That’s awesome! I wish there were more tools like this. That said, the complexity of this material just confirms why I have avoided philosophy for the most part.

Well like everyone here I'm aware that Kant is a very difficult read, and there's a lot of material to cover. Honestly reading him is a slog. I think I've got some of the basic ideas of transcendental idealism but there are many sections that I haven't engaged with yet. Anyway, those free online editions are quite good, the Kindle edition in particular. I'll also add there there's an abridged edition, which I own, but which I admit I also haven't read. :yikes:

If it helps, the schematic Wayfarer linked includes, without any confusion, my understanding of hte first fifteen pages :)

I'm finding that as long as i read slowly, it really isn't that hard to grasp. The schematic above is helping my trust that intuition.

Thanks. it’s entirely my fault. I don’t really have the right disposition. But I love a good overview.

It's pretty damn rough to read. It's one a the very few cases in which I recommend secondary literature before reading the book, there's plenty of it.

But even with this secondary literature, there's a whole lot that is just hard to follow, because he is just way too technical. But of course, it has come excellent ideas.

That's a pretty cool map!

It's pretty damn rough to read. It's one a the very few cases in which I recommend secondary literature before reading the book, there's plenty of it. — Manuel

Any specific recommendations? I'm finding it very dense, but going slowly is giving me some confidence im my interpretations. I'd like to know if i'm just not getting it LOL

Mmm. It's not super, super easy, but, much easier than the Critique, Lucy Allais' Manifest Reality is sublime. Try that one out.

Then read his (Kant's) Prolegomena. After that, you could try other sources, or just struggle with the darn thing.

Or get yourself an @Mww, if they are up for sale. They can help a lot. :cool:

Thank you mate :) I shall look into those sources.

Hey, now!!! I’ll have you know, I’m cheap but I ain’t easy. (Grin)

Oh heavens.

If it were easy, it would be no fun. :cool:

Lucy Allais' Manifest Reality is sublime. — Manuel

Seems an exemplary book, thanks for the tip :clap:

Anytime! :cheer:

Please to note that thus far (beginning of Part One) Allias' interpretation is fully compatible with the one I offer in 'Mind-Created World'.

I think so too, she starts, iirc, speaking about how Kant is an empirical realist but also a transcendental idealist, that he is both and that there is no contradiction. You say something similar.

She'll go on to speak about how he would fit today under different analytic interpretations (realism vs. anti-realism, metaphysical vs. deflationary interpretations, etc.)

But the part I liked the best is the last 2 (maybe 3) chapters, which is what I've read many times.

Entire book 2. So, if you do agree with her, seems to me you have a decent theory in the works. :)

You can say what you like, but depending on the ground of the determinations by which you say anything at all, re: how you understand things in general, and in particular from transcendental philosophy, you cannot say “the window was broken by a thing-in-itself”. — Mww

It is interesting question why on seeing a broken window I instinctively believe that something broke it, even though I may never know exactly what. Why do I have a primitive belief that if something happens there must have been a reason? Why does my belief in cause and effect seem innate?

It is a matter of debate whether the Kant's Category of Causality applies only to Appearances or also to Things-in-Themselves.

First, Kant was not a Phenomenologist, in that he believed there are objects outside the mind and second, he made use of the Principle of Sufficient Reason, where any change in time of an object of experience must conform to causal law.

Kant does say in A20/B34 that an object may be understood in two ways, as an Appearance and as a Thing-in-Itself.
The effect of an object on the capacity for representation, insofar as we are affected by it, is sensation." That intuition which is related to the object through sensation is called empirical. The undetermined object of an empirical intuition is called appearance.

In numerous passages, Kant does describe the Appearance and Thing-in-Itself distinction, but it can be argued not as a distinction between two different objects but as two ways of considering the same object, inferring what is called the Dual Aspect View.

The Dual Aspect view of Kant, developed in the 1960's and 70's attempted to overcome the Phenomenalist problem with Affection, and argued that the Phenomenologists had mistakenly assumed that appearance and things-in-themselves are ontologically distinct kinds of objects.

