We infer that they see things differently on the basis of observation and analysis of their different sensory setups. We can infer that they see different ranges of colour, or even only in black and white for example.

It's true that we can get the same or similar information from different sensory modalities, but the sensations themselves are different. All of that information falls inot the category of 'how things appear or present themselves to us'. — Janus

Then what is missing exactly if we know the way they see the world?

It seems natural to think that there must be more to things than just how they appear or seem to be. Of course we can never know more than that, but the fact that we are compelled to think of the 'in itself' has many ramifications for human life. Not in terms of something we know, but in terms of what we can never know. The knowledge here is just self-knowledge. — Janus

But I asked what a "thing in itself" even means. It sounds like a misuse of language. Does it mean to BE the thing in itself? If so, is there a BEING to a chair, table, house, car, or rock? If not then there is nothing missing.

As to our experience of mind I think this is a real minefield. If mind consists only in our experience and judgements would it follow that we know all there is to know about it? Psychedelics and altered states in general show that we have the potential for very different experiences, so it would seem presumptuous to imagine that we have explored all there is to know about what it is possible to experience. — Janus

So the thing in itself includes all states of the thing in the past, present or future? We don't see an apple on the table in the future. We see it in the present. We are talking about the thing in itself at this moment. I'm talking about the right here and now. Do you have direct access to your mind in it's current state? Are you experiencing your mind as "the thing in itself" at this moment?

Even with that said, we can make predictions and get at past causes by our present observations. If we get at the past causes and make accurate predictions, again - what is missing?

Then what is missing exactly if we know the way they see the world? — Harry Hindu

We infer the way they see the world. It doesn't follow that we can see the world that way.

But I asked what a "thing in itself" even means. It sounds like a misuse of language. Does it mean to BE the thing in itself? If so, is there a BEING to a chair, table, house, car, or rock? If not then there is nothing missing. — Harry Hindu

We don't know what things are apart from how they appear to us. Once that is realized it is possible to make the logical distinction between how things are for us, how they are for other animals and how they are in themselves. Some believe that physics shows us how things are in themselves, but the problem is there is no way to know if that is true, and anyway even the quantum physicists say that they can form no coherent picture of the quantum world and that understanding it is only possible via mathematics. What QM does seem to show is that things are not what they seem.

You just quoted the OP out of context, — Bob Ross

No, I didn't do that either.

The biggest problem for indirect realists (that's the title of your OP) is their own assumption that we never experience objects and states of affairs directly. How is knowledge possible even under such conditions? Hence the complexity of Kant's investigation, and its seemingly paradoxical use of two worlds or perspectives. Such problems don't even arise for direct realists or idealists.

Kant begins with the presupposition that our experience is representational and proceeds to correctly conclude that knowledge of the things-in-themselves is thusly impossible. — Bob Ross

Suppose I have a visual experience of shapes and colours. There is no doubt in my mind that this visual experience has been caused by something external to the visual experience itself. There is no doubt in my mind that this visual experience didn't cause itself.

It seems part of the a priori structure of the brain to expect that everything that happens has a cause. This cause may be called the thing-in-itself.

The next question is about the relation between my visual experience of a shape, for example, and the external cause of my experiencing this particular shape.

Either, the cause is identical to the effect, Direct Realism, or the cause is different to the effect, a representation, Indirect Realism.

But we only know the effect and can only reason about the cause.

For the Direct Realist, what information is there in an effect to be able to know its cause?

If it were possible to determine from an effect its cause, it would be possible to look at a broken window and know what caused it to break.

I don't quite get the problem. Let's say that there's something hiding under my bed cover. I cannot see under my cover to see what it is; I can only see the bump in the cover (and maybe the cover moving). Any knowledge I have of the thing under my cover is at best an inference.

It's the same principle with things like Kant's transcendental idealism or indirect realism.

And then on the further extreme the idealist claims that there isn't anything under my cover; there's only the cover, which happens to have a bump (and maybe is moving).

I apologize for the belated response! My schedule got hectic.

The way in which we know our own being, and the way we know the existence of other objects, is
different.

