In any event, it seems wrong to say that language would be the limit of our world. — Count Timothy von Icarus

:up:

'what two-dimensional surface do you think the purportedly two-dimensional image of our visual field is projected onto"? — Janus

When we look at the world, we initially see a two-dimensional image. I am not aware of any two-dimensional surface that this two-dimensional image is projected onto.

I looked into this further, and it seems to me Kant's Category of Cause is a concept to be applied to the external world events as cause and effect.  It is not to do with perceptions or the mental principles of reasoning. I still think the process of reasoning coming to judgements activated by intuitions, perceptions or thoughts is operated by Logic. — Corvus

I am making use of Daniel Bonevac's Video Kant's Categories.

Reason doesn't create logic, rather, what we reason has been determined by the prior logical structure of the brain

The brain must have a physical structure that is logically ordered in order to make logical sense of its experiences of the world. IE, the innate ability of the brain to process such logical functions as quantity, quality, relation and modality. In other words, Kant's Categories, aka The Pure Concepts of the Understanding.

For example, in our terms, Relation includes causality, and Quantity includes the Universal Quantifier ∀ and the Existential Quantifier ∃.

In Kant's terms, there are certain a priori synthetic principles necessary in order to make logical sense of experiences of the world . These innate a priori synthetic principles are prior to Reasoning about the phenomena of experiences through the Sensibilities. It is not the case that our reasoning is logical, rather it is the case that our reasoning has been determined by an innate a priori structure that is inherently logical, one possible consequence of the principle of Enactivism.

Our understanding of the world must be limited by what we are able to know of the world and what we can know of the world is limited by the innate structure of the brain. Taking vision as typifying the five senses, the human eye can detect wavelengths from 380 to 700 nm, which is only about 0.0035% of the total electromagnetic spectrum . In addition, understanding is also limited by the physical structure of the brain. As no amount of patient explanation by a scientist to a cat will enable the cat to understand the nature of quantum mechanics, by analogy, no amount of patient explanation by a super-intelligent alien to a human will enable the human to understand the true nature of quantum mechanics.

Kant is in effect saying that Chomsky's Innatism is a more sensible approach than Skinner's Behaviourism.

Superficially true, but insufficient to explain empirical discovery by a solitary subject. — Mww

As a solitary subject in a strange land, what would your intuition of the meaning of "ngoe" be ?

.Hume's principle of constant conjunction...............has more to do with the relation of cause and effect than to perception and cognition — Mww

From the IEP article on David Hume: Causation
Whenever we find A, we also find B, and we have a certainty that this conjunction will continue to happen.

If every time I see a particular object and hear someone say "Eiffel Tower", there is a good chance, though not absolute, that the name of this particular object is "The Eiffel Tower".

In a sense, the object does cause someone to say "The Eiffel Tower", in that there is a causal link between the object and the name.

But you just said the name is given by a relevant community, and if “tree” is that name for an object looked upon in the world by yours…..how can it be unique to you? — Mww

The Icelander and Ghanaian can agree with the Communal definition of tree as "a woody perennial plant, typically having a single stem or trunk growing to a considerable height and bearing lateral branches at some distance from the ground".

However, each will have their own unique understanding of what trees are based on their very different lifetime experiences.

No. I knew instead what "a thought of a cup" would mean in the context of our discussion. When I think about a cup I'm doing something, but no "thought of a cup" exists. — Ciceronianus

It is only possible for you to write that "but no "thought of a cup" exists" if you already know what the thought of a cup is.

IE, I can only say that that building over there is not the Eiffel Tower if I already know what the Eiffel Tower looks like.

Similarly, you can only say that the thought of a cup doesn't exist if you already know what the thought of a cup is.

It is never the case we think with language, or by means of it. — Mww

I agree. I have a pain in my left hand whose exact nature is inexpressible in language. The fact that I cannot express in language the exact pain does not mean that there is no pain. As Wittgenstein himself wrote in PI 293 of Philosophical Investigations: "The thing in the box has no place in the language-game at all"

We think, and name that which is thought about, the object of thought, cup. — Mww

We look at the world and see an object that has been given a name by the Community within which we live.

Both the object and name are physical things that exist in the world, and we link the object and the name through Hume's principle of constant conjunction.