Kant wrote in the Preface that the same object can be considered as it appears to us or as it is in itself.
The same objects can be considered from two different sides, on the one side as objects of the senses and the understanding for experience, and on the other side as objects that are merely thought at most for isolated reason striving beyond the bounds of experience. (Bxviii–Bxix, note) the reservation must well be noted that even if we cannot cognize these same objects as things in themselves, we are at least able to think of them as things in themselves. (Bxxvi)

There are passages in the Fourth Paralogism where the Thing-in-Itself is declared the cause of Appearance
A380 The transcendental object that grounds both outer appearances and inner intuition is neither matter nor a thinking being in itself, but rather an unknown ground of those appearances that supply us with our empirical concepts of the former as well as the latter.

Kant also writes in Prolegomena to any Future Metaphysics 1783 that the category of cause and effect can be applied to things-in-themselves.
"And we indeed, rightly considering objects of sense as mere appearances, confess thereby that they are based upon a thing in itself, though we know not this thing as it is in itself, but only know its appearances, viz., the way in which our senses are affected by this unknown something."

Kant can be argued to be avoiding an ontological distinction between Appearance and Things-in-Themselves in favour of a distinction between the form of an Appearance, in other words its phenomenology, and the content of an Appearance, in other words things-in-themselves. The consequence is that it is not the case that Causality can only be applied to Appearance, but can in fact be applied to the content of the Appearance as it affects the form of the Appearance. Kant claims that only the form of experience is mind-dependent, not its matter, as the matter of experience depends on a source outside the mind. Kant may be read as arguing that the sensory content is affected by the matter of mind-independent objects, things-in-themselves, while the form of experience is determined by the mind alone. Kant makes the point that the sensory content is not generated by the mind, but is generated by affection with mind-independent objects, things-in-themselves, which are then structured by the categories.
Kant wrote: the Critique posits this ground of the matter of sensory representations not once again in things, as objects of the senses, but in something super-sensible, which grounds the latter, and of which we can have no cognition. (Discovery, Ak. 8:205)

As Kant was not a phenomenologist, and believed in both Appearance and Things-in-Themselves, where the Things-in-Themselves are the cause of the Appearance, the Category of Causality cannot apply just to the Appearance but must also apply to the cause of that Appearance, ie the Things-in-Themselves.

Wikipedia - Thing-in-Itself
Claude Pichet - Kant and the problem of affection
https://hume.ucdavis.edu/kant/CAUSE.HTM
YouTube - Kant's Categories - Daniel Bonevac

It is a matter of debate whether the Kant's Category of Causality applies only to Appearances or also to Things-in-Themselves. — RussellA

He stated without equivocation the principle of causality could not, why it should now be category of causality, and that it might, I have no idea. So…..you can say whatever you like.

Kant can be argued to be avoiding an ontological distinction between Appearance and Things-in-Themselves in favour of a distinction between the form of an Appearance, in other words its phenomenology, and the content of an Appearance, in other words things-in-themselves — RussellA

Would I be right in saying that you see Kant as regarding the ding an sich as the real object, from which apparent objects are merely derivative? Does he say in so many words that the ding an sich is the cause of the appearance? Kant's philosophy implies that while there is something that exists independently of our perception (the thing-in-itself), our understanding of it is always mediated by our cognitive faculties. Therefore, while it's reasonable to think that the thing-in-itself is related to appearances, asserting a direct causal relationship in the empirical sense between the thing in itself and the appearance would be an over-extension of his philosophy - an inference of your own devising. And I think you hold to that interpretation, because you yourself are committed to a realist ontology.

So then which world is real, Appearance or Thing-in-itself? Or are they the same world? — Corvus

However, Appearance has hint of being the mental representation. Appearance is not the world either, is it? — Corvus

Suppose someone sees a red postbox.

If they were a Phenomenalist, the Appearance is the real world.

If they were an Indirect Realist, they would say that although the postbox appears red, the postbox as a Thing-in-Itself is not necessarily red. For the Indirect Realist, although the Appearance is real, the real world is the unknown Thing-in-Itself that is the cause of the Appearance.

If they were a Direct Realist, they would say that because the postbox appears red then the postbox as a Thing-in-Itself is red. For the Direct Realist, as the Appearance is directly of the thing-in-itself, not only is the real world the thing-in-itself, but they have direct knowledge of the real world through its Appearance.

