out the solution to the problem", "I constructed a proof to demonstrate such and such", or "I determine the equation for such a figure." It would be odd to say after every addition problem, "Wow I discovered '1+45=46', '25+75=100', '7+1000=1007', etc"

When we talk about "discovering meanings, ideas, eternal objects", we belittle the creative aspect of human intelligence. It gives this picture that human go into the room called "Platonic realm", find aisles of bins labeled "meanings", "idea", eternal objects" and select the one we like, call it a discovery, and share it with the world. I don't know about you, but that is not how I learn. I read books, listen to lectures, debate other people, ask questions, draw diagrams, make errors, test a hypothesis, conduct experiments, etc...in order to learn ideas or come up with new ideas.

If you want to argue that the feeling of being cold isn’t some essentially private mental phenomena but is reducible to brain activity then fine, but the same must also be said of seeing colours. Sight isn’t a uniquely special sense. They key point is that colour, like coldness and pain, aren’t properties of the external stimulus that trigger such experiences. — Michael

Additionally, if we want to call the "scientific description" of what we call "perception of color" as indirect because it depends on light, how light reflects off an object, atmospheric conditions present, the quality of air, the biological condition of the eye, the functioning of the brain, etc...OK. But, I don't think this is saying much more the what was iterated. There is no other "scientific description" to contrast the aforementioned "scientific description" in order to call it an indirect or direct "scientific description". I just rather called it a "scientific description". Lastly, I do not believe that this "scientific description" supports the indirect realist's metaphysical position, as I have argued in the last several posts. It can't in principle.

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

I have been arguing against the metaphysical positions of indirect realism. But that does not mean have been arguing for the metaphysical position of direct realism. I believe there is confusion being created on how this debate is using the words “direct/indirect”.

That said, I am puzzled by how you are characterizing the direct realist’s position with regard to your example of the person’s height as they walk away.

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?

Arguing that sometimes the differences can be explained with reference to the light source and viewing angle doesn't disprove that sometimes the differences must be explained with reference to something other than the light source and viewing angle. — Michael

But there is a difference between these two explanations, one metaphysical and one scientific. The scientific explanation has physical theory behind it. Verified countless times by a community of scientist. It has power to predict future occurrences and the power to construct our environment. All verifiable in the public realm.

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.

The fact that two people, fluent in English, describe the colours of the dress differently is evidence that the colours the dress appears to have to one are not the colours the dress appears to have to the other. — Michael

Why is it, do you think, that when shown the actual dress in normal lighting conditions the overwhelming majority of people will see that it's blue and black. What explains that extraordinary convergence? — Isaac

es, and different private experiences are the best explanation for the different responses. — Michael

I set up the following experiment: I put a car in a garage. And ask a group of people, one at a time, please go into this garage, look at the car and let me know what color you think the car is when you come back out. After this experiment, I collect the results and find that different people are reporting the car has different colors.

The indirect realist may want to posit "sense data" as the explanation for the difference between people reporting different colors, and claim it the best explanation. Unfortunately, I would have to break the news to the indirect realist that this is an unnecessary explanation. The car was painted with a pigment called ChromaFlair. When the paint is applied, it changes color depending on the light source and viewing angle. In this example, this was intentionally done, and I am sure this can happen un-intentionally too.

At the very least, the indisputable (to me) reality of my first person experience is proof enough (to me) that me seeing red and me saying “I see red” are completely different things. — Michael

However, I think you would agree that you can't say to me that "I actually see a blue object when I say "I see red object." This make no sense.

This is a position that I believe is refuted by our scientific understanding of the world and perception. Colour is "in the head", not in apples (or light). — Michael

Let’s try a little thought experiment showing the relationship between language, experience, and science.

Individual A and B live in a world where there are two colors, red and blue. In their communities, when they were children, they learned the words “blue”, and “red” from the elders. The elder would point to a blue object and utter “blue”, and the same for a red object. After showing multiple different objects, some blue and some red, Individual A and B demonstrated to the community they were able to judge colors the same as their elders by using the words “red” and “blue” at the correct times.