The name doesn't describe the object, but is linked with the object through Hume's principle of constant conjunction.

IE if every time I saw the Eiffel Tower and at the same time heard the name Eiffel Tower, I would begin associate the name Eiffel Tower with the object Eiffel Tower

As a name is only linked with a thought of an object by Hume's principle of constant conjunction, the one can exist independently of the other. IE, one can have the thought of an object independently of any name it may or may not have been given.

MANY years ago, by sheer accident I put a chainsaw into my left foot. — Mww

Many years ago, I had a garden fork go though my right foot, so I do have an idea of what you experienced.

That every single word ever, and by association every single combination of them into a whole other than the words themselves, being at the time of its instantiation a mere invention, is for that very reason entirely private? — Mww

Yes, for example what I understand by the word "tree" is unique to me, as no one else has had the same life experiences. IE, the meaning of "tree" for an Icelander can only be different to the meaning of "tree" for a Ghanaian.

It may do well to note, in addition, as long as we’re “making a case for transcendental idealism”, that since it is merely the thought “cup”, there is already the experience of that particular object by the same subject to which the thought belongs, for otherwise the subject would’ve not had the authority to represent it by name. — Mww

How can a thought be named ?

Is it the case that we have the thought of a cup and then name it, or is Wittgenstein correct
in his belief that we cannot think without language. He wrote in the Tractatus para 5.62: “the limits of my language mean the limits of my world.”

If Wittgenstein is correct, then the mere act of writing "the thought of a cup" presupposes the thought of a cup.

2. It is awkward to speak about things-in-themselves; — Bob Ross

"Awkward" in (2) was used somewhat sardonically; "impossible" would presumably be more accurate. — Banno

Wittgenstein in para 293 of Philosophical Investigations makes a strong case that we can speak about things-in-themselves.

He writes:
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. 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.

A word such as "red" does not describe a thing-in-itself, but replaces the thing-in-itself, allowing us to sensibly talk about things-in-themselves.

IE, in Wittgenstein's terms, there is an equivalence between the words "red", as in "I see a red post-box", and "beetle".

Have you managed to find Sense and Sensibilia? — Banno

Thanks, I have downloaded a copy and will read it. :up:

===============================================================================

You don't see the cup as having depth? Odd. — Banno

Are you using the word "see" metaphorically?

In my field of vision, I can only see the surface of any object facing me, which appears two-dimensional, but in my mind I can imagine the three-dimensional space the object occupies.

===============================================================================

It's a very odd thing for RussellA to say - even folk with one eye have depth perception. — Banno

I didn't actually say that, but even if I had, I would be in good company.

The BBC Science Focus notes that:
For example, we know the size of things from memory, so if an object looks smaller than expected we know it’s further away.

The atom used to be the stand-in for 'simple' in that it was 'indivisible', not composed of parts. Regrettably, nature did not oblige, as it turns out atoms are far from simple. — Wayfarer

:up:

Are you not familiar with the depth perception due to parallax? Is there really any such things as a two-dimensional image? Even lines and the paper they are on are really three-dimensional. — Janus

Parallax can be used to determine the distance of an object, as nearby objects show a larger parallax than farther objects, but it doesn't allow us to see the back of a three-dimensional object.

What is parallax doing? Is it giving us information about the distance of an object from us or is it giving us information about the three-dimensional space that the object occupies?

Sorry, but I don't think there is such a thing as a "thought of a cup." — Ciceronianus

In order to write the sentence "Sorry, but I don't think there is such a thing as a "thought of a cup."" you must have had the thought of a cup.

I am still saying that, just the red patch colour visual perception would be more meaningful than the scientific instrument reading of the red patch emission of 700nm to the most ordinary people — Corvus

Yes, as you say, most ordinary people can understand Naïve Realism.

Even if the supposed Atom images are seen in the microscope, how do you know they are atoms? — Corvus

Yes, even the atom is a representation of something deeper, which is why my position is that of Indirect Realism. As the IEP article on Objects of Perception writes:
The indirect realist agrees that the coffee cup exists independently of me. However, through perception I do not directly engage with this cup; there is a perceptual intermediary that comes between it and me. Ordinarily I see myself via an image in a mirror, or a football match via an image on the TV screen. The indirect realist claim is that all perception is mediated in something like this way. When looking at an everyday object it is not that object that we directly see, but rather, a perceptual intermediary. This intermediary has been given various names, depending on the particular version of indirect realism in question, including “sense datum, ” “sensum,” “idea,” “sensibilium,” “percept” and “appearance.”

