all attempts at an empirical deduction, in regard to pure à priori conceptions, are vain — Mww

The question remains, how does Kant justify the possibility of a "transcendental deduction?

It is not at all that properties cannot be described using words. It is that some properties require first-hand direct experience of sense data from the sense organs to be fully described. The actual smell of a rose cannot be completely put into words, thus is not an element of
the body of analytic knowledge. We can still know that some {roses} are {red} even though
we lack the sense data from the sense organs showing exactly what {red} is. — PL Olcott

Consider a computer generated language that does not depend on any external information. Rather than the expression "cats are animals", consider the more general case "X is Y". If it is possible to verify the expression as true, then the expression is analytic.

To know whether "X is Y" means knowing the meaning of "X" and the meaning of "Y".

It is impossible to discover the meaning of "X" just from knowing the name "X", similarly for "Y"

Suppose "X" can be described as "a, b, c"

It is impossible to discover the meaning of "a" just from knowing the name "a", similarly for "b" and "c".

Suppose "a" can be described as "d, e, f"

It is impossible to discover the meaning of "d" just from knowing the name "d", similarly for "e" and "f".

Suppose "d" can be described as "g, h, i"

But this ends up as an infinite regression, in that there is no name whose meaning is contained within the name itself .

IE, within a computer generated language that does not depend on any external information, as the meanings of X and Y cannot be established with absolute certainty, as the language would have to be of infinite length, it becomes impossible to determine whether "X is Y". The consequence is that it becomes impossible to know whether any expression within such a language independent of the senses is analytic or not.

Analytic expressions are expressions of language that can be verified as completely true entirely on the basis of their connection to the semantic meanings that make them true. Example: "Cats are animals". — PL Olcott

We can call this the analytic(olcott) / empirical(olcott) distinction meaning that any expression of language that can be verified as true on the basis of the axioms of the verbal model of the actual world is analytical(olcott). — PL Olcott

Starting with the expression "X is Y", let the meaning of X be the same as the meaning of Y. The expression "X is Y" is then an analytic expression as it can be verified true .

As long as it is known that two words have the same meaning, analytic expressions are possible, meaning there is a distinction between the analytic and synthetic.

However, in order to know that two words have the same meaning, the meaning of each word must be known.

A computer could invent a language from scratch that was purely self-referential.

Stage one

For example, a simple language could consist of the proposition "X is Y", where X has the properties a and b and Y has the properties c and d.

So far, X and Y have been fully specified, but the properties a, b, c and d haven't. This means that it is impossible to know whether the expression "X is Y" is true or false, in which case it cannot be analytic.

Stage two

Let the property a be named A, the property b be named B, the property c be named C and the property d be named D

But as we still don't know what the names A, B, C and D refer to, we still don't know whether the expression is true or false, in which case it is still not analytic.

Fundamental problem

The fundamental problem is that at the end of the day properties cannot be described in words. How can the sensation of pain be described, the smell of a rose, the colour red, the feeling of missing an important appointment?

Therefore, even within a computer generated language, there will be some words whose meanings cannot be described using other words. The inevitable consequence will be that it is impossible to know whether expressions such as "X is Y" are true or false. IE, even a computer generated language will not be analytic.

I think we can only know what experience, and refelection on the nature of experience tells us. We can also elaborate and extrapolate from formal rule-based systems like logic, mathematics, chess, Go etc. — Janus

In chess, the rule that the Bishop can only move diagonally is arbitrary, in that the rule could equally have been that it moves vertically or horizontally. Therefore, what happens in the world, the Bishop moving diagonally, is necessary and universal once the rule has been made, even though the rule itself is neither necessary not universal.

For Hume, no knowledge about the world, discovered by a constant conjunction of events within experiences, can be either necessary nor universal, in that, even though the sun has risen in the east for 1,000 days, there is no guarantee that on the 1,001st day it doesn't rise in the west.

However, Kant wanted to show that it is possible to discover knowledge about the world that is both necessary and universal from experiences of the world using a transcendental argument. From a careful reasoning about one's experiences, it is possible to discover pure concepts of understanding, ie, the Categories, that are necessary and universal, which can then be used to make sense of these experiences.

Introduction to CPR - page 2 - Kant also sought to defend against empiricists its underlying claim of the possibility of universal and necessary knowledge - what Kant called a priori knowledge, knowledge originating independently of experience, because no knowledge derived from any particular experience, or a posteriori knowledge, could justify a claim to universal and necessary validity.

A pictorial representation of the Transcendental Argument:

For Hume, the rules of chess, even though necessary and universal, cannot be discovered from experiences of the world, but are invented by the human intellect. For Kant, using the Transcendental Argument, the rules of chess as necessary and universal can be discovered from experiences of the world.

Hard to call passages bracketed by quotation marks as plagiarized, innit? — Mww

As the topic is front page news at the moment, it may be worth a post or two.

True, the passage is in quotation marks and we know it is somewhere within an 800 page book, but to locate it requires quite a lot of reading.

From the little I know, it is a complex and subtle subject, complicated by the fact that there is weak plagiarism and strong plagiarism, although both are officially plagiarism

I am sure that I am often guilty of breaking the letter of the law, although try not the break the spirit of the law, in that I have not made it clear which translation of the CPR I am using.

The topic is also complicated by the fact that ten different sources end up giving ten different viewpoints.

However, the site Good academic practice and avoiding plagiarism advises to give the page number of the original, and gives the example:
"Never use the passive, when you can use the active." (Orwell, 1946, p.169)

In the service of survival though, right? — Wayfarer

Yes. If animals were born with minds empty of any built-in mental content, and had to learn the private subjective feeling of pain from their subsequent experiences, by the time they had learnt to avoid anything painful that threatened their survival, they would already have died out.

From the Wikipedia article on Tabula rasa
Tabula rasa is the idea of individuals being born empty of any built-in mental content, so that all knowledge comes from later perceptions or sensory experiences. This idea is the central view posited in the theory of knowledge known as empiricism. Empiricists disagree with the doctrines of innatism or rationalism, which hold that the mind is born already in possession of certain knowledge or rational capacity.

IE, if an animal species were Empiricists, they would quickly die out.

So Darwin explains Kant? — Wayfarer

Darwin explains the a priori, not Kant.

By presupposing it given some general observations, then constructing a theory that supports the presuppositions without contradicting the observations....................Even if all the predicates of transcendental philosophy are internally consistent with each other, and coherent as a whole in itself, there is nothing given from it that makes those predicates actually the case, at the expense of other relevant philosophies. — Mww

Kant and Hume

You are saying that we come up with a theory that we use as long as it corresponds with our experiences and is coherent with the other theories we have.

But this sounds more like Hume than Kant. For Hume, we look at the world, see a particular sunrise on 100 consecutive days and theorise that in general the sun rises in the east. This then becomes an axiom (a statement or proposition which is regarded as being established, accepted, or self-evidently true) that we henceforth live by. It may be that one day the sun doesn't rise in the east, in which case we come up with a different theory and a new axiom. An approach that is only loosely necessary and universal, but in practice, works.