As far as I know, Kant's position can be described as that of an Indirect Realist.

I see Mary in the office, being professional, managing the office, arriving on time, smartly dressed and courteous to her workmates. I see Mary on the weekend, drinking in the bar, late leaving the house, dressed sloppily, shouting at the noisy neighbour and forgetting to buy soap at the supermarket. Which is the "real" Mary?

Wittgenstein wrote in PI 404 "Though someone else sees who is in pain from the groaning" . There is the public and objective behaviour of pain, the groaning, the Appearance, describable in words and there is the private and subjective feeling of pain, the Thing-in-Itself, indescribable in words. Which is the "real" pain, the Appearance of pain or pain as a Thing-in-itself?

An Astronomer looking into the distant sky sees galaxy HD1. The Astronomer is only seeing the Appearance of HD1, a few photons of light entering their telescope that left the galaxy 13.5 billion years ago, yet HD1 as a Thing-in-Itself has the mass of possibly 1.5 trillion solar masses. Which is the "real" HD1, the Appearance of HD1 in the Astronomer's telescope or HD1 as a Thing-in-itself?

In the 1960's and 70's was developed the "dual aspect" view of the relationship between Appearance and Thing-in-Itself. In numerous passages Kant describes the appearance and thing-in-itself distinction, not as a distinction between two different objects, but as two ways of considering the same object.

Kant wrote in the Preface that even though we cannot cognize about a Thing-in-itself , we can still think about possible Things-in-Themselves as long as we are able to justify our reasoning:
Bxxvi "even if we cannot cognize these same objects as things in themselves, we at least must be able to think them as things in themselves.

Some believe in an Epistemological dual aspect, in that we can consider objects as objects of appearance or we can consider objects as things in-themselves. Others believe in a Metaphysical dual aspect, in that objects of appearance are bearers of empirical relational properties, while objects as things-in-themselves are bearers of non-empirical intrinsic properties.

The Merriam Webster Dictionary list several meanings of the word "real" as an adjective, so which meaning of the word" real" is the real one?

(SEP - Kant's Transcendental Idealism)

Would I be right in saying that you see Kant as regarding the ding an sich as the real object, from which apparent objects are merely derivative? — Wayfarer

Was Kant a Realist?

Kant was not an Idealist but a Realist, in that Things-in-Themselves in the world are the grounds for the Appearances in our minds.

Although we cannot cognize about the Thing-in-Itself, we can still think about them.
CPR Preface Bxxvi "even if we cannot cognize these same objects as things in themselves, we at least must be able to think them as things in themselves.

GJ Mattey in his lecture notes wrote about Kant's acceptance of the existence of an external world.

In Remarks II and III of Part One, Kant confronted the issue directly, and dangerously. Genuine idealists hold that the only real beings are thinking beings, everything else being representations in the thinking beings. Kant, on the other hand, denies this thesis. Appearances are appearances of things in themselves, so that what we call bodies exist not merely as representations (as stressed in the Fourth Paralogism), but as things in themselves. "I grant by all means that there are bodies without us, that is, things which, though quite unknown to us as to what they are in themselves, we yet know by the representations which their influence on our sensibility procures us. These representations we call 'bodies,' a term signifying merely the appearance of the thing which is unknown to us, but not therefore less actual. Can this be termed idealism? It is the very contrary" (Ak. 290). A vital feature of this claim is that the unknown thing is said to "influence" our sensibility, and as such, we can only postulate it as a cause. But then it seems that we are back to the original problem, i.e., the dubiousness of causal inference. Kant might respond that what is dubious in causal inference is not that there is a cause, but what the cause is. And he has admitted that the cause of our representations of bodies is unknown. "Neither the transcendental object which underlies outer appearances nor that which underlies inner intuition, is in itself either matter or a thinking being, but a ground (to us unknown) of the appearances which supply to us the empirical concept of the former as well as of the latter mode of existence" (A379-80). Unfortunately, Kant had also claimed that the concept of causality can be justifiably applied only to objects of experience, as the condition of rule-governed change of the states of empirical objects. Thus his appeal to the unknown cause of our representations falls victim to his limitation of the use of our understanding to experience.
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Does he say in so many words that the ding an sich is the cause of the appearance? — Wayfarer

Does Kant's Category of Causation apply to Things-in-Themselves?