I think that what you call Indirect and Direct Realism reflect a pseudo-problem.........................We see a cup made up of atoms, then. Does that make it any less a cup? — Ciceronianus

As Bertrand Russell in The Problems of Philosophy wrote:"But the notion of being 'in' the mind is ambiguous. We speak of bearing a person in mind, not meaning that the person is in our minds, but that a thought of him is in our minds."

In the expression "we see a cup made up of atoms", the underlying problem is the inherent ambiguities within language. It is not a cup that is the object of consciousness, but rather the thought of a cup that is the object of consciousness. There is no cup in our minds, only the thought of a cup.

There is the act of apprehending a cup in a mind-independent world, but this does not mean that there is a cup in a mind-independent world that is being apprehended.

The question as to whether cups exist or not in a mind-independent world is certainly not a pseudo-problem, as it is crucial to our understanding of the nature of reality.

Strictly speaking, wouldn't it be the instruments (invented and calibrated for their own convenience by humans) which tells the wave length of 700nm emission, rather than science? — Corvus

Difficult to escape from a metaphorical use of language. I am using "science" is a figure of speech that includes the instruments of science.

See, could be, not necessarily or for definite. "could be" sounds a negativity in disguise here — Corvus

Wholes have parts, which in turn have parts, which in turn have parts. But sooner or later one assumes there are parts which have no parts, ie, simples. In contemporary mereology, a simple is any thing that has no proper parts. Sometimes the term "atom" is used, although in recent years the term "simple" has become the standard.(Wikipedia - Simple (philosophy)). It may be that fundamental forces and fundamental particles are simples, but science may discover it to be something else altogether.

Not sure, if science has to be consulted for that assurance. Wouldn't common sense or intuition do? And we don't really care about a set of atoms unless for some peculiar reason. To me atoms are just an abstract concept, that doesn't exist in the real world. Or if it did, it has nothing to do with me, or daily life. — Corvus

Science can tell us things that intuition cannot, such as when we perceive a red object, such as a post-box, the object may have emitted a wavelength of 700nm.

I only mentioned science to try to distinguish between a subjective mind and objective world. Coming from a position of mereological nihilism, my belief is that the cup as appearance does exist in the mind but the cup as thing-in-itself doesn't exist in a world independent of any mind.

In a sense, "atoms" are a convenient figure of speech for mereological simples, whatever they may be, but could be fundamental forces and fundamental particles existing in time and space.

So you might say Kant says that there are two cups?  That is absurd...............Logic is the engine of how rationality, intuition, perception, understanding and judgement works. — Corvus

When I look at a cup, in my mind is a two-dimensional appearance, but science tells me that what I am actually looking at is a set of atoms in a three-dimensional space.

In one sense there are two cups, the cup as it exists as a two-dimensional appearance in my mind and the cup as it exists as a three-dimensional set of atoms, both of which are very different. But in another sense, there is only one cup, the cup as a thing-in-itself in the world as the cause of the cup as an appearance in my mind.

What is crucial is a logical connection between the thing-in-itself in the world and the appearance in the mind, and this connection is what Kant understands as the Category of Cause. Kant's Category of Cause is what ensures that there is only one cup, even though the cup may exist in different forms, first as a set of atoms in three dimensional space in the world and then as a two-dimensional appearance in the mind.

Kant's Category of Cause is crucial to the viability of his Transcendental Idealism.

But when we talk about the cup, the pot, the cupboard, we are not talking about our private perception-of-cupboard, or the pot in itself, or one's mental image of a cupboard, but about the cup, cupboard and pot. — Banno

Both the Indirect and Direct Realist see a red cup, take it out of the cupboard, boil the kettle and make themselves a cup of tea.

However, the Indirect Realist takes into account the fact that science has told us that the cup we perceive as red is actually emitting a wavelength of 700nm. This causes them to question whether what they perceive as a red object is actually red. They then begin to question the relation between the appearance of an object and the object as a thing-in-itself.

However, Direct Realism turns a blind eye to scientific discoveries and continues to insist that when we perceive an object to be red it is actually red.