Correct. But:

I think that Kant agrees with Descartes that knowledge of our own being is apodictic i.e. it cannot plausibly be denied, as it is a condition of us knowing anything whatever (cogito ergo sum)

Kant clearly denies the cogito ergo sum argument, and argues in the CPR that we cannot know anything about the self as it is in-itself because our self-consciousness, albeit it different, is still representational. It is important to remember that Descartes was arguing for the self as a simple substance; and Kant was arguing for the self as the unity of apperception, which has transcendental validity insofar as it is necessary for constructing our conscious experience:

The proposition, “I think,” is, in the present case, understood in a problematical sense, not in so far as it contains a perception of an existence (like the Cartesian “Cogito, ergo sum”), ["I think, therefore I am."] but in regard to its mere possibility – for the purpose of discovering what properties may be inferred from so simple a proposition and predicated of the subject of it.
…
That the I or Ego of apperception, and consequently in all thought, is singular or simple, and cannot be resolved into a plurality of subjects, and therefore indicates a logically simple subject – this is self-evident from the very conception of an Ego, and is consequently an analytical proposition. But this is not tantamount to declaring that the thinking Ego is a simple substance – for this would be a synthetical proposition. The conception of substance always relates to intuitions, which with me cannot be other than sensuous, and which consequently lie completely out of the sphere of the understanding and its thought: but to this sphere belongs the affirmation that the Ego is simple in thought. It would indeed be surprising, if the conception of “substance,” which in other cases requires so much labour to distinguish from the other elements presented by intuition – so much trouble, too, to discover whether it can be simple (as in the case of the parts of matter) – should be presented immediately to me, as if by revelation, in the poorest mental representation of all.

– CPR: https://www.marxists.org/reference/subject/ethics/kant/reason/critique-of-pure-reason.htm#:~:text=That%20the%20I%20or,mental%20representation%20of%20all.

If all you are noting is that Kant believed that there must be something which exists which is producing the conscious experience which I have, then that is true; but this is not the same as the cogito argument (in its original argumentation).

This is critical because nothing I said that you quoted denies the ‘I’ as the unity of apperception; and Kant is denying any knowledge of the self as it is in-itself. So, the paradox again arises such that I cannot trust even my own internal sense to give me information about what I am in in-itself and yet I can trust it enough to know that I am at all—seems problematic, no?

An object with no definite properties is not an object at all. To be an object is to have properties.

My point was that that we could say there is an object, but nothing about what it is—nothing about its properties. I just worded that confusingly.

Again, the key difference about knowledge of objects, and knowledge of your own faculties

Hopefully the above helps clarify why this does not resolve the paradox. Viz., if you can trust your internal sense enough to give you accurate enough information to know you exist [with representative faculties], then you necessarily can know some information about how the world really is.

Kant doesn't speak of brains, neuroscience, genetics, etc. when making his case.
…
Kant's arguments are based on "what must be necessary for thought to exist as such."

That’s fair, I use those terms to explain it because it is easier to convey to other people. Most people have never heard of transcendental approaches to truth.

this is why the "paradox" shows up—it's the result of mixing Kant's conclusions with empiricist arguments about the way perception is shaped by biology, physics, etc.

Could you elaborate on this part? I still think there’s a paradox even if you speak in purely Kant’s terms. We only know that objects are a necessary precondition for our experience IF we trust our experience to some extent—which he then turns around and denies is possible. I think this might be, although I am not familiar with Hegel’s critique, what you are referring to with Hegel:

Now, the other thing you get at is that Kant does seem to dogmatically assume that perceptions are of objects. That's Hegel's big charge, worked out in the Logic. Hegel agrees that perceptions are of objects, but he thinks that starting out by presupposing this is how Kant ends up with the noumenal and his dualism problem.

This sounds like Hegel identified the paradox as “dualism problem”. How does Hegel resolve this issue then? That might help resolve it here.

In other words, the conception alone is not knowledge.

Hmmm, I don’t buy it. The concept of an apple is knowledge of what an apple is—that’s part of the whole idea of having a concept of an apple.

If I see a ball, I don’t call it either of those you mentioned. I call it a ball iff I already know it as such, or, if you inform me that’s what that thing I see, is.

That’s fair. Again, as I noted in your DM: that’s besides the point.

And I didn’t say whatever our brain says it is; I said whatever our understanding says it is, insofar as the faculty of understanding, in its full procedural operation, thinks, judges and cognizes….all those systemic artifices which are grounded in logic as opposed to being grounded in external reality and externally affected physiology, and internal reproductive imagination, re: intuition, the sum of which is called sensibility.