Kant is saying something different to Hume, in that we can know certain axioms existent in the world of necessity and universally. The question is, how exactly?

Quotations

I agree with @Corvus that you should be giving attaching paragraph numbers to your quotes. As I am using a different translation to yours, sometimes it can take me 15 minutes to find the source of your quote.

I am using the Cambridge Edition translated and edited by Paul Guyer and Allen W Wood.

I know that the elite heads of universities are allowed to plagiarise, but I don't think us common people are given the same leeway.

As you say it initially comes, not sui generis, but from a careful reflection on the nature of experience (and of course also becomes culturally established), so in that sense it is dependent on experience. It is independent of experience in that once established it is clear that all possible experience must conform to the a priori categories — Janus

This sounds like Hume's position, in that we look at the world, see a particular sunrise on 100 consecutive days and theorise that in general the sun rises in the east. This then becomes an axiom (a statement or proposition which is regarded as being established, accepted, or self-evidently true) that we henceforth live by. It may be that one day the sun doesn't rise in the east, in which case we come up with a different theory and a new axiom. An approach that is only loosely necessary and universal, but in practice, works.

Though it seems to me that Kant is saying something different to Hume, in that we can know certain axioms existent in the world of necessity and universally. The question is, how exactly?

I am separating analytic truthmakers from synthetic .........Some of these expressions such as "cats are animals" are stipulated to be true (AKA axioms). Other expressions are proven to be true on the basis of deductions from these axioms..............Any expression of language that can only be proven true with sense data from the sense organs: "A cat is in my living room right now" are excluded. — PL Olcott

As the word "are" has many different meanings, is the expression "cats are animals" true under all possible meanings of "are"?

For example, possible uses of the word "are" can include i) football fans "are" animals, ii) mountains "are" beautiful, iii) recipes "are" difficult, iv) film stars "are" gods, v) apples "are" sweet, vi) EV's "are" moral.

The general problem is that as a word only has meaning in relation to other words, and as any such relation comes down to a personal judgement on behalf of the reader, whether an expression is analytic or not depends on personal judgements rather than absolute truths.

It seems to be no mystery to me...........Hume was correct that we don't see the actual operations of causation, we don't see the forces at work, but when our bodies are involved, we can certainly feel them........................but all it does take is reflection upon our felt experience to naturally form a notion of causation. — Janus

The mystery is with Kant not Hume

There is no mystery to me with Hume's inductive approach to making sense of experiences, inferring from several particular instances a generalized conclusion. For example, in that if for one hundred consecutive days the sun rose in the east, one can comfortably infer that "the sun rises in the east".

As the IEP article on David Hume: Causation wrote:

Hume shows that experience does not tell us much. Of two events, A and B, we say that A causes B when the two always occur together, that is, are constantly conjoined. Whenever we find A, we also find B, and we have a certainty that this conjunction will continue to happen. Once we realize that “A must bring about B” is tantamount merely to “Due to their constant conjunction, we are psychologically certain that B will follow A”, then we are left with a very weak notion of necessity.

I am sure that even animals have an inductive sense of causation.

Hume is not the problem. Kant is the problem.

@Mww is correct in saying "Now you wish Kant to be fixing the dogmatism of the rationalists, but the entire reason d’etre of the Critique is aimed at the empiricists in general and Hume in particular, regarding the lack of critical examination of the capabilities and employment of pure reason herself."

Within the Critique of Pure Reason, the concept of the synthetic a priori is central.

Intro to CPR, page 6 - He entitles the question of how synthetic a priori judgments are possible the "general problem of pure reason" (B 1 9), and proposes an entirely new science in order to answer it (A IO-16/B 24-30).

How does Kant explain the origin of the a priori? How does Kant explain the origin of the Categories, the pure concepts of the understanding?

I can understand them as being innate within the human as a consequence of life's 3.5 billion years of evolving in synergy with the world. However, this is definitely not Kant's position.

For Kant, we have no innate knowledge:

Intro to CPR - page 6 - Kant agrees with Locke that we have no innate knowledge, that is, no knowledge of any particular propositions implanted in us by God or nature prior to the commencement of our individual experience.

One empirical possibility is we discoverer the Categories from our experiences of the world. Another rational possibility is that we invented the Categories from pure thought independent of any particular experiences of the world. But, Kant categorically denies that they are innate, as if they were implanted in us prior to birth by a Creator.

CPR 168 - If someone still wanted to propose a middle way between the only two, already named ways, namely, that the categories were neither self-thought a priori first principles of our cognition nor drawn from experience, but were rather subjective predispositions for thinking, implanted in us along with our existence by our author in such a way that their use would agree exactly with the laws of nature along which experience runs (a kind of prefonnation-system of pure reason), then (besides the fact that on such a hypothesis no end can be seen to how far one might drive the presupposition of predetermined predispositions for future judgments) this would be decisive against the supposed middle way: that in such a case the categories would lack the necessity that is essential to their concept.

A priori knowledge is knowledge before experience, but this does not entail innate knowledge. All innate knowledge is a priori, but not all a priori knowledge is innate. For example, all knowledge of mathematical propositions is a priori, yet this knowledge is not innate. Kant also did not equate a priori knowledge with innate knowledge.

Whereas Hume's notion of knowledge by induction gives a very weak notion of necessity, Kant's aim in the CPR was to argue for the possibility of a type of knowledge that was both universal and necessary, what Kant called a priori knowledge.

Intro to CPR - page 2 - Yet while he attempted to criticize and limit the scope of traditional metaphysics, Kant also sought to defend against empiricists its underlying claim of the possibility of universal and necessary knowledge - what Kant called a priori knowledge, knowledge originating independently of experience, because no knowledge derived from any particular experience, or a posteriori knowledge, could justify a claim to universal and necessary validity.

Where for Kant is the origin of the a priori

Kant does not believe there are any innate principles or ideas to be found in us, but come from a careful reflection on the nature of our experiences.

From the SEP article on The Historical Controversies Surrounding Innateness

In this respect Kant agrees with Locke that there are no innate principles or ideas to be ‘found’ in us. Both hold that all our ideas have their origin in experience. But Locke thinks that we build these ideas by abstracting from experience and recombining abstracted elements. Kant holds that such representations or ideas cannot be abstracted from experience; they must be the product of careful reflection on the nature of experience.

In understanding how Kant treats knowledge as a priori but not innate, a section from the SEP article of A Priorism in Moral Epistemology may be useful, in that, for Kant, a priori knowledge can be discovered as a result of careful reasoning, both transcendental and deductive.

Kant viewed moral knowledge as fundamentally a priori in the sense that moral knowledge must be the result of careful reasoning (first transcendental, then deductive); one could discover through reason the fundamental moral principle, and then deduce from that principle more specific moral duties. Moore, on the other hand, explicitly rules out reasoning to fundamental moral principles; since these principles are self-evident, Moore denies that there are, properly speaking, any reasons for them. Thus, we find in Moore a distinctively intuitionist account of a priori knowledge, as opposed to Kant’s rationalist account. Moore’s account is intuitionistic because the reason why we believe, and ought to believe, fundamental moral principles is that they are self-evident propositions that appear true to us.