The Direct Realist refuses to address Kant's concerns about the ontological nature of objects in the world, and limit themselves to Wittgensteinian Linguistic Idealism, whereby language games are founded on hinge propositions, such as "I see a red cup". Such hinge propositions remain true regardless of the ontological reality of the world .

Part of the problem is that whilst the Direct Realist wilfully ignores Kantian concerns with the ontological nature of reality in favour of Linguistic Idealism, the Indirect Realist is willing to take into account not only Kant's ontological concerns but also Wittgenstein's Linguistic Idealism, acknowledging that language is needed to talk about the non-linguistic.

I think this is a question only if we assume that we or our "minds" are separate from (outside) of the world. That's not an assumption I think we should make. We are a part of the world, not outside it. The chair is a part of the world as well. The chair isn't part of us. We aren't a part of the chair. We are a part of the world. The world isn't inside us, as we're a part of it. We have certain characteristics as human beings. We interact with the world as human beings do. We see as human beings do, hear as they do, etc. There's nothing surprising about this, and it doesn't establish in itself that we can't know what it is we encounter or interact with. — Ciceronianus

As an Indirect Realist, I agree with your paragraph, as would a Direct Realist, but this does not address the topic of the thread "A Case for Transcendental Idealism". In other words, "A case for Indirect Realism".

Both an Indirect and Direct Realist would agree that both us and the chair are part of the same world, but they would disagree as to the nature of this world

You inferred before your support for Direct Realism as opposed to Indirect Realism
To Kant, though, is reserved the claim that there is, e.g., some thing which I call a chair and sit on all the time, which although it is in all respects a chair as I understand a chair to be and I use it as such, cannot be known.

I am persuaded by Bertrand Russell's support for Indirect Realism as he sets it out in the beginning of his book "The Problems of Philosophy"

My question is, how does the Direct Realist answer Indirect Realism's objections to Direct Realism?

. And, if we can't know what "things in themselves" really are, what possible difference would it make? — Ciceronianus

This morning, when making a cup of tea, it didn't pass my mind whether the cup was an appearance or a thing-in-itself. But this is a Philosophy Forum, where such considerations are of interest.

Neither you nor I have minds lurking within us, separate from the rest of us. We think as part of our interaction with the rest of the world. Language as well is a result of that interaction, as are the definitions arrived at in the use of language. — Ciceronianus

I believe in Enactivism, the philosophy of mind that emphasizes the interactions between mind, body, and the environment (Wikipedia - Enactivism). I agree with Dewey's cultural naturalism, where philosophy should be seen as an activity undertaken by inter-dependent organisms-in-environments (SEP - John Dewey)

We agree that we as humans interact with the rest of the world, but the central question remains unanswered, where exactly is this world that we interact with?

For example, this question was never addressed by Wittgenstein in Philosophical Investigations.

There is certainly a world that we interact with, but is this the world of the Direct or Indirect Realist.

Is it the case as the Direct Realist believes that the world as we perceive it exists independently of our perception of it but exactly as we perceive it, or is it the case as the Indirect Realist believes that the world as we perceive it only exists as a representation of something that exists outside our perception of it.

Yes, there is a chair in the world that we interact with, but does this world of chairs exist in our minds or outside our minds?

It's strange to think of the phenomena/noumena distiction in relation to one's own body parts. Is there a nose-in-itself vs the phenomena of it? — Gregory

After an amputation, some people experience pain in the part of the limb that’s no longer there. This sensation is phantom limb pain. The pain is real. The phantom part refers to the location of the pain: the missing limb or part of the limb (such as fingers or toes) (Leveland Clinic - Phantom Limb Pain)

Moore famously put the point into dramatic relief with his 1939 essay Proof of an External World, in which he gave a common sense argument against scepticism by raising his right hand and saying "here is one hand," and then raising his left and saying "and here is another" (Wikipedia - Here is one hand)

Who is to say that Moore hadn't had both his hands amputated after an accident, and only imagined his hands were still there?

Here's a small chance, a chink in the wall of Kant*. What if talk of the cup perceived and of the cup's ding an sich are talk of the very same thing? Perhaps there is just one cup? — Banno

Given your position as a Direct Realist, and assuming Direct Realism, when we look at an object and perceive the colour red, science may tell us that the object has emitted a wavelength of 700nm

How can the Direct Realist justify that a perception of red in the mind and a wavelength of 700nm in the world are the very same thing?