Kant writes in Prolegomena to any Future Metaphysics 1783 that the category of cause and effect can be applied to things-in-themselves.
"And we indeed, rightly considering objects of sense as mere appearances, confess thereby that they are based upon a thing in itself, though we know not this thing as it is in itself, but only know its appearances, viz., the way in which our senses are affected by this unknown something."

It is true that the Categories in general apply only to Appearances, the Phenomena, but it can be argued that the Category of Cause is a special case and does also apply transcendentally to the Thing-in-Itself, the Noumena.

Claude Piche in his article Kant and the Problem of Affection makes this point, where he concludes:

The contribution of this paper is that I have tried to make sense of the thing in itself as the "transcendental ground" of appearances. Rather than simply consider the thing in itself as a "necessary" concept, as in Allison's view, my purpose is to demonstrate that for Kant the actuality of the thing in itself as the cause of appearances must be necessarily posited. The thing in itself is not merely an epistemic condition that we must "think"; it is a critical-metaphysical assumption that must be made, one that becomes part of philosophical knowledge. The critical philosopher knows that there is something beyond the appearances. But in this case, there is nothing dogmatic about such an assumption since it is required by the transcendental explanation of our knowledge itself. I have tried to argue that there is a legitimate philosophical use of the category of causality which links affection to the thing in itself, as long as the constraints implied by such a concept (Le., heterogeneity and indeterminateness of the correlate) are respected, even at this higher level of argumentation. The normative constraints of such a transcendental discourse cannot be empirical, nor can they be the product of pure invention. The self-referentiality of philosophy, as it has been sketched here, entails that the transcendental use of a category is permissible strictly in view of the explanation of the only way in which experience is rendered possible.
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Kant's philosophy implies that while there is something that exists independently of our perception (the thing-in-itself), our understanding of it is always mediated by our cognitive faculties. — Wayfarer

How can we talk about Things-in-Themselves if we are unable to cognize about Things-in-Themselves?

Kant wrote in the Preface that even though we cannot cognize about a Thing-in-itself , we can still think about possible Things-in-Themselves as long as we are able to justify our reasoning:
Bxxvi "even if we cannot cognize these same objects as things in themselves, we at least must be able to think them as things in themselves.

We can't talk about something that we don't even know exists, meaning that when we do talk about something either we believe it exists, believe it could possibly exist or know it exists.

As we do talk about things-in-themselves, this means that we either believe they exist, believe they could possibly exist or know they exist.

How can we believe that something exists, believe that it could possibly exist or know it exists without first cognizing about the subject of our belief or knowing?

Suppose someone sees a red postbox. — RussellA

If they were a Phenomenalist, the Appearance is the real world. — RussellA

If they were an Indirect Realist, they would say that although the postbox appears red, the postbox as a Thing-in-Itself is not necessarily red. For the Indirect Realist, although the Appearance is real, the real world is the unknown Thing-in-Itself that is the cause of the Appearance. — RussellA

1. Do the Phenomenalists claim to know the real world perceived as the appearance? Or is it unknown existence?
2. What would be the differences between Appearance of the postbox, and Sense-Data of the postbox?

Kant was not an Idealist but a Realist, in that Things-in-Themselves in the world are the grounds for the Appearances in our minds. — RussellA

I challenge that claim. I see Kant as a qualified realist - he describes himself as being at the same time, an empirical realist but also a transcendental idealist, and says that these are not in conflict. I know that there are deflationary readings of Kant, which attempt to show that he was, at heart, a realist, but then, there are many different interpretations on this point. The key factor in all this is the Kant denies that space and time have mind-independent existence.

The transcendental idealist, on the contrary, can be an empirical realist, hence, as he is called, a dualist, i.e., he can concede the existence of matter without going beyond mere self-consciousness and assuming something more than the certainty of representations in me, hence the cogito ergo sum. For because he allows this matter and even its inner possibility to be valid only for appearance– which, separated from our sensibility, is nothing –matter for him is only a species of representations (intuition), which are call external, not as if they related to objects that are external in themselves but because they relate perceptions to space, where all things are external to one another, but that space itself is in us. — A370

How can we believe that something exists, believe that it could possibly exist or know it exists without first cognizing about the subject of our belief or knowing? — RussellA

I think that you need the concept of the thing in itself to stand in for what you understand as what is real, independently of any mind, as the mind-dependence of things is too radical a position for you to accept.