The problem with causation

Any explanation of the origin of necessary and universal a priori knowledge about a world the other side of appearances as phenomena will hit the massive obstacle as pointed out by Aenesidemus. According to Kant, the Categories, including the Category of Causality, only applies to objects of experience, not Things in Themselves as the cause of such appearances. A seemingly unsurmountable problem, reinforced by Schopenhauer, who, although agreeing with Kant that behind every phenomenon is a being-in-itself, said that Kant made the mistake of trying to derive the Thing in Itself from a given representation by laws known a priori, but because a priori cannot lead to anything independent of the phenomena or representation.

Prolegomena 32 - 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.

How does Kant justify the possibility of the a priori

The SEP article wrote:

Kant holds that such representations or ideas cannot be abstracted from experience; they must be the product of careful reflection on the nature of experience.

How does Kant justify the possibility of an a priori knowledge that is both universal and necessary, if:
i) it is not innate, as if implanted in us prior to birth by our Creator
ii) it has come from a careful reflection on the nature of experience
iii) yet does not suffer from the very weak notion of necessity and universality given by Hume's inductive inferences about the world?
iv) and the Categories, including the Category of Causation, only apply to objects of experience

That does not constitute an argument. — Wayfarer

True. It's not intended to constitute an argument, more a statement of fact.

In the same way that your statement "Thus, Kant's answer to Hume was to argue that while our knowledge is grounded against experience, the fundamental structure of knowledge relies on innate capacities of the mind" does not constitute an argument, but is more a statement of fact.

Once the groundwork has been laid, then a discussion may begin.

And what would provide the basis for such ‘careful reflection’ in the absence of an innate grasp of the issue at hand? — Wayfarer

It's a mystery to me, but that seems to be Kant's position.

According to Kant, certain concepts, like causation, are not derived from experience but are rather innate to the human mind (remember, Hume and the other empiricists denied innate capacities) — Wayfarer

This is debated. For example "Several scholars take Kant's statement at face value. They claim that Kant did not endorse concept innatism, that the categories are not innate concepts and that Kant's views on innateness are significantly different from Leibniz's."
(Alberto Vanzo - Leibniz on Innate Ideas and Kant on the Origin of the Categories)

From the SEP - The Historical Controversies Surrounding Innateness

But the Lockean Empiricist approach carried the day, and innateness was written off as a backward and discredited view. Nineteenth century Kantianism, although potentially friendlier to innateness, left it on the sidelines as philosophically irrelevant.

He is certainly not an Empiricist; he sees his philosophy as a response to the challenge of Humean Empiricism. Nevertheless, he is critical of Rationalist versions of the Innateness doctrine at every turn.

Kant’s main complaint against Rationalist Nativism was that it accepted that the innate had to correspond to an independent reality, but it could not explain how we could establish such a correspondence or use it to account for the full range of our knowledge. In this, it failed to meet Hume’s challenge. Kant finds the position guilty of a number of related fatal errors.

1) Warrant. How can we establish that innate principles are true of the world? In the Prolegomena he criticizes the Innateness doctrine of his contemporary Crusius because even if a benevolent non-deceiving God was the source of the innate principles, we have no way to reliably determine which candidate principles are innate and which may pass as such (for some).
2) Psychologism. At times Kant seems to suggest that the psychologism of Rationalist Nativism is itself a problem and makes it impossible to explain how we can get knowledge of objective necessary connections (as opposed to subjective necessities).
3) Modal concepts. Callanan 2013 reads Kant as offering a Hume-style argument that Rationalist Nativism cannot explain how we could come to have a concept of objective necessity, if all we had were innate psychological principles.

In this respect Kant agrees with Locke that there are no innate principles or ideas to be ‘found’ in us. Both hold that all our ideas have their origin in experience. But Locke thinks that we build these ideas by abstracting from experience and recombining abstracted elements. Kant holds that such representations or ideas cannot be abstracted from experience; they must be the product of careful reflection on the nature of experience.

I can understand the a priori as part of the innate structure of the brain, but I don't understand Kant's a priori as a product of careful reflection on the nature of experience.

He says what appears in your sensibility can be dealt by reason, but what doesn't appear in your sensibility, but what you can think of, are Thing-in-itself. — Corvus

It seems to me that in the section on Refutation of Idealism, Kant does argue that we can use reason to transcend our sensibilities.

B275 - The proof that is demanded must therefore establish that we have experience and not merely imagination of outer things, which cannot be accomplished unless one can prove that even our inner experience, undoubted by Descartes, is possible only under the presupposition of outer experience.

B276 - Theorem - The mere, but empirically determined, consciousness of my own existence proves the existence of objects in space outside me.

B276 - Proof - I am conscious of my existence as determined in time. All time-determination presupposes something persistent in perception. This persistent thing, however, cannot be something in me, since my own existence in time can first be determined only through this persistent thing. Thus the perception of this persistent thing is possible only through a thing outside me and not through the mere representation of a thing outside me. Consequently, the determination of my existence in time is possible only by means of the existence of actual things that I perceive outside myself. Now consciousness in time is necessarily combined with the consciousness of the possibility of this time-determination: Therefore it is also necessarily combined with the existence of the things outside me, as the condition of time-determination; i.e., the consciousness of my own existence is at the same time an immediate consciousness of the existence of other things outside me.

He argues that we can prove using reason the existence of objects in space outside our sensibilities.
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If you really have to brand him what he was, he would more likely had been a transcendental realist. — Corvus

Kant was not a Transcendental Realist. From the SEP article Kant’s Transcendental Idealism

One promising place to begin understanding transcendental idealism is to look at the other philosophical positions from which Kant distinguishes it. In the “Fourth Paralogism”, he distinguishes transcendental idealism from transcendental realism:

Transcendental realism, according to this passage, is the view that objects in space and time exist independently of our experience of them, while transcendental idealism denies this.

Transcendental realism is the common-sense pre-theoretic view that objects in space and time are “things in themselves”, which Kant, of course, denies.
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Now that is Berkeley's immaterial idealism, because you deny the existence in the world, but think they all exist in your mind. — Corvus

As an Indirect Realist, I believe that a mind-independent world exists, which is the Realism part of Indirect Realism.

Reason can only deal with the objects appearing in our sensibility via experience, and that is the limit of pure reason. — Corvus

This sounds like Berkeley's Subjective Idealism, which denies the existence of material substance in the world and contends that familiar objects like tables and chairs are no more than ideas perceived by the mind, and as a result cannot exist without being perceived. IE, reason is limited by what we are able to perceive. (Wikipedia - George Berkeley)

However, Kant differentiated himself from Berkeley in not denying the real existence of objects distinct from our representation of them. From the Introduction to the CPR:
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.