To my understanding Kant became a dualist because of the arguments by Hume that physical "laws" cant be known — Gregory

Yes, empirical knowledge is insufficient by itself for understanding. In today's terms, Innatism is also needed.

Also i'd like to say that if a positivist says he is not an idealist, why won't he just call himself a materialist then? — Gregory

If Positivism is the philosophical theory that holds that the only true knowledge is scientific knowledge, based on data and experience, then Kant was not a Positivist.

I would say there is no "thing" called a concept floating about in a thing called a "mind." — Ciceronianus

We both have the concept of a "thing" in our minds. If our concept of "thing" doesn't exist in our minds, then where does it exist?

Concepts and minds all exist in the same world as chairs — Ciceronianus

It seems that your position is that of Idealism.

First, you have inferred that the chair can be known:
To Kant, though, is reserved the claim that there is, e.g., some thing which I call a chair and sit on all the time, which although it is in all respects a chair as I understand a chair to be and I use it as such, cannot be known

Also, you have said that minds exist in the same world as chairs:
Concepts and minds all exist in the same world as chairs.

Kant was a philosophical Realist. From the Wikipedia article Philosophical Realism
Philosophical realism – usually not treated as a position of its own but as a stance towards other subject matters – is the view that a certain kind of thing (ranging widely from abstract objects like numbers to moral statements to the physical world itself) has mind-independent existence, i.e. that it exists even in the absence of any mind perceiving it or that its existence is not just a mere appearance in the eye of the beholder

From the Wikipedia article on Idealism
Idealism in philosophy, also known as philosophical idealism or metaphysical idealism, is the set of metaphysical perspectives asserting that, most fundamentally, reality is equivalent to mind, spirit, or consciousness; that reality is entirely a mental construct; or that ideas are the highest form of reality or have the greatest claim to being considered "real"

To Kant, though, is reserved the claim that there is, e.g., some thing which I call a chair and sit on all the time, which although it is in all respects a chair as I understand a chair to be and I use it as such, cannot be known. — Ciceronianus

We all have the concept of a chair in our minds, and we only know what a chair is because in our minds is the concept of a chair.

It is true that you can point to something in the world that corresponds with your concept of a chair, but you cannot point to something in the world that is your concept of a chair. IE, concepts exist in the mind, not in a world outside the mind.

Kant is not saying that we have no concept of chair in our minds, but he is saying, as would an Indirect Realist, that concepts only exist in the mind and not in a world outside the mind.

@Bob Ross @J

For every effect there is a cause
We know that one of Kant's Categories was the Category of Cause. There are many passages in the Fourth Paralogism, where the thing-in-itself is declared to be the cause of appearances. For Kant, Knowledge is both formal, a priori through the Category of Cause, and material, a posteriori given empirically through sensations.

I agree with @J who wrote "surely Kant didn't "deny that things exist outside the mind" -- he merely sought to discover the limits of our knowledge of them".

Common sense tells us for every effect there has been a prior cause. EG, a snooker ball on a snooker table doesn't spontaneously move until hit by either a snooker cue or another snooker ball.

Reason tells us that the same effect may have different causes, eg, a broken window could have been caused by either a ball or a bird. Reason also tells us that two different effects have two different causes, eg, perceiving the colour red may be caused by an object emitting a wavelength of 700nm and perceiving the colour green may be caused by an object emitting a wavelength of 530nm.

The perception of the colour of objects in the world
Science tells us if an object emits a wavelength between 620nm and 750nm, all things being equal, we perceive the colour red, and if an object emits a wavelength of between 495nm and 570nm, all things being equal, we perceive the colour green.

For the Indirect Realist, the effect, eg, the perception of the colour red, can have a different kind of existence to its cause, eg, an object emitting a wavelength of 700nm. For the Direct Realist, the effect, eg, the perception of the colour red, has the same kind of existence as its cause, eg, an object emitting the colour red.

For the Indirect Realist, in the absence of any observer, an object emits a wavelength of 700nm. For the Direct Realist, in the absence of any observer, an object emits the colour red.