It is interesting question why on seeing a broken window I instinctively believe that something broke it, even though I may never know exactly what. Why do I have a primitive belief that if something happens there must have been a reason? Why does my belief in cause and effect seem innate? — RussellA

I think your belief in the mind-independent nature of existence is innate. The following is a lengthy quote, but it brings the issue into sharp focus. It's from Bryan Magee's book on Schopenhauer's Philosophy, Schopenhauer having refined and sharpened Kant's idealism.

Schopenhauer's reformulation of Kant's theory of perception brings out implications of it which Kant touched on without giving them anything like the consideration their importance demanded ‚ and this must mean, I think, that he was not consistently aware of their importance. The first of these is that if all the characteristics we are able to ascribe to phenomena are subject-dependent then there can be no object in any sense that we are capable of attaching to the word without the existence of a subject. Anyone who supposes that if all the perceiving subjects were removed from the world then the objects, as we have any conception of them, could continue in existence all by themselves has radically failed to understand what objects are. Kant did see this, but only intermittently ‚ in the gaps, as it were, between assuming the existence of the noumenon 'out there' as the invisible sustainer of the object.

He expressed it once in a passage which, because so blindingly clear and yet so isolated, sticks out disconcertingly from his work: 'If I take away the thinking subject, the whole material world must vanish, as this world is nothing but the phenomenal appearance in the sensibility of our own subject, and is a species of this subject's representations.'

We have already mentioned one of the obvious objections to which this view appears to be open, namely the problem about the sharedness of the world. We shall return to that later. Another objection would run: 'Everyone knows that the earth, and a fortiori the universe, existed for a long time before there were any living beings, and therefore any perceiving subjects. But according to what Kant has just been quoted as saying, that is impossible.'

Schopenhauer's defence of Kant on this score was twofold. First, the objector has not understood to the very bottom the Kantian demonstration that time is one of the forms of our sensibility. The earth, say, as it was before there was life, is a field of empirical enquiry in which we have come to know a great deal; its reality is no more being denied than is the reality of perceived objects in the same room. The point is, the whole of the empirical world in space and time is the creation of our understanding, which apprehends all the objects of empirical knowledge within it as being in some part of that space and at some part of that time: and this is as true of the earth before there was life as it is of the pen I am now holding a few inches in front of my face and seeing slightly out of focus as it moves across the paper.

This, incidentally, illustrates a difficulty in the way of understanding which transcendental idealism has permanently to contend with: the assumptions of 'the inborn realism which arises from the original disposition of the intellect' enter unawares into the way in which the statements of transcendental idealism are understood, so that these statements appear faulty in ways in which, properly understood, they are not. Such realistic assumptions so pervade our normal use of concepts that the claims of transcendental idealism disclose their own non-absurdity only after difficult consideration, whereas criticisms of them at first appear cogent which on examination are seen to rest on confusion. We have to raise almost impossibly deep levels of presupposition in our own thinking and imagination to the level of self-consciousness before we are able to achieve a critical awareness of all our realistic assumptions, and thus achieve an understanding of transcendental idealism which is untainted by them.

This, of course, is one of the explanations for the almost unfathomably deep counterintuitiveness of transcendental idealism, and also for the general notion of 'depth' with which people associate Kantian and post-Kantian philosophy. Something akin to it is the reason for much of the prolonged, self-disciplined meditation involved in a number of Eastern religious practices.

Schopenhauer's second refutation of the objection under consideration is as follows. Since all imaginable characteristics of objects depend on the modes in which they are apprehended by perceiving subjects, then without at least tacitly assumed presuppositions relating to the latter no sense can be given to terms purporting to denote the former‚ in short, it is impossible to talk about material objects at all, and therefore even so much as to assert their existence, without the use of words the conditions of whose intelligibility derive from the experience of perceiving subjects. — Bryan Magee, Schopenhauer's Philosophy

Note this phrase: 'the assumptions of "the inborn realism which arises from the original disposition of the intellect" enter unawares into the way in which the statements of transcendental idealism are understood.' That is what I think I'm seeing in your analyses.