I get why you went that route, but wouldn’t you agree the brain is the representational knowledge of those faculties?

but does presuppose nonetheless, that the human individual is of such a nature as to have representational faculties imbued in a system by which any knowledge at all is possible.

But, then, you have to concede that you have to trust your conscious experience to derive that that experience is representational—no?

Otherwise, you are just blindly presupposing that objects effect our senses—there’s nothing, without the aid of experience, that can be used transcendentally to determine that.

I do not see all these claims as being about the world as it is in itself.

I can see that to some extent—e.g., the faculty of understanding is not a comment on what such exists as in reality as it is in-itself.

Could it be that the biggest problem for indirect realists, is being called indirect realists?

What would you call it, then?

There is no doubt in my mind that this visual experience has been caused by something external to the visual experience itself
…
It seems part of the a priori structure of the brain to expect that everything that happens has a cause. This cause may be called the thing-in-itself.

Assuming by thing-in-itself we mean the object qua itself (independently of our experience of it), it sounds like you are denying that you cannot have any knowledge of the things-in-themselves; which cannot be true if there is an a priori structure by which your brain intuits and cognizes objects (which you equally affirmed).

This doesn’t seem coherent to me.

The problem is that you have hidden the paradox, but it is there in your example. Either you trust the evidence you are using to infer whether or not there is such a thing under your bed, and what it is, or you do not. If you do, then you are trusting that evidence to give you accurate information about the "under the bed as it is in-itself": if you deny that have any such trustworthy evidence, then you have not reason to believe you can infer, other than blindly and absurdly, what is under there.

Sorry for the belated response!

I do not believe 1+1=2 is apriori for example.

The metaphysical underpinnings for “1 + 1 = 2” is that our brains construct our conscious experience according to math insofar as the plotting of objects in space is inherently mathematical.

Of course, the other alternative would be just say that math is a way that our over-arching faculty of reason nominally parses our conscious experience—which is the strongest version of mathematical anti-realism.

IE, that people are capable of doing logic is innate, but the practice of classical logic specifically must be learned.

That logic is a priori does not entail that we can perform, intellectually, logic properly since birth. These are separate considerations: the former is about how inherently logical our conscious experience is, the latter is about how logically sound our over-arching reason is at argumentation and reasoning.

Close, but not quite. A dog can experience a thing as well, but it cannot come up with the idea of "a thing in itself". That requires language, thinking, debate, etc. It is not an innate conclusion, but one of applied reason.

The point is that a thing-in-itself is the thing as it is in-itself: of course, it is a separate note that one may not have any self-reflective knowledge of it. Knowledge is, though, a requirement for cognition: your brain has to know how to do things and how to apply concepts and what not in order to construct the conscious experience you are currently having.

Since we can only observe representations, how do we know there's something under those representations? We only know because sometimes, the world contradicts our interpretations. Therefore the only logical thing we can conclude is that there must be something beyond our perceptions and interpretations that exists. Its not a proof of "I see the thing in itself" its a proof of, "Its the only logical conclusion which works."

Nothing about what we think is going to happen, self-reflectively, nor its contradiction entails that there is an object which impacted our senses (and of which we are experiencing). You seem to be conflating the faculties which produce our experience with our self-reflective knowledge of that experience. Viz., I may be wrong that this object next to be is red, but that my experience contradicts me is not the same as reality contradicting me.

To me, I would agree that the best explanation, given experience, is that there are objects impacting our senses: but that is derived from empirical data from (ultimately) our experience itself. E.g., I experience getting knocked out by a ball, I experience an optical illusion, I study biology, etc. This is not inherently a process of reality contradicting me: it is me confirming hypotheses through empirical study.

Its not necessarily about trust, its about experience. You and I have both had instances in our lives where our perceptions and beliefs about the world were contradicted in unexpected ways. Thus we conclude that there is something that exists apart from our understanding and perceptions.

Wouldn’t you agree that you have to trust your experiences, to some degree, to even posit that reality sometimes contradicts your perceptions?

Good discussion as usual Bob! I always like how you drill in. I'm heading out on vacation this week to Yellowstone park with some friends, so I won't be available to reply for a while. I'll read your reply when I get back for sure. Until then, stay great and I hope the discussion is interesting!

No worries at all!