Within the Refutation of Idealism is the argument that pure reason is not limited by experiences within our sensibilities, and whereas Idealism assumes that our only immediate experiences are inner experiences Kant shows that we also have immediate access to outer experiences.
B277 - Idealism assumed that the only immediate experience is inner experience, and that from that outer things could only be inferred, but, as in any case in which one infers from given effects to determinate causes, only unreliably, since the cause of the representations that we perhaps falsely ascribe to outer things can also lie in us. Yet here it is proved that outer experience is really immediate, * that only by means of it is possible not, to be sure, the consciousness of our own existence, but its determination in time, i.e., inner experience

As the Wikipedia article on Critique of Pure Reason writes:
In order to answer criticisms of the Critique of Pure Reason that Transcendental Idealism denied the reality of external objects, Kant added a section to the second edition (1787) titled "The Refutation of Idealism" which turns the "game" of idealism against itself by arguing that self-consciousness presupposes external objects.

Kant uses the idea of time to prove that external objects may be perceived directly enabling pure reason to transcend experiences within our sensibilities.
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If Thing-in-itself exists in the empirical world, and thought to appear in phenomenon, then it would be contradiction. — Corvus

For the Direct Realist, the thing in itself in the world does appear in appearance as phenomena, ie, when we perceive the colour red there is a colour red existing in the world. This is why Kant is not a Direct Realist.
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It doesn't make sense to me, when you say, the postbox exist in the empirical world, but the red patch exists in your mind. — Corvus

Perhaps because that's not something I said. As an Indirect Realist, as the colour red exists in the mind and the not the world, the postbox also exists in the mind and not the world.

For the Direct Realist, as the colour red exists both in the mind and the world, the postbox also exists in both the mind and the world.

in the sense of transcendental idealism, is it not the case that the unity of perceptions of a given object actually represent a 'whole' object rather than merely a set of properties — AmadeusD

In Transcendental Idealism there is a priori pure intuition of space and time and a priori pure concepts of the understanding, ie, the Categories

Therefore, Transcendental Idealism applies to appearance in the mind not objects in the world. ie Transcendental Idealism applies to phenomena not noumena (though whether the Category of cause can apply to noumena is debated).

Yes, as the unity of perception of a given object is about an object that appears in the mind not as it actually is in the world, Kant's unity of perception is about a whole rather than a disparate set of parts.
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'Horseness' doesn't consist in any properties of the horse, but the totality of those properties, under certain concepts. Take away the 'brownness' and it's still a horse. Take away 'horse-hairy-ness' and it's still a horse. Take away the mane, the hoofs etc.. In parts, and Horseness remains. — AmadeusD

If there is something in the world which doesn't have the properties of brownness, horse-hairy-ness, mane and hoofs, would anyone looking at this something think that it was actually a horse?

Solid ground for infallible knowledge is about the objects in the empirical world. Noumena is for the A priori perceptions which have no objects in the world of appearance. Noumena has nothing to do with the solid material existence in the empirical world. — Corvus

Then where does Kant get his solid ground for infallible knowledge of solid material existence in the empirical world?
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It gets all strange, if you place the ordinary objects like cups or trees into Noumena, and say they are Thing-in-itself, which are unknowable and cannot be talked about. — Corvus

For the Indirect Realist, the colour red exists in the mind but not the world, though there is something in the world that caused our perception of the colour red. When the Indirect Realist talks about the colour red, they are referring to two distinct things, the known colour red in the mind and the unknown something in the world that caused our perception of the colour red.

For the Direct Realist, the colour red exists both in the mind and the world, When the Direct Realist talks about the colour red, they are referring to one thing.

Do you believe that the colour red exists in the world?

1. You are talking about only the things in your mind. It will not give you any further knowledge on the external world itself. You say you are seeing the red postbox, but it is in your mind, and it doesn't exist in the world. So it is not an empirical knowledge, but it is your belief in your mind, which you admit that it doesn't exist in the world. — Corvus

As an Indirect Realist, from the Indirect part of Indirect Realism, the red postbox exists in my mind and not the world. From the Realism part of Indirect Realism, something exists in the world which may or may not be the same as what exists in my mind.
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2. There is also high possibility of illusion and hallucination on the perception and also talking about them, which are not the reality in the empirical world. — Corvus

Yes, The Argument from Illusion against Direct Realism

The Argument from Illusion, found in Berkeley, Hume, Russell, and Ayer, begins from the familiar fact that things sometimes look other than they are (perceptual relativity, illusions, hallucinations) and concludes that we only directly (or immediately) perceive our own ideas (or sense data).

(Lecture II The Argument from Illusion - Penelope Maddy)
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3. These are not what Kant thinks how perception works. He was seeking to establish a solid ground for infallible knowledge. He would be seriously worried to see someone looking at things not existing in the world, and keeps talking about them as if they do exist in the world, and at the same time saying they don't exist in the world — Corvus

Where does Kant get his solid ground for infallible knowledge of noumena?

It sounds gross self-contradictory to say "matter existing in the world is noumena", and then keeps going on "noumena cannot be cognized, it cannot therefore be talked about"......................How can "matter" be talked about as "unknown causes"? Do you mean they are the same? How so? — Corvus

"Matter" and "red" are words in language and concepts in the mind. As I perceive a red postbox in the world, I can also perceive solid matter in the world.

I can talk about red postboxes in the world even though what is referred to as the colour red doesn't exist in the world. Similarly, I can talk about solid matter in the world even though what is referred to as matter doesn't exist in the world.

From an innate belief in the Law of Causation, the Principle of Sufficient Reason, an appearance has a prior cause. If a known appearance in the mind is named "red", the unknown cause in the world can be named "X". "X" does not refer to a known thing in the world but refers to an unknown prior cause of a known effect. This prior cause can have happened at any time and can have been of any kind. For convenience within language, "X" is re-named "red".

So how were you able to talk about "the matter of the Eiffel Tower", if you couldn't know it? Is it possible to know what "the matter" means? — Corvus

For Kant, matter existing in the world is noumena, and as noumena cannot be cognized, it cannot therefore be talked about

From the SEP article on Kant’s Critique of Metaphysics
Throughout the Analytic Kant elaborates on this general view, noting that the transcendental employment of the understanding, which aims towards knowledge of things independently of experience (and thus knowledge of “noumena”), is illicit (cf. A246/B303).

From the SEP article Kant’s Transcendental Idealism:
In the section “On the ground of the distinction of all objects into phenomena and noumena”, which he substantially revised for the B Edition, Kant reiterates his argument that we cannot cognize objects beyond the bounds of possible experience, and introduces a complex distinction between phenomena and noumena....................Clearly, we do not cognize any noumena, since to cognize an object for us requires intuition and our intuition is sensible, not intellectual.

As Kant wrote:
A249 - if, however, I suppose that there be things that are merely objects of the understanding and that, nevertheless, can be given to an intuition, although not to sensible intuition (as coram intuiti intellectuali), then such things would be called noumena (intelligibilia).

I can talk about "matter" as unknown causes are named after known appearances

I can talk about seeing a red postbox in the world, even though the colour red doesn't exist in the world, but only in the mind. The cause of an appearance is named after the appearance, in that if the appearance is red, the cause is named red.

As the SEP article on Kant’s Critique of Metaphysics writes:
Filling this out, Kant suggests that to take ourselves to have unmediated intellectual access to objects (to have “non-sensible” knowledge) correlates with the assumption that there are non-sensible objects that we can know. To assume this, however, is to conflate “phenomena” (or appearances) with “noumena” (or things in themselves). The failure to draw the distinction between appearances and things in themselves is the hallmark of all those pernicious systems of thought that stand under the title of “transcendental realism.”