Does colour exist outside a person's perception of it
When we look at one object emitting a wavelength of 640nm and another object emitting a wavelength of 730nm, all things being equal, we perceive that they are similar in some way, ie, both red. But when we look at one object emitting a wavelength of 640nm and another object emitting a wavelength of 530nm, we perceive that they are different in some way, ie, one is red and the other is green.

The Indirect Realist attributes this to how the wavelengths are perceived in the mind.

Question to Direct Realists
My question to the Direct Realist is, in the absence of anyone perceiving such objects, whilst agreeing that the wavelengths of 640nm and 530nm are different, in what way is it possible for the wavelengths of 640nm and 730nm to be similar?

Whatever the things are in-themselves is entirely impossible to know. — Bob Ross

This is the position of the Indirect Realist. The Direct Realist would say that things-in-themselves are possible to know, as the world we see around us is the real world itself, where things in the world are perceived immediately or directly rather than inferred on the basis of perceptual evidence.

We can talk about things-in-themselves even if we don't know what they are

There are many passages in the Fourth Paralogism of Kant's Critique of Pure Reason where the thing-in-itself is declared to be the cause of appearances.

For example in A199/B244: Now if it is a necessary law of our sensibility, thus a formal condition of all perceptions, that the preceding time necessarily determines the following time (in that I cannot arrive at the following time except by passing through the preceding one), then it is also an indispensable law of the empirical representation of the temporal series that the appearances of the past time determine every existence in the following time, and that these, as occurrences, do not take place except insofar as the former determine their existence in time, i.e., establish it in accordance with a rule. For only in the appearances can we empirically cognize this continuity in the connection of times.

When we perceive the colour red, there is the appearance of the colour red in our sensibilities, which we can reason to have been caused by a particular thing-in-itself. When we perceive the colour green, there is the appearance of the colour green in our sensibilities, which we can reason to have been caused by a different particular thing-in-itself.

It is true that we cannot know the thing-in-itself that has caused our perception of the colour red, but we can reason that it is different to the thing-in-itself that has caused our perception of the colour green.

We may not know what the thing-in-itself that caused our perception of the colour red, but we can reason that it exists, and we can reason that it is a different thing-in-itself to what caused our perception of the colour green. We can name the unknown thing-in-itself that caused our perception of the colour red as R, and and we can name the unknown thing-in-itself that caused our perception of the colour green as G.

The names R and G are not descriptions, as a description of an unknown thing-in-itself would be impossible, but they are, as Wittgenstein says in Philosophical Investigations, replacements for the unknown thing-in-itself. As with the Beetle in the Box, PI 293, this allows us to talk about unknown things-in-themselves.

For the Indirect Realist, thing-in-themselves may be impossible to know, but we can talk about them.

There is experience, therefore something exists. — Bob Ross

As an Indirect Realist, I agree.

As both good philosophy and good science are founded on sound logic, your argument aiming at being logical is as much science as it is philosophy.

Odd, isn't it, that when some folk discover that the chair they are sitting on is composed of atoms, and is overwhelmingly space, they sometimes decide that therefore it's no longer really a chair. — Banno

It depends whether one is an Indirect or Direct Realist

My belief is in Indirect Realism, whereby our ideas of objects existing in a mind-independent world are interpretations of sensory input derived from a mind-independent world that is real. I also believe that Kant and @Bob Ross can be said to be Indirect Realists.

I am sure that your belief is in Direct Realism, whereby objects in a mind-independent world are perceived immediately or directly rather than inferred on the basis of perceptual evidence

Odd, isn't it, that millions of years ago even before there were folks, lakes and seas existed, even though there was no mind present at that time able to judge whether a large stretch of water was a lake or a sea.

Odd, isn't it, that millions of years ago even before there were folks, that the colour red existed, even though there was no mind present at that time able to judge a similarity in the wavelengths of 620nm to 750nm.

Odd, isn't it, that that millions of years ago even before there were folks, there were rocks that could function as either a table or chair, even though there was no mind present at the time able to judge whether the rock functioned as a table or chair.

As lakes, seas, the colour red, rocks, tables and chairs only exist as concepts in the mind and names in language and don't exist in a mind-independent world, they cannot be perceived immediately or directly in a mind-independent world as required by Direct Realism.

Direct Realism is invalid as one cannot perceive something immediately or directly in a mind-independent world if that something doesn't exist in a mind-independent world.