On day a scientist comes along and wonders what is going on inside the brain when one sees red and blue. So, he decided to examine the brain by hooking up a test subject with electrodes to determine which neurons are “firing” when exposed to a blue object and a red object. Individual A decides to go first. The scientist finds an object that the community agrees is a blue object. Next, the scientist connects Individual A to the electrodes to measure Individual A’s neural response. Upon exposure of the blue object, neuron cluster 99 lights up in the brain. Individual A confirms to the scientist that they see a blue object by saying “blue”. Additionally, the scientist confirms the light reaching the subject is of the scientifically correct wavelength. The same routine is repeated with a red object, and this time neuron cluster 11 lights up in the brain. Individual A confirms to the scientist that they see a red object by saying “red”. Next, Individual B is connected to the electrodes. However, when Individual B is exposed to a blue object, neuron cluster 11 lights up in his brain. But Individual B still confirms that they see a blue object, by saying “blue”. Conversely, when exposed to a red object, neuron cluster 99 lights up. But Individual B still confirms that they see a red object by saying “red”.

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. Specifically, for A cluster 99 lights up when exposed to blue, but for B cluster 99 lights up for red. And, for B cluster 11 lights up for blue, but for A cluster 11 lights up for red. 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.”

And so trying to say that language entails that we don't have private experiences — Michael

It is not that we don't have private experience but the language to articulate, like we do in the public sphere.

It has nothing to do with grammar. Experience isn't language. I can be an illiterate, deafblind mute, and yet still feel pain. — Michael

Animals get around the world without language, and they certainly are experiencing the world.

But humans use language to understand and communicate what is going on in their experience. So, sometimes what we say makes senses and sometimes it does not.

This discussion is trying to get agreement on this distinction.

We may not succeed, but we can try.

But we have private experiences, so removing the colours inside the heads is to deny a fact. — Michael

More like a grammatical fiction.

So it is OK to remove it.

We will all do just fine with our communication and understanding.

I like the picture, although to be consistent with indirect realism and to prevent any real-word bias, it would be best not to colour the circle in the middle, and to invent a new word to replace the use of "blue". — Michael

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. — RussellA

Better yet, to be consistent with Wittgenstein's view of “private language” one should remove the colors inside the heads of the figures. There is no private language to articulate this. And maybe there is nothing there like the beetle. All we have is the public object in which we call “blue”. There is agreement in judgement and use, thus, a form of life.

Do you have a response for people who do not take Wittgenstein's writings as gospel? — Art48

Yes, there is an alternative to praying at the altar of Plato, it is appreciating human’s incredible ability to create a form of life like mathematics.

The Pythagoreans were shocked to discover that the square root of 2 was irrational.It is an eternal fact that the square root of 2 cannot be expressed as a ratio of two whole numbers. That fact was true before the Pythagoreans discovered it and it will be true for all eternity. You seemed to be taking the Mathemetical Formalism route, which is a minority position among working mathematicians, most of whom accept Mathematical Platonism. — Art48

From Wittgenstein's "Remarks on the Foundation of Mathematic"

I 168, "The mathematician is aninventor, not a discoverer."

II 2 "But the mathematician is not a discoverer: he is aninventor."

II 38 "From the fact, however, that we have an employment for a kind of numeral which, as it were, gives the number of the members of an infinite series, it does not follow that it also makes some kind of sense to speak of the number of the concept 'infinite series'; that we have here some kind of employment for something like a numeral. For there's no grammatical technique suggesting employment of such an expression. For I can of course form the expression: "class all classes which are equinumerous with the class 'infinite series'" (as also: "class of all angels that can get on to a needlepoint") but this expression is empty so long as there is no employment for it. Such an employment is not: yet to be discovered, but: still to be invented."

V 11 "If you want to know more about the series, you have, so to speak, to get into another dimension (as it were from the line into a surrounding plane).-But then isn't the plane there, just like the line, and merely something to be explored, if one want to know what the facts are? No, the mathematics of this further dimension has to be invented just as much as any mathematics."

From Wittgenstein's Lectures on the foundations of Mathematic

"One talks of mathematical discoveries. I shall try again and again to show that what is called a mathematical discovery had better be called a mathematical invention. In some of the cases to which I point, you perhaps be inclined to say, "Yes they had better be calledinventions"; in other cases you may perhaps be inclined to say, "Well, it is difficult to say whether in this case something has been discovered or invented."

Wittgenstein's position is an outcomes of his later views on language and meaning, exploring how these symbols become "alive with meaning." For him, Platonic views of mathematics lack utility due to offering no explanatory power and leading to confusion.

We are truly naive realists if we believe that the way we experience and understand the world to be is exactly the way it really is independently of us. — Janus

I do not understand why some do not see or feel the emptiness of this description. The tone reminds me of negative theology, let us get to “Reality” by saying what it is not. But we never can get there, and they come up with equally empty slogans like if only we can get a “view from no where” or if we only can get “outside ourselves”. This move seems so innocent to use words that we are so familiar with yet are used in such unfamiliar ways.