In practice, unknown noumena are named after known phenomena. IE, if our perception is named red, the unknown cause of our perception is also named red. The word red then has two distinct meanings, first as the known perception in the mind and second as the unknown cause in the world. Problems arise when these two distinct meanings are conflated. IE, when I talk about seeing a red postbox in the world, what I am talking about is not an unknown something existing in the world but a known appearance existing in the mind.

The Eiffel Tower is indeed an idea, which has been realized (made real) in iron. Without the idea, no such thing could have been wrought. The resulting artefact is an ideal exemplar of the synthesis of matter and form. — Wayfarer

For Kant, we know the form of the Eiffel Tower from its appearance as phenomena. However, we cannot know the matter of the Eiffel Tower from Sensible Intuition, as it is noumena.

A249 - Appearances, to the extent that as objects they are thought in accordance with the unity of the categories, are called phaenomena. If, however, I suppose there to be things that are merely objects of the understanding and that, nevertheless, can be given to an intuition, although not to sensible intuition (as coram intuiti intellectuali),then such things would be called noumena (intelligibilia).

Are things more than their parts? — AmadeusD

If all the metal was removed from the Eiffel Tower, what would be left. An idea of the Eiffel Tower would be left.

If by "thing" one means an idea in the mind as well as physical parts in the world, then, yes, things are more than their physical parts.

The question he has is somewhat similar to mine.................his question is Kant's use of the word 'experience' with regard to delineating between 'understanding' and 'intuition'. He is asking why Kant thought he could get away with the premise that het two are necessarily distinct and why, with regard to Humean/Leibnizian alternatives, he thought it could not be argued against. — AmadeusD

Robert Paul Wolff

Wolff said "the foundation of the distinction is that Kant thinks that through sensibility we are placed in direct relation with individual things, and through conception and understanding we are placed in indirect relation through general concepts to individual things. IE, we can look at a particular horse, but we need to bring it under the general concept of horse, the particular falls under the general. He doesn't think this can be reduced to the same thing but they are different things"

The difference between the particular and the general

There is a difference between a particular and the general. For example, we look at a field and see at one moment in time and one particular position in space a particular set of shapes and colours. We can then generalise, ie, conceptualise, a horse .

We can only come up with the general concept of a horse after seeing several particular example of a horse.

For Kant, an Intuition can be i) Sensible Intuition, ie, phenomena - ii) Non-sensible Intuition, ie, noumena - iii) Pure Intuition, ie space and time. What all these have in common that it is intuition of one particular thing, ie, a set of shapes and colours we see in the field at one moment in space and time

For Kant, our Principles of Understanding can be discovered from our Concepts of Understanding, ie the Categories, For example, such Principles of Understanding would include: i) the conservation of energy ii) qualities inhere in substances iii) things don't happen randomly. What all these have in common is that the concept is not about one particular thing, but is about a set of particular things under the umbrella of a single idea.

The question is, after seeing several particular sets of shapes and colours in a field through space and time, how do we understand that they are connected in some way under the single idea of a "horse".

The Empiricists Hume and Locke thought that we discover the concept of horse just from the experience of seeing several instantiations of a horse. Kant thought that we can only discover the concept of horse from a combination of a priori knowledge independent of experience together with empirical experience.

For Hume, we would infer the concept of horse from the constant conjunction of states of affairs in the world. For Kant, we would know the concept of horse because our experiences fulfilled an a priori understanding.

Does the colour red exist in the world or the mind

The question is how we establish general concepts from several particular example. For example, we see the colour red when looking at wavelengths between 620nm and 750nm.

Are the Empiricists correct when they propose that we have learnt the concept of red from looking at all the wavelengths from 620nm to 750nm and finding a similarity in them. Are the Innatists correct when they propose that we know the concept of red a priori, before even looking at wavelengths, and only need to look at a single wavelength, say 700nm, in order to recognize it as the colour red. (Accepting that it is disputed whether or not Kant endorsed concept innatism)

If the Empiricist are correct, the colour red exists in the world and we discover it. If the Innatists are correct the ability to perceive the colour red exists in the mind which we then recognize in the world.

Objects are sets of properties

An object such as a horse is a set of properties, such as colour, texture, smell, taste, etc. In fact, an object is only its set of properties, in that if all the object's properties were removed, then no object would remain.

If the Innatists are correct in that the ability to perceive the colour red exists in the mind prior to experiencing the world, a similar argument can be made for all the other properties. Butt as an object is no more than its set set of properties, then our understanding of what an object is, as illustrated by the CPR, is dependent not only what we experience but also on an a prior ability in being able to recognize what we experience.

(Kant's Categories - Daniel Bonevac)
(Leibniz on Innate Ideas and Kant on the Origin of the Categories)

You couldn't possibly have the concept without the phenomena — AmadeusD

Some concepts are innate prior to any phenomena

Suppose you touch sandpaper and feel a rough sensation and then touch silk and feel a smooth sensation. You have the concepts of rough and smooth and you have the phenomenal experiences of sandpaper and silk

Why is it when touching sandpaper you feel a rough sensation rather than a smooth sensation? Is it because i) within the phenomena there are already sensations that will be subsequently experienced or ii) the sensations pre-exist any experience of the phenomena ?

I would suggest that concepts such as rough and smooth are innate and pre-exist any phenomena subsequently experienced.

One assumes that if what Kant says is true in the CPR, then it must be understandable in ordinary terms, otherwise it isn't relevant.

Trying to understand Transcendental Idealism and Empirical Realism using the analogy of colour:

1) For Kant, there are the a priori pure intuitions of space and time and the a priori pure concepts of understanding, ie the Categories. Although both a priori, the pure intuitions of space and time precedes and provides the framework for the pure concepts of understanding, in that I can imagine space and time with no objects within it but I cannot imagine objects not in a space and time.
2) Space and time are intuitions because singular, and the Categories are concepts because general.
3) Of the four Categories, quantity, quality, relation and modality, colour is within the Category of quality.
4) Kant's Innatism, in the belief in a priori knowledge is a counter to Locke's Empiricism, in that the mind is a "Tabula Rasa" at birth.

5) I am born with the ability to see the colour red when looking at a wavelength of 700nm
6) I am not born with any ability to see a colour when looking at a wavelength of 300nm
7) Necessary, because when looking at a particular wavelength, I always perceive the same colour, in that I cannot decide sometimes to see the colour green and other times to see the colour blue. Universal, because in whatever space and time I happen to be in, when looking at a particular wavelength, I always perceive the same colour.

8) It is a Sensible Intuition in the sense that I perceive the colour red when looking at the single wavelength of 700nm
9) It is a Concept in the sense that I perceive the colour red when looking at wavelengths from 620nm to 750nm
10) I am not born with the Concept of the colour red or a Sensible Intuition of the colour red, in that when not looking at a wavelength between 620nm and 750nm I cannot imagine the colour red. I am born with the ability to perceive colour only when looking at a particular wavelength of light.