Yes, but not for scientific reasons. — Bob Ross

What non-scientific reasons are there to hold the view of perception that subjects do not experience the external world as it really is, but perceive it through the lens of a conceptual framework.

I am starting to embrace transcendental idealism, — Bob Ross

Am I right in thinking that your position is that of Indirect Realism, as described by the Wikipedia article Direct and Indirect Realism

Indirect realism is broadly equivalent to the scientific view of perception that subjects do not experience the external world as it really is, but perceive it through the lens of a conceptual framework.

When an object changes from existence to non-existence (the book on the table),  the property of the object changes from extension to non-extension. — Corvus

On the desk is a book. One could say that the book exists because the atoms that make it up exist in different locations, for example, atom A and atom B. One could also say that the desk exists because the atoms that make it up exist in different locations, for example, atom C and atom D.

The mind connects atom A and atom B as being part of the object book, and also connects atom C and atom D as being part of the object desk. Therefore, these objects, the book and the desk, exist in the mind.

But outside the mind, what connects atom A to atom B but not to atom C?

If there is nothing outside the mind that preferentially connects atom A to any other particular atom, then objects as we know them don't exist outside the mind.

Outside our minds, atoms exist but not objects (treating the "atom" as a figure of speech for something that does physically exist)

Objects as a concept in the mind don't exist outside the mind, meaning that we can perceive something as existing in the world that in fact doesn't exist in the world.

IE, we perceive something where in fact there is nothing.

You can perceive the essence of the Absolute Nothingness via Husserl's phenomenological method called Bracketing, which is to bracket the distracting details of the perception such as the book, existence, the table ...etc, and just concentrating on the subjective experience of Absolute Nothingness - i.e. {the non-existence} of the book at that moment of your perception. — Corvus

There seems to be a family resemblance between Bracketing and Nominalism.

Wikipedia - Bracketing (Phenomenolgy)
The preliminary step in the philosophical movement of phenomenology is describing an act of suspending judgment about the natural world to instead focus on analysis of experience.

Wikipedia - Nominalism
In metaphysics, nominalism is the view that universals and abstract objects do not actually exist other than being merely names or labels.

But the universe will contain no objects, — universeness

As a Nominalist, rather than a Platonic Realist, that's my present understanding of the universe today, in that there are no such things as objects in the world outside the mind. What we perceive as a book only exists in the mind. What exists in the world outside the mind are elementary particles and elementary forces existing in time and space.

Let's ignore language or communicating with others. Do you think it's possible for an existent to perceive 'nothing?' internally? — universeness

Or if there was a book on the desk this morning. You saw it there lying on the desk. But when you saw the desk when you returned home from the town after few hours of errands, it has gone. There is nothing on the desk....................At that moment, in your mind, you have the feeling or perception of "absolute nothingness" about the existence of the book. — Corvus

A book at one moment in time can only exist in one location. For example, in the morning, it exists on the desk. But in order for it to exist on the desk, it cannot exist anywhere other than on the desk, for example, under the desk or ten metres to the right of the desk.

As I perceive the book existing on the desk, at the same time, I also perceive the book as not existing under the desk.

Generalising, to be able to perceive something somewhere, I must be able to perceive nothing somewhere else.

What are the counterpart words for "car", "book" and "Coca Cola"? — Corvus

For Derrida, the meaning of a word derives from how it contrasts with other related words.

In this instance "car" contrasts with bicycle, train and pedestrian. "Book" contrasts with film, ebook and radio. "Coca Cola" contrasts with orange juice, Pepsi Cola and water.

From the Britannica article on Jacques Derrida
Building on theories of the Swiss linguist Ferdinand de Saussure, Derrida coined the term différance, meaning both a difference and an act of deferring, to characterize the way in which linguistic meaning is created rather than given. For Derrida as for Saussure, the meaning of a word is a function of the distinctive contrasts it displays with other, related meanings. Because each word depends for its meaning on the meanings of other words, it follows that the meaning of a word is never fully “present” to us, as it would be if meanings were the same as ideas or intentions; instead it is endlessly “deferred” in an infinitely long chain of meanings. Derrida expresses this idea by saying that meaning is created by the “play” of differences between words—a play that is “limitless,” “infinite,” and “indefinite.”