Do the Phenomenalists claim to know the real world perceived as the appearance? Or is it unknown existence? — Corvus

It's a complicated topic that I only vaguely comprehend, and can only understand using simple analogies. For example, if I put my hand on a radiator and feel intense heat, my moving my hand has been determined by my immediate experience, not by any consideration about the cause of my experience. At a later time, I can contemplate about possible reasons why the radiator was hot, but thoughts about the cause didn't determine my action, my experience determined my action .

Husserl seems central to Phenomenology. From SEP Phenomenology:
Still, the discipline of phenomenology, its roots tracing back through the centuries, came to full flower in Husserl.

Husserl's concept of "bracketing" seems important to Husserl. From Wikipedia Bracketing (phenomenology)
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.

As Husserl built on Kant's Transcendental Idealism, I imagine the Phenomenologist immediately experiences Appearance and only transcendently knows the world outside of experience. From Wikipedia Bracketing (phenomenology)
Edmund Husserl, building on Kant’s ideas, first proposed bracketing in 1913, to help better understand another’s phenomena.
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What would be the differences between Appearance of the postbox, and Sense-Data of the postbox? — Corvus

Speaking as an Indirect Realist, I would say that Appearance and Sense-data are synonyms, where both are figures of speech, and are two different ways of looking at the same thing.

This would be in opposition to the Direct Realist, who would say neither exist, in that when looking at a postbox we are looking directly at the postbox and not at some intermediary thing. IE, we are directly looking at the postbox, not a representation of the postbox.

Husserl seems central to Phenomenology. From SEP Phenomenology:
Still, the discipline of phenomenology, its roots tracing back through the centuries, came to full flower in Husserl. — RussellA

There seem different schools of Phenomenology. For example, Heidegger's Phenomenology is much different from Husserl's. Merlou-Ponty has again different Phenomenology in its methodology and subjects too. Hence framing Kant as a Phenomenologist needs close investigation i.e. first defining what Phenomenology is, then under what ground Kant is Phenomenologist or not.

Speaking as an Indirect Realist, I would say that Appearance and Sense-data are synonyms, where both are figures of speech, and are two different ways of looking at the same thing. — RussellA

I think this is a fair comment. Appearance and sense-data is very similar if not the same. Kant keeps saying Appearance and objects are the same in CPR. Would it be the ground for making Kant an Indirect Realist? Kant definitely says that TI is nothing to do with idealism in the Prolegomena.

Hence framing Kant as a Phenomenologist needs close investigation — Corvus

To my understanding, Kant cannot be described as a Phenomenologist, as phenomena are only one part of his "Transcendental Idealism".

As the IEP article Phenomenology writes:

Phenomenology, then, is the study of things as they appear (phenomena).

Kant endorsed “transcendental idealism,” distinguishing between phenomena (things as they appear) and noumena (things as they are in themselves)

On Kant’s view, the I is purely formal, playing a role in structuring experience but not itself given in experience. On Husserl’s view, the I plays this structuring role, but is also given in inner experience.
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Would it be the ground for making Kant an Indirect Realist? — Corvus

:up: I would argue that Kant is in today's terms definitely an "Indirect Realist".

I would argue that Kant is in today's terms definitely an "Indirect Realist". — RussellA

Only thing about "Indirect Realism" is that, "Indirect" sounds a bit vague. Would it not be better called something like "Representational Realism"? Because appearance and sense-data represent the contents in the mind.

Would it be the ground for making Kant an Indirect Realist? — Corvus

What would be the ground of making him anything but what he made himself?

Kant definitely says that TI is nothing to do with idealism in the Prolegomena. — Corvus

So a guy knows what TI stands for, then reads herein TI has nothing to do with idealism. What’s he to think, when he understands perfectly well that the I in TI intentionally represents idealism? Then, the poor guy, reading the reference material promising that TI has nothing to do with idealism, comes across “…The principle that throughout dominates and determines my Idealism…”, aannnndddd…..he’s farging lost it. He slams the book shut, walks off, goes back to his comic books or video games, or whatever it is that doesn’t stress his intellect enough to discover that which is at least purported as “useful truths”.