11) Perceiving a colour requires neither Judgement nor Understanding.

12) When we perceive colour, we are perceiving something as an Appearance, a Phenomenon. We are not perceiving the cause of that Appearance, a Noumenon.
13) However, from our inherent belief in the Principle of Sufficient Reason and the Law of Causation, we believe that something must have caused the phenomena that we perceive, and we can name these unknown things noumena
14) Even though noumena are the cause of phenomena, this does not mean that a phenomenon is the same as the Noumenon that caused it. For example, even though I perceive the colour red, the colour red doesn't exist in the world, what exists in the world is a wavelength 700nm.
15) From my belief in the Principle of Sufficient Reason, my belief in a wavelength of 700nm as the cause of my seeing the colour red is a Non-Sensible Intuition.

It must be the case that if the CPR is true, no matter how complex it is as a book, its truth must be applicable to simple examples.

I am not sure if your justification using innate-ism were coherent for your premises or conclusions. — Corvus

Kant doesn't justify his premise that we have a priori pure intuitions and a priori pure concepts of the understanding.

I suggest that his premise can be justified by the Principle of Innatism, a natural consequence of 3.5 billion years of evolution.

Is there a better justification for his premise?

whatever judgements are made about the world, the mind provides the framework within which such judgements are meaningful. So though we know that prior to the evolution of life there must have been a Universe with no intelligent beings in it, or that there are empty rooms with no inhabitants, or objects unseen by any eye- the existence of all such supposedly unseen realities still relies on an implicit perspective. What their existence might be outside of any perspective is meaningless and unintelligible, as a matter of both fact and principle — Wayfarer

Although my position is from Indirect Realism, can it be true that the content of all the scientific literature about the Universe prior to life can be dismissed as meaningless and unintelligible?

After all, Kant was neither a Berkelian Idealist nor Phenomenalist.

The origin of A priori ideas in biological psychological sense would be in the interest of the evolutionary science rather than Philosophy. — Corvus

Surely good philosophy needs to justify its premises.

If I said that aliens from Mars are running all governments, and made no attempt to justify my statement, I would get nowhere.

Similarly, if I based a philosophy on the premise of a priori pure intuitions and a priori pure concepts of the understanding without attempting to justify my premise, my philosophy has been based on a weak foundation and will thereby be unpersuasive to many.

'Objective and independent' stands in contradiction to 'within language'. — Wayfarer

Isn't it admirable within philosophical language to be objective and have an independent point of view?
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We cannot consider a mind-independent world, because to consider anything is to make it the subject of thought. You refer to 'the mind dependent' and 'mind independent' as if these are two separate realities, but that is comparison that can't be made. — Wayfarer

Yet we consider a mind-independent world every time we talk about the Universe before life began on Earth. For example, The Origins of the Universe by Michael Greshko
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I'll bow out now unless I have something to add specific to the text. — Wayfarer

The question is, is a discussion about the terms "mind dependent" and "mind independent", which Kant didn't use, relevant to a text that does refer to "phenomena" and "noumena"?

Kant was saying that pure intuitions and concepts are the the properties of our minds which work with pure reason in CPR. He is not interested in where they came from — Corvus

Possibly, but his philosophy isn't complete without asking where these a priori pure intuitions and a priori Categories came from.
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For example 2+2=4 is A priori knowledge, which is universally and necessarily true in the whole universe.----------------That sounds like extreme idealism. We are talking about the universally and necessarily true knowledge, and it exists. Again it is nothing to do with the physical universe. Knowledge exists in our understanding. Universally doesn't mean the physical universe. It means "under all conditions". — Corvus

When you refer to "universe" do you mean a universe within the mind or a universe external to the mind?
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You just committed a self-contradiction here. You shouldn't even be able to write about it, if above were true. — Corvus

From the Principle of Sufficient Reason, an appearance must have a cause, which may well be unknown. This unknown cause can be called "x", or even "Thing-in-Itself".
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But I know they exist, because I read about them. Just because I know something doesn't mean that I must believe in it too.-----------------I have demonstrated how the official definitions could be false, but you have gone back to the false official definition ignoring the real life demonstration and evidence. — Corvus

How can you know atoms exist, yet not believe in their existence?

When you say "Innatism", it denotes psychological or biological nature rather than epistemic, conceptual nature, and it has nothing to do what Kant was meaning for A priori. — Corvus

For Kant there is a priori pure intuition of space and time and the a priori pure concepts of the understanding (the Categories)

These are necessary for the possibility of experience, and are priori to experience. They don't come from the mind but are part of the mind.

My question is, where did these pure intuitions and pure concepts come from?

From a perspective of today, I can explain them using the concept of Innatism, in that we were born with them as part of the structure of the brain as a consequence of 3.5 billion years of evolution.

If not from Innatism, where do you think our pure intuitions and pure concepts came from?
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For example 2+2=4 is A priori knowledge, which is universally and necessarily true in the whole universe. — Corvus

For Kant there is a priori pure intuition of space and time and the a priori pure concepts of the understanding (the Categories).

For example, the Categories include quantity, quality, relation and modality, and quantity includes such things as all, both, most and some.

This allows us when looking at a set of objects to make judgements such as "all the objects green", "both objects are blue", "most of the objects are orange" and "some of the objects are purple".

Then, given ten objects of which six are orange, some of these statements will be true and some will be false. For example, the statement "most of the objects are orange" will be true.

As no situation can be imagined whereby given ten objects of which six are orange, the statement "most of the objects are orange" will not be true, meaning that it is universally and necessarily true.

However, the Categories don't apply to unknown Things-in-Themselves, but only to known Appearances.

As this is the case, then what does universal and necessary refer to. They cannot refer to the world of Things-in-Themselves, as these are unknowable, but can only refer to the world of Appearance, as only this is knowable, and the world of Appearance only exists in the mind of the perceiver.

Therefore, it is true that a priori knowledge is universally and necessarily true in the whole universe, but this universe only exists in the mind of the perceiver, not in any world that exists outside the mind of the perceiver.
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Justified true belief has stronger ground than a knowledge via heard through the grapevine. I really don't believe the electrons, atoms and Andromeda galaxies exist, because I have never seen them, or been there. But I know they exist, because I read about them. — Corvus

Knowledge is justified true belief, so knowledge has a stronger ground than belief.

If from the grapevine one hears the belief that atoms exist, and the grapevine justifies the claim, and in fact atoms do exist, then, and only then, is this knowledge.

But that is an oxymoron — Wayfarer

If the concept of "apple" didn't exist, how could we be talking about the concept of "apple"?
If the word "apple" wasn't real, how could we be writing about the word "apple"?
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Werner Heisenberg, who aside from being one of the architects of quantum theory, also wrote on its philosophical implications, said that electrons 'do not exist in the same way that flowers or stones do' — Wayfarer

Consider the mind and a mind-independent world.

As regards a mind-independent world, as flowers and stones are sets of elementary particles, flowers and stones must exist in the same way that elementary particles exist.

As regards the mind, as flowers, stones and elementary particles are concepts in the mind, elementary particles exist in the same way that flowers and stones do .