The problem is that you have hidden the paradox, but it is there in your example. Either you trust the evidence you are using to infer whether or not there is such a thing under your bed, and what it is, or you do not. If you do, then you are trusting that evidence to give you accurate information about the "under the bed as it is in-itself": if you deny that have any such trustworthy evidence, then you have not reason to believe you can infer, other than blindly and absurdly, what is under there. — Bob Ross

I am able to believe that there is something under my covers without looking under my covers. I use what I can see to infer the existence of something that I cannot see. This is not a paradox or a contradiction or any sort of logical fallacy.

if we can trust our experience to tell us that we exist with other things in a reality — Bob Ross

We can only do this because it aligns with our experience. It poses no obstacle to indirect realism to use hte best of what we have.

I see @Michael is doing hte Lord's work already. Really telling how uncomfortable people are with the facts of perception.

So, the paradox again arises such that I cannot trust even my own internal sense to give me information about what I am in in-itself and yet I can trust it enough to know that I am at all—seems problematic, no? — Bob Ross

I don't know if it's problematic. I think we need to acknowledge the sense in which we are indeed 'a mystery to ourselves.' As I said, we know that we are, but it's quite conceivable that we don't fully understand what we are, and I don't see how that presents a paradox.

Hopefully the above helps clarify why this does not resolve the paradox. Viz., if you can trust your internal sense enough to give you accurate enough information to know you exist [with representative faculties], then you necessarily can know some information about how the world really is. — Bob Ross

Again Kant does not deny empirical realism. He qualifies it.

Assuming by thing-in-itself we mean the object qua itself (independently of our experience of it), it sounds like you are denying that you cannot have any knowledge of the things-in-themselves; which cannot be true if there is an a priori structure by which your brain intuits and cognizes objects (which you equally affirmed). This doesn’t seem coherent to me. — Bob Ross

Although Kant and Indirect Realism overlap, it gets confusing when both Kant and Indirect Realism are discussed alongside each other, even though the concept of Indirect Realism was around during Kant's lifetime.

Wikipedia Direct and Indirect Realism

In medieval philosophy, direct realism was defended by Thomas Aquinas. Indirect realism was popular with several early modern philosophers, including René Descartes, John Locke, G. W. Leibniz and David Hume.

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There’s one part of the whole transcendental idealism which poses a threat to the entire enterprise and of which I would like to explore with this forum: the paradoxical and necessary elimination of knowledge of the things-in-themselves via particular knowledge of thing-in-themselves — Bob Ross

You are correct in that as regards Kant and the CPR, the topic of things-in-themselves is a paradox. The CPR leaves us with the paradoxical nature of things-in-themselves, and in that sense the CPR is unsatisfactory, but that is how it is.

It is true that Kant in the CPR does try to justify transcendental knowledge in section B276 "the Refutation of Idealism" using the example of time, but his argument is unpersuasive

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

The word "transcendental" is a name not a description, and tells us nothing about the nature of transcendental knowledge. It doesn't even tell us that there is such a thing, in the same way that even though the name "unicorn" may exist in language, unicorns don't of necessity exist in the world. In the same way, if asked how to travel instantaneously through time and space, I can say through "wormholes". Naming something "transcendental knowledge" tells us neither whether it is possible in the first place nor even if it were possible how it is explained.

Kant in the CPR has no escape from this paradox, no explanation and no persuasive justification. Within the CPR, the thing-in-itself is a paradox and remains so

The problem is how to obtain a priori necessary knowledge from a posteriori contingent knowledge. Kant in the CPR says "transcendentally", but this is just a name, as "unicorns" and "wormholes" are just names not descriptions.
===============================================================================

To me, I would agree that the best explanation, given experience, is that there are objects impacting our senses: but that is derived from empirical data from (ultimately) our experience itself. — Bob Ross

As regards this topic, your position seems similar to Kant's

This is the problem. How to discover a priori necessary knowledge from a posteriori contingent knowledge.

Locke said we have innate knowledge, which Kant rejects.

Hume says our knowledge comes from the observation of the constant conjunction of a posteriori events, but this does not give us a priori necessary knowledge

Kant in the CPR developed Hume's idea, and said we have a priori necessary knowledge transcendentally from a posteriori contingent observations. But "transcendentally" is just a word and is meaningless in itself.

My belief is in "Innatism", the view that the mind is born with already-formed ideas, knowledge, and beliefs (Wikipedia Innatism), whereby my belief that my experiences have been caused by something else is part of the structure of my brain.

The problem with the CPR is that Kant doesn't explain how "transcendentally" is possible, leaving the paradox within the CPR of the possibility of knowledge about things-in-themselves.