But the indirect realist will say, “Wink, wink you get what we are saying.”

Yep, pure nonsense!

Would not basic arithmetical facts be true in all possible worlds? — Wayfarer

Interesting question. There is a lot to unravel here when using terms like "facts", "true", and "possible worlds" which will lead to much confusion.

1. What is an "arithmetical fact"? That we use a human invented symbolism like "2+2=4" and that this has rules of use, and has application in our world. OK. Or, do you mean "2+2=4" is a fact because it corresponds to some eternal idea. I reject this later position as metaphysical nonsense.

2. What make "arithmetical facts" true? That we use these human invented symbolisms like "2+2=4", we agree on the use, we agree on judging correctness. Ok. Or, do you mean "2+2=4"is true because it corresponds correctly to some eternal idea. I reject this later position as metaphysical nonsense. (As Wittgenstein says in PI 241"So you are saying that human agreement decided what is true and what is false?- It is what human beings say that is true and false; and they agree in the language they use. This is not agreement in opinions but in form of life."

3. Lastly, what to make of "true in all possible worlds"? First, I like what Saul Kripke said in N&N, "In the present monograph I argued against the misuses of the concept that regard possible worlds as something like distant planets, like our own surroundings but somehow existing in a different dimension, or lead to spurious problems of 'transworld identification." and "'Possible worlds' are stipulated, not discovered by powerful telescopes." Are you thinking this very thing by discussing other sentient being across the universe? Second, is it not hard to imagine a fictitious natural history where human do not have this symbolism, its use, its general agreement in judgment? If so, it would not be "true in all possible worlds".

"'To be practical, mathematics must tells us facts.'-But do these facts have to be, the mathematical facts?-But why should not mathematics, instead of 'teaching us facts', create the forms of what we call facts?" From Remarks on the Foundation of Mathematics, Wittgenstein.

It is a big step and probably the cause of much discussion in this thread. That 2+2=4 is eternal is one thing. — Art48

atever word someone wants to use), it's difficult to see how it could go out of existence or cease to be. — Art48

Let us see if we can provide a clearer path to seeing one’s way out of this conceptual muddle. I will use the “2+2=4” example.

1. We needs to recognize that humans invented the symbolism of “2+2=4”. Other symbolism could be used, and I am sure other humans have used different symbolism.

2. What makes these symbolisms the same is how they are used by humans. It is not that they refer to the same eternal objects.

3. “2+2=4” symbolism will cease to exist if there are no more humans using these symbols for any purpose. In fact, they will cease being symbols.

4. But one could say, even if there are no more human around, there could be two trees, etc. Yes, but there is not a tree and another tree, and “two-ness”, just a tree and another tree.

5. Last step, let us imagine we have no symbolism, nor anything else in the universe to count. What is left to articulate? Remember, humans do not exist, our symbolism does not exist, and the physical universe does not exist.

I would say this is easier or as easy “to see” as adding “Mindscape”/“Platonic realms”. And if we value parsimony, dropping “Mindscape/Platonic realms” would be wise.

So my argument is that they're real, because they're the same for all who think, but they're not strictly speaking existent. — Wayfarer

And it would be unreal if they’re different for all who think? But this would just be different ideas. Or, someone is thinking the same thing but the idea is different compared to someone else thinking the same thing? This does not make sense. Austin said the following about “real”, “Real, is also a word whose negative use “wears the trousers” (a trouser-word)”

But that is a reification - there is no literal 'realm of natural numbers', although it is conceptually real. — Wayfarer

Now I am curious, what is an example of something that is conceptually unreal?

Colours and smells are not mind-independent properties of objects but are products of brain activity that result from (usually) external stimulation. — Michael

This seems problematic to say. Let take a simple scientific definition of color. “Color is that portion of the visible spectrum of light that is reflected back from a surface. The amount of light that a surface reflects or absorbs determines its color.” Notice in this definition there is no appeal to mind or brain. Light is not being produces by the brain/mind, but is independently being produce outside the brain/mind.

What occurs inside the brain, when stimulated by a particular color of light can as well be studied. But scientists don’t study the brain by opening it up to find “colored objects” dancing around.

As for what occurs in the mind when stimulated by a particular color of light, not sure where to begin to make sense of this claim, like how does the physical interact with non-physical. I think we are probably in the realm of grammatical fictions where the word “color” mistakenly is thought to name a object within the mind.