It is true that elementary particles, flowers and stones exist differently in the mind to how they exist in a mind-independent world.

As regards a mind-independent world, Plato's Forms are aspatial and atemporal, which is not the case for elementary particles.
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I too am an empirical realist - there really are apples - but I also recognise the sense in which they exist for a subject. Another kind of being might not see them at all, or might see them in a completely different way. It doesn't mean that they don't exist, but that they don't have inherent existence — Wayfarer

Yes, for the Empirical Realist, the apple that is perceived is a mere representation, not something that is mind-independent.

When you say the apple exists, but doesn't have inherent existence, what do you mean?

I don't think your depiction of a priori as subjective is correct — Wayfarer

I agree that my innate ability to see the colour red when looking at a wavelength of 700nm is not a subjective ability, although my seeing the colour red is a subjective experience .
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The problem with that view is that the manner in which electrons can be said to exist is not at all straightforward.........................We have to get our head around the role of the mind-brain in constructing/creating what we perceive as reality. — Wayfarer

Do electrons really exist?

It depends what you mean by "exist". The Merriam Webster Dictionary includes "exist" as "to have real being whether material or spiritual".

It depends what you mean by "real". The Merriam Webster Dictionary includes "real" as "having objective independent existence".

From my belief in Neutral Monism, I could ask the same question about apples: "Do apples really exist?"

My answer would be that yes, "apples" and "electrons" do exist, and they exist as concepts in the mind.

My answer would also be that "apples" and "electrons" are real in that they have an objective independent existence within language.

If A priori is just innate to you, and all different from person to person, then what is the point of A priori? Would it not better just as well call it as Relative concept rather than A priori? There must be some universality and necessity in truth on A priori, and that was what Kant was after in CPR.........................I can't know what your perception of WL700nm would be like, and that was the point. — Corvus

The point of the a priori is that it distinguishes two very different approaches to the relationship between the mind and the world.

It distinguishes between Innatism, the philosophical belief that one is born with certain ideas and knowledge, and Locke's idea that the mind at birth is a blank sheet, a tabula rasa, devoid of all ideas or knowledge, where all our ideas and knowledge arrive from experience.

For Kant, the mind has a role in constructing what we perceive as reality:
A239 - We can only cognize objects that we can, in principle, intuit. Consequently, we can only cognize objects in space and time, appearances. We cannot cognize things in themselves.

I agree that there is the question as to the universality and necessity of such a priori ideas and knowledge :
Introduction - Kant also sought to defend against empiricists its underlying claim of the possibility of universal and necessary knowledge - what Kant called a priori knowledge, knowledge originating independently of experience, because no knowledge derived from any particular experience, or a posteriori knowledge, could justify a claim to universal and necessary validity.

As Hume showed, no a posteriori knowledge can justify a universal and necessary validity, in that a scientist can draw a conclusion from 1,000 measurements, yet that conclusion may be negated by the 1,001st measurement.

It is true that for me, my a priori ideas and knowledge, because they are a priori, ensure a universality and necessity to what I cognize. However, humans do not exist as a hive mind but as separate individuals.

My a priori ideas and knowledge ensure a universality and necessity to what I cognize, and your a priori ideas and knowledge ensure a universality and necessity to what you cognize. The question is, is there any reason to believe that your a priori ideas and knowledge are the same as my a priori ideas and knowledge. If not, even though there is a universality and necessity to our individual ideas and knowledge, our separate ideas and knowledge don't necessarily share a common universality and necessity.
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I know the Andromeda Galaxy exists, but I don't believe it exists. — Corvus

I think that this should be the other way round: "I believe the Andromeda Galaxy exists, but I don't know it exists"

The SEP article on The Analysis of Knowledge discusses knowledge as justified true belief. First one has a belief, and then one tries to justify this belief, and if one's belief is true, then one has knowledge

IE, belief comes before knowledge.
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Yes, but my question was how do you know it is real or illusion? — Corvus

The Merriam Webster Dictionary includes the meaning of "illusion" as
1a1 - a misleading image presented to the vision
1a2 - something that deceives or misleads intellectually
1b1 - perception of something objectively existing in such a way as to cause misinterpretation of its actual nature

If I perceive a tree, how do I know there is a real tree in the world or the tree only exists in my mind.

The Direct Realist would say that they perceive a tree, and the Indirect Realist would say that they perceive a representation of a tree.

For the Indirect Realist, if "illusion" means 1a2 or 1b1, then the tree is an illusion as the viewer is being misled in thinking that what they perceive of necessity actually exists in the world. If "illusion" means 1a1, then the tree is not an illusion, as the viewer is not being misled in thinking that their perception doesn't exist.

A priori means that it is universally true under all circumstances. — Corvus

The IEP article on A Priori and A Posteriori writes: An a priori concept is one that can be acquired independently of experience, which may – but need not – involve its being innate, while the acquisition of an a posteriori concept requires experience.

A Priori does not mean universally true for all people at all times. A priori means in a sense innate within a particular person. My private subjective experience of colour when seeing a wavelength of 700nm is innate to me.

How can you know that when you are look at a wavelength of 700nm, your private subjective experience of colour is the same as mine?
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How / Why do you justify your belief in something that you cannot prove it exists? — Corvus

I cannot prove that electrons exist, yet I believe they exist. I justify my belief from the numerous scientific articles that I have read that say that electrons do exist.

Do you believe that the Andromeda Galaxy exists? Can you prove that it exists?
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what is the relation between the colour you perceive (red), and the WL700nm? — Corvus

Totally mysterious. What do you think the relationship is?
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How does he know for certain what he is conscious of is not an illusion? — Corvus

Isn't this the argument against Direct Realism, in that if Direct Realism was true, the external world would be exactly as we perceive it. However, in the case of illusions, there is an obvious difference between our perception and reality. For example, when a pencil is placed in a glass of water, it can look crooked. But it isn't really crooked.

Kant was definitely not a Direct Realist.

How does the Direct Realist know when looking at something in the world, such as a tree, that what they think they are looking at is just an illusion?
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Does this mean, if something was conscious of itself, then it could be inside him? — Corvus

Not everyone agrees with Kant's Transcendental Argument.

If I am conscious of the passing of time, then I must be conscious of two different moments in time. But how is this possible if I only exist at one moment in time?

Any popular media based information will be flatly rejected as propaganda in all philosophical discussions unless proved and verified otherwise — Corvus

Yes, every source is open to doubt, even the SEP, which is the premier reference work in philosophy.

We know it is the premier work in philosophy because the Stanford Department of Philosophy says so. They write: The Stanford Encyclopedia of Philosophy (SEP) is the premier reference work in philosophy, and covers an enormous range of philosophical topics through in-depth entries.
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When you say, we impose space and temporal forms on the sensory experiences, it does imply we can also choose not to impose as well. — Corvus

No, because this imposition is a priori, and as priori is beyond choice. In the same way that when I see the wavelength of 700nm I have no choice as to what colour I perceive .
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Wasn't Kant refuting the rationalists rather than idealism? If it were idealists, who were they? — Corvus

As the Wikipedia article on Transcendental arguments concludes: He has not established that outer objects exist, but only that the concept of them is legitimate, contrary to idealism

From the Britannica article on Rationalism: Rationalism, in Western philosophy, the view that regards reason as the chief source and test of knowledge.