Sorry for the belated response! — Bob Ross

No worry, I just got back a few days ago myself!

The metaphysical underpinnings for “1 + 1 = 2” is that our brains construct our conscious experience according to math insofar as the plotting of objects in space is inherently mathematical. — Bob Ross

Correct. That is an innate ability. But creating the symbol of '1' and base ten arithmetic are aposteriori.

Of course, the other alternative would be just say that math is a way that our over-arching faculty of reason nominally parses our conscious experience—which is the strongest version of mathematical anti-realism. — Bob Ross

No objections here. I think that works as well.

That logic is a priori does not entail that we can perform, intellectually, logic properly since birth. — Bob Ross

Correct. Logic proper must be learned through experience. The capacity to be able to learn and practice logic is innate. A fish cannot learn logic no matter how much it experiences.

The point is that a thing-in-itself is the thing as it is in-itself: of course, it is a separate note that one may not have any self-reflective knowledge of it. — Bob Ross

Agreed.

Knowledge is, though, a requirement for cognition: your brain has to know how to do things and how to apply concepts and what not in order to construct the conscious experience you are currently having. — Bob Ross

Belief is a requirement for cognition. Knowledge is a potential result of cognition.

Nothing about what we think is going to happen, self-reflectively, nor its contradiction entails that there is an object which impacted our senses (and of which we are experiencing). — Bob Ross

Correct. A thing in itself is not 'an object'. Its a logical concept. 'An object' is known by how it impacts our senses. Light reflects for sight, and air vibrations bounce for sound. 'A thing in itself' is the logical conclusion that there must be some reality that exists apart from our senses. Because we can only know 'objects' through our senses, we cannot know what a thing in itself is as 'an object' but only a logical concept.

You seem to be conflating the faculties which produce our experience with our self-reflective knowledge of that experience. Viz., I may be wrong that this object next to be is red, but that my experience contradicts me is not the same as reality contradicting me. — Bob Ross

No, I'm trying to note that there is belief and knowledge that is gained from the interpretation of our senses. I can 'see' red for example, but then notice the light wavelength is green. My senses experience red, but the reality is it is green. This is like a color blind person. Reality does not contradict my experience of red, only my interpretation that it is objectively red.

To me, I would agree that the best explanation, given experience, is that there are objects impacting our senses: but that is derived from empirical data from (ultimately) our experience itself. E.g., I experience getting knocked out by a ball, I experience an optical illusion, I study biology, etc. This is not inherently a process of reality contradicting me: it is me confirming hypotheses through empirical study. — Bob Ross

Correct. And the way it is confirmed is the fact that the interpretations are not contradicted. A 'thing in itself' is not an object though. It is the logical concept of an underlying reality that we can never fully know. 'An object' is part of the logical belief and knowledge system that is, or is not contradicted by reality. We use contradictions and lack of contradictions, because contradictions are the only true way we can asses whether we are at odds with reality. If there is no contradiction, then we cannot claim that we have affirmed the underlying reality, but that we are merely concurrent with it at some unknown level.

Wouldn’t you agree that you have to trust your experiences, to some degree, to even posit that reality sometimes contradicts your perceptions? — Bob Ross

Absolutely. But there is trusting your experiences, then trusting the beliefs and interpretation from those experiences. What you experience, is what you experience. It is our beliefs and interpretations of what that means in reality which is constantly circumspect. We only gain logical and emotional confidence in those interpretations when they are not contradicted.

It does not appear we are that far apart here on concepts, if at all!

The concept of an apple is knowledge of what an apple is—that’s part of the whole idea of having a concept of an apple. — Bob Ross

The whole idea of having, the only reason to have, a concept, is to represent that thing perceived, by a name. The name apple merely indicates how the thing perceived is to be known, which is called experience.

……wouldn’t you agree the brain is the representational knowledge of those faculties? — Bob Ross

I may be misunderstanding, but assuming I do, no, I would not agree. Faculties are function-specific members of a system described in a metaphysical theory. There’s no possible method by which those faculties can be found in a brain, they being merely logical constructs, and by the same token, there’s nothing empirically provable, hence nothing falsifiable, in a metaphysical theory. All that can be said, insofar as empirical verifications for non-empirical theories are out of the question, is the brain has nothing to do with abstract conceptions authorized by such theory.