There is a table in front of me. On the left there is not a unicorn and on the right there is not something.

As there is no logical necessity that a word such as "unicorn" refers to a thing that exists outside of language, there is also no logical necessity that a word such as "something" also refers to a thing that exists outside of language.

Regarding the question "Why is there something rather than nothing?", as we know that "something" and "nothing" exist in language, but cannot know whether something and nothing exist outside of language, our reply can only be in terms of language and not in terms of what may or may not exist outside language.

Why is there something rather than nothing? — Ø implies everything

"Something" and "nothing" are words. As only words that are part of a pair (more or less) have any use in language - hot/cold, up/down, sense/nonsense, good/bad - the fact that a word exists in language assumes it has a counterpart - something/nothing. If a word had no counterpart, it wouldn't be part of language in the first place.

IE, the reason there is "something" is that it has the counterpart "nothing". In other words, as Derrida might have said "vive la différence".

Could you then please explain how the brain generates the mind? Please explain in detail how can the mental can emerge from the physical. — Corvus

If I could explain that, then I would be world famous.

I feel that self is a special perception (apperception of Kant's term), that looks inwards into the mind, whereas all the standard perceptions look outwards into the external world. — Corvus

But dragging the brain into the Epistemic discussion has been always the same - nothing much in essence and nothing really fruitful to add into the conclusion apart from just muddling up the points. — Corvus

The self is a special form of perception which looks inward into your mind, being conscious of all the mental events taking place in your mind. The self perception would be invisible or unknowable by all your outward perceptions. It can only be intuited via mediation or self introspection. In that sense, it is transcendental in nature. — Corvus

If I correctly understand your position:
1) You distinguish between standard perceptions looking outwards into the external world, and special perceptions that look inwards into the mind
2) Within the mind are both inward and outward looking perceptions
3) The mind is somehow generated by the brain
4) The self is known by inward perception, and the self knows both inward and outward perceptions.

As both inward and outward perceptions are part of the self, then one would expect that the outward perceptions would know the inward perceptions, as they are both part of the same self. Yet you say that the outward perceptions don't know the inward perceptions.

Kant's apperception is not a special kind of perception, but is a unity of apperception that applies to all perceptions, whether inwards or outward looking.

A common epistemological question is the relationship between the mind and brain, the relationship between the mental and the physical, in asking how can the mental emerge from the physical.

If the physical brain is excluded from the epistemological discussion, then Realism is also being excluded from the epistemological discussion, as, in Realism, a material substance such as the brain does exist outside the mind.

The discussion then reduces to that of Idealism, in that there is no material substance outside the mind, no physical brain outside the mind.

When you say "all the standard perceptions look outwards into the external world.", if epistemology has been reduced to Idealism, then the external world would exist in the mind, meaning that all perceptions look inwards into the mind. In that event, any distinction between inward and outward looking perceptions disappears, such that the self does then become available to Kant's unity of apperception.

However, Realism and the physical brain cannot be excluded from the epistemological discussion.

So it is not very fruitful to bring the brain into the epistemological discussion yet until the sciences made some real progress on explaining the hard problems. — Corvus

As you wrote: The mind has two sides, i.e. the inside (self) and outside (perceptions for the external world).

The relationship between the mind and body, and how the mind can emerge from a physical brain, is part of the epistemological debate. To say that the physical brain cannot be brought into the epistemological debate is to take the side of Idealism, thereby excluding the possibility of Realism.

The Direct Realist would say that our perceptions of the external world are directly of the external world, rather than inferred on the basis of perceptual evidence.

The Indirect Realist would say that our perceptions of the external world are not directly of an external world, but are directly of an internal representation in our mind of an external world. Such a representation may or may not directly correspond with the external world that is causing such representations

The Berkelian Idealist would say that the external world exists in the mind of God.

The Solipsist Idealist would say that the external world only exists in the mind of the perceiver.

The Realist would say that the external world exists independently of the mind. They are not Immaterialists, in that there is such as thing as material substance. They can be either a Monist, where there is only one fundamental substance, the mind/body, or a Dualist, where there are two fundamental substances, the mind and the body.

The idealist would say that there is no external world existing independently of any mind, and are Immaterialists in that there is no such thing as material substance

Personally, I am an Indirect Realist, Neutral Monist and Nominalist.