From Routledge Encyclopedia of Philosophy:Idealism is now usually understood in philosophy as the view that mind is the most basic reality and that the physical world exists only as an appearance to or expression of mind, or as somehow mental in its inner essence.

In B275, Kant mentions Berkeley as an example of a Dogmatic Idealist, someone who declares the existence of objects outside us to be either false or impossible

Kant is refuting Idealism as a belief rather than Rationalism as a method .
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What is the proof of the legitimacy of the concept that things exist independently of the mind? — Corvus

Speaking as an Indirect Realist, none. I believe that things exist independently of the mind, and can come up with reasons to justify my belief, but cannot prove it. Such is the nature of Indirect Realism.

This is a question for the Direct Realist, who does believe that they directly perceive things that exist independently of the mind.
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Any relevant quotes for this argument from CPR? — Corvus

In B275 is the section on The Refutation of Idealism

He includes the Theorem: The mere, but empirically determined, consciousness of my own existence proves the existence of objects in space outside me.

In B276 is the section Proof

I am conscious of my existence as determined in time. All time-determination presupposes something persistent in perception. This persistent thing, however, cannot be something in me, since my own existence in time can first be determined only through this persistent thing. Thus the perception of this persistent thing is possible only through a thing outside me and not through the mere representation of a thing outside me. Consequently, the determination of my existence in time is possible only by means of the existence of actual things that I perceive outside myself. Now consciousness in time is necessarily combined with the consciousness of the possibility of this time-determination: Therefore it is also necessarily combined with the existence of the things outside me, as the condition of time-determination; i.e., the consciousness of my own existence is at the same time an immediate consciousness of the existence of other things outside me.

In other words:

1) I am conscious of my existence in time
2) Therefore I am conscious of something persisting in time
3) But this something that persists in time cannot be inside me, as this something cannot be conscious of itself
4) Therefore as this something that persists cannot be a representation inside me, this something that persists must be outside me.
5) Concluding that there must be something outside me, refuting Idealism which believes there is nothing outside me.

I don't subscribe to the most of Wiki info. — Corvus

As with most sources, whether Fox or CNN, whether the BBC or Talk TV, one has to make a personal judgement as to whether the source makes a logical and reasoned case.
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From the traditional logic perspective, they insist that contents is not dealt by logic. Fair enough on that. But from all the other logic, content itself is important part of logic. If you read Bolzano's Theory of Science, you would agree. — Corvus

What is a Transcendental argument

From the Wikipedia article on Transcendental arguments, which presumably uses transcendental logic, Kant used transcendental arguments to show that sensory experiences would not be possible if we did not impose their spatial and temporal forms on them

In the Critique of Pure Reason (1781) Kant developed one of philosophy's most famous transcendental arguments in 'The Deduction of the Pure Concepts of the Understanding'.[8] In the 'Transcendental Aesthetic', Kant used transcendental arguments to show that sensory experiences would not be possible if we did not impose their spatial and temporal forms on them, making space and time "conditions of the possibility of experience".

An example of a Transcendental argument is used by Kant in his refutation of idealism. Idealists believe that things have no existence independently of the mind. His Transcendental argument does not prove that things exist independently of the mind, only that the concept that things exist independently of the mind is legitimate.

Kant argues that:
1) since idealists acknowledge that we have an inner mental life, and
2) an inner life of self-awareness is bound up with the concepts of objects which are not inner, and which interact causally,
3) then we must have legitimate experience of outer objects which interact causally.

I can make a similar Transcendental argument:
1) A postbox emits a light having a wavelength of 700nm, and because I have the innate ability to perceive the colour red when looking at a wavelength of 700nm, I perceive the colour red.
2) I perceive the postbox as red not because the postbox is red but because I perceive the postbox as red.

My argument doesn't prove that the postbox is not red, but only the possibility that the postbox is not of necessity red.

Is "bachelors are unmarried" an analytical statement

As regards the statement "bachelors are unmarried men", when thinking about what the words refer to, as both "bachelor" and "unmarried men" refer to the same thing, the statement is analytic. However, when thinking about the sense of the words, as the sense of "bachelor" is different to the sense of "unmarried men", they don't refer to the same thing, and so is not an analytic statement.

IE, the content or sense of the words must be taken into account , not just their form or reference.

They sounded to have read somewhere about the traditional logic, and it is the only form of logic in existence, and have been opposing on the view that Logic can require contents for its operation. :roll: — Corvus

The SEP article on Kant’s Transcendental Arguments, section 3, shows that Kant is still relevant today.

Kant-inspired transcendental arguments against scepticism about the external world were developed with vigor in the mid-twentieth century, notably by P. F. Strawson, most famously in his Kantian reflections in The Bounds of Sense (1966). These arguments are often reinterpretations of, or at least inspired by, Kant’s Transcendental Deduction and his Refutation of Idealism.

The article writes that Strawson’s most famous transcendental argument in 1966 is modelled on the Transcendental Deduction, where Strawson's target is sense-datum experience.

However, according to the Wikipedia article on Logic, logic only deals with the form of an argument and not the content of an argument:
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or logical truths. It studies how conclusions follow from premises due to the structure of arguments alone, independent of their topic and content.

However, the Wikipedia article assumes the possibility of the separation of form from content. But that cannot be the case, in that if all the content was removed, what form would be left. If all the metal was removed from the Eiffel Tower, what would remain?

What pitfalls must i avoid in reading this section? — AmadeusD

I would say that the biggest pitfall is reading it in isolation of secondary sources, which might include:

IEP - Immanuel Kant: Logic
He insists that formal logic should abstract from all content of knowledge and deal only with our faculty of understanding (intellect, Verstand) and our forms of thought.

SEP - Kant’s Transcendental Arguments
Among Immanuel Kant’s (1724–1804) most influential contributions to philosophy is his development of the transcendental argument. In Kant’s conception, an argument of this kind begins with a compelling premise about our thought, experience, or knowledge, and then reasons to a conclusion that is a substantive and unobvious presupposition and necessary condition of this premise.

The Generality of Kant’s Transcendental Logic - Clinton Tolley - University of California
Unlike the traditional logic, which focuses only on the form of thinking and judging, Kant intends his new transcendental logic to focus on the content of thinking and judging, albeit in a very abstract manner.

Generation Online - Transcendental Logic
Kant defines transcendental logic, on the other hand, as a subdivision of general logic, and distinguishes it from general logic in so far as transcendental logic does not abstract from all the contents of knowledge, but takes from transcendental aesthetics the forms of pure intuition of space and time into consideration, thus abstracting from empirical contents, whilst still accounting for pure intuitions.

These secondary sources point at a distinction between the importance of the form of a logical statement in traditional logic and the importance of the content of a logical statement in transcendental logic

Perhaps this means that a logical stalemate is as much dependent on its content as its form.

Once again….red is not a thing. Wavelength is a thing, but is not an sensation. — Mww

Of course, sensations in the mind are caused by things in the world. Au revoir.