So…what good is it, is the usual modern ask. It’s all we got to work with being the best answer.
—————-

…..you have to concede that you have to trust your conscious experience to derive that that experience is representational—no?….. — Bob Ross

All I have to trust is that my knowledge obtained at one time, does not contradict Nature in another time.

That my experiences are representational, or, that all my experiences are of only representations, is proved at sensibility, systemically long before the experience itself, therefore I have no need to trust them to prove their constituency.

…….Otherwise, you are just blindly presupposing that objects affect our senses—there’s nothing, without the aid of experience, that can be used transcendentally to determine that. — Bob Ross

Why do I have to presuppose that objects effect my senses, when my sensations apodeitically prove my senses have been affected? If I can see a mosquito bite me, if I can smell the bacon I hear frying, why do I have to presuppose either one of those objects?

And on the other hand, why subject myself to the absurdity of supposing what just bit me, or that stuff I’m about to consume, wasn’t an object at all?

There’s nothing that can be used transcendentally to determine…..what, that it is only objects that effect the senses? Why do we need a transcendental source to determine empirical circumstance? We may like a transcendental source for determining how empirical circumstances are possible, but the fact of sensation already proves it, so why bother?

I’m a little in the dark here, not sure how you arrive at the questions you ask.

Let's go down this path which you are describing: I think that will be beneficial. What about your perceptions do you think gives you accurate enough information to make an inference about reality as it is in-itself?

How can you know that you exist at all? That you exist itself also requires inherent trust of one's experience: we experience in a way where there seems to be an 'I' vs. 'other'.

Even the direct realist (if also a scientific realist) can believe in the existence of things that he cannot directly perceive (e.g. electrons and dark matter), and believe that these things are very unlike the things that he can directly perceive.

Whereas the direct scientific realist believes that his direct perception of a Geiger counter gives him reason to believe in the existence of radiation, the indirect realist believes that his direct perception of qualia/sense data/whatever gives him reason to believe in the existence of a Geiger counter.

Your reasoning as it stands applies to believing in anything that one cannot directly perceive, and so would call into question almost all of science (especially particle physics).

Or referring back to my original example, your reasoning would entail that it is irrational to believe that there is something moving under my bed covers.

Are you willing to commit to this?

Or referring back to my original example, your reasoning would entail that it is irrational to believe that there is something moving under my bed covers.

No it would not. I was trying to entertain your analogy to help further the discussion, but it is technically a bad analogy: it is already littered with phenomenal knowledge and requires no knowledge of the things-in-themselves. You would have to give an example which posits inferred knowledge of a thing-in-itself from phenomena to demonstrate your point: it is uncontroversially true that we can infer about phenomena, or possible phenomena, from given phenomena (such as a ball being under the bed without seeing it).

The epistemic dualism that inevitably arises in indirect realism is exactly because the very idea of a bed, covers, and something being underneath them is phenomenal; and once you strip away the a priori means of cognizing them, there is no intelligible “bed” nor “covers” left.

What you are trying to do, mistakenly, is claim that you can infer the things-in-themselves like how you can infer something phenomenally from other phenomena: these are not the same at all.

I have no problem with saying that I can infer about things as it relates to phenomena; but inferring about things-in-themselves from phenomena is a contradicto in adjecto.

Your reasoning as it stands applies to believing in anything that one cannot directly perceive, and so would call into question almost all of science (especially particle physics).

In the CPR, an object which our sensibility is incapable of sensing, or which our understanding is incapable of cognizing, are noumena: they are sub-species of things-in-themselves. Noumena are equally unknowable as any other things-in-itself: your sensibility, intuition, and cognition are only capable of knowing things as it is a priori structured to.

Now, if by science you are smuggling in scientific realism, then, yes, I think a transcendental idealist would have to be a scientific anti-realist of sorts; but this does not mean that science isn’t applicable to phenomena. In fact, that’s exactly what Kant argued—viz., science is grounded in a priori principles and of which are only universally true for human experience. That’s kind of the whole point Kant is trying to argue for: the synthesis of rationalism with British empiricism.

Even the direct realist (if also a scientific realist)

You are equivocating: one can be a direct realist without being a scientific realist. Every direct realist must be an empirical realist—albeit it rare, they could reject the scientific process of study. EDIT: Ignore this part: I read it wrong.

A thing in itself is not 'an object'. Its a logical concept.