Rhetorical. The answer is in the Critique, and “…. could have been very easily understood from the general bearing of the work, if the reader had only desired to do so….”.

I challenge that claim. I see Kant as a qualified realist - he describes himself as being at the same time, an empirical realist but also a transcendental idealist, and says that these are not in conflict. I know that there are deflationary readings of Kant, which attempt to show that he was, at heart, a realist, but then, there are many different interpretations on this point. The key factor in all this is the Kant denies that space and time have mind-independent existence. — Wayfarer

It come down to definition.

Some believe that the world exists in a mind, such as Berkeley, and others believe that there is also a world that exists outside the mind, such as Kant.

I agree with the SEP article on Idealism that within modern philosophy there are sometimes taken to be two fundamental conceptions of idealism:
1) something mental (the mind, spirit, reason, will) is the ultimate foundation of all reality, or even exhaustive of reality, and
2) although the existence of something independent of the mind is conceded, everything that we can know about this mind-independent “reality” is held to be so permeated by the creative, formative, or constructive activities of the mind (of some kind or other) that all claims to knowledge must be considered, in some sense, to be a form of self-knowledge.

I agree with the SEP article of Realism that there are two general aspects to realism:
There are two general aspects to realism, illustrated by looking at realism about the everyday world of macroscopic objects and their properties. First, there is a claim about existence. Tables, rocks, the moon, and so on, all exist, as do the following facts: the table’s being square, the rock’s being made of granite, and the moon’s being spherical and yellow. The second aspect of realism about the everyday world of macroscopic objects and their properties concerns independence. The fact that the moon exists and is spherical is independent of anything anyone happens to say or think about the matter.

I agree that Kant is described as both an Empirical Realist and Transcendental Idealist. However, Kant did propose that the phrase "Transcendental Idealism" could be improved.
In the Introduction to the CPR by Paul Guyer and Allen Wood:
Specifically, he differentiated his position from Berkeleian idealism by arguing that he denied the real existence of space and time and the spatiotemporal properties of objects, but not the real existence of objects themselves distinct from our representations, and for this reason he proposed renaming his transcendental idealism with the more informative name of "formal" or "critical idealism," making it clear that his idealism concerned the form but not the existence of external objects.

The key factor that Kant denied that space and time have a mind-independent existence is similar to my position as an Indirect Realist in my belief that the colour red has no existence outside of my mind. If I see a red postbox, it is not the case that the postbox is red, but rather the postbox appears red in my mind. The fact that when I taste an apple as sweet does not mean that sweetness exists in a mind-independent world. The fact that I see a spatial relation between two objects, in that I see an apple above a table, does not mean that spatial relations ontologically exist in a mind-independent world.

To see something in the world does not of necessity mean that it exists in the world, as in bent sticks.
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I think that you need the concept of the thing in itself to stand in for what you understand as what is real, independently of any mind, as the mind-dependence of things is too radical a position for you to accept. — Wayfarer

I feel I went to sleep in Dublin and have been teletransported to Königsberg.

Concepts in the mind must refer to something. They cannot be empty terms.

We say that the concept in the mind of a thing-in-itself refers to a real thing existing in a mind-independent world.

But the problem is, things-in-themselves in a mind-independent world are by definition mind-independent.

But the concept in the mind of a thing-in-itself must refer to something. What do you think the concept in the mind of a thing-in-itself refers to?

Only thing about "Indirect Realism" is that, "Indirect" sounds a bit vague. Would it not be better called something like "Representational Realism"? Because appearance and sense-data represent the contents in the mind. — Corvus

Possibly. The Wikipedia article on Direct and Indirect Realism does give alternate names:
In the philosophy of perception and philosophy of mind, direct or naïve realism, as opposed to indirect or representational realism, are differing models that describe the nature of conscious experiences.

The problem is, is it possible to describe a theory about which millions of words have been written using just two words.

I think of "Indirect Realism" as a name rather than a description, as the Taj Mahal is the name of and not a description of a building. Similarly I think of "Transcendental Idealism" as a name rather than a description.