A thing-in-itself is the concept of an object which we cannot know anything about: so it necessarily is an object. You make it sound like it is purely abstract: it is no more abstract than the concept of an object, which refers to a real object.

It seems like you agreed with me, so I am not following why you do not believe in a priori knowledge. If your representative faculties must already know how to do certain things and already has certain concepts at its disposal, then it must have a priori knowledge. Perhaps it has to do with:

Belief is a requirement for cognition. Knowledge is a potential result of cognition.

To keep things simple, let’s assume the traditional interpretation of knowledge: a justified, true belief.

You cognition must have more than a mere belief to know how to do what it does. E.g., your cognition has a priori knowledge on how to construct objects in space because it clearly does it correctly (insofar as they are represented with extension). The necessary precondition for the possibility of experiencing objects with extension is that your brain knows how to do that.

do you think gives you accurate enough information to make an inference about reality as it is in-itself? — Bob Ross

I'm conflicted. On the one hand, my understanding of hte physical elements of perception lend themselves to 'No'. But, my understanding of my experience in the round lends itself to 'yes'. However, I think 'common sense' is often not at all sensible and reject arguments of the likes of Searle and Austin which literally hand-wave these problems away. They seem to refuse to do philosophy when it comes to perception, and enquiring into their own (imo clearly erroneous) priors. They don't seem to even be priors - they wont tell us their priors!! LOL

So, I have to say i'm not entirely sure where i land here anymore. It's likely in the previous discussions I was dead-set on 'no'.

I am going to condense our conversation into one, to keep track of it better.

t’s affect is called sensation and its representation is called phenomenon, but the particular object itself, hasn’t yet been exposed to that part of the system which assigns conceptions. Which is to say, we don’t know yet what to think of that particular object impacting our senses.

This part is where you lost me. How is “its representation” not the end result of the judgments, concepts, and reason?

So even though the conscious subject to which experience belongs has no need to call the particular object that appears to the senses anything, insofar as he isn’t even conscious of the synthesis producing phenomena anyway, and to which Kant gives the term “…the undetermined object of empirical intuition…”, the system itself does need to call it something, in order for that which follows from it, to be a valid logical inference. As far as the system itself is concerned, then, to which being conscious or not has no meaning, that thing is called a transcendental object.

From my reading of CPR, the thing-in-itself is what impacts the senses.

Try thinking of phenomena as the signal traveling along nerves, say, output of the eye to the input to the brain. There is a signal, we have no awareness of it, but it is something, which we call intuition, and the information the signal carries represents whatever it was that impacted the sensory device to which the nerves connect, and that is called phenomenon.

This doesn’t seem coherent with Kant’s schema: Kant refers to what we end up seeing, hearing, etc. as phenomena. This is why I am trying to get you to answer what you call the end result which is a part of one’s experience; and I still have yet to hear an answer.

The whole idea of having, the only reason to have, a concept, is to represent that thing perceived, by a name. The name apple merely indicates how the thing perceived is to be known, which is called experience.

This is peculiar to me, as, then, the brain does not know the concept of quality; nor any of the twelve categories of the understanding—nor does the “understanding” if you want to avoid using the term “brain”.

I may be misunderstanding, but assuming I do, no, I would not agree. Faculties are function-specific members of a system described in a metaphysical theory. There’s no possible method by which those faculties can be found in a brain, they being merely logical constructs, and by the same token, there’s nothing empirically provable, hence nothing falsifiable, in a metaphysical theory. All that can be said, insofar as empirical verifications for non-empirical theories are out of the question, is the brain has nothing to do with abstract conceptions authorized by such theory.

Wouldn’t you agree, though, that the brain is the representation of the thing which has those faculties? It’s two sides of the same coin.

Why do I have to presuppose that objects effect my senses, when my sensations apodeitically prove my senses have been affected? If I can see a mosquito bite me, if I can smell the bacon I hear frying, why do I have to presuppose either one of those objects?

Because none of that is about things-in-themselves. If you agree that seeing a mosquito bite you indicates there is a mosquito, whatever it may be exactly, in reality in itself which impacted your senses; then you don’t believe we cannot know anything about things-in-themselves...for you just admitted that a mosquito is an animal which exists in reality in-itself.

And on the other hand, why subject myself to the absurdity of supposing what just bit me, or that stuff I’m about to consume, wasn’t an object at all?

Because the material world you experience is material because of the a priori way that you cognize it—re: space and time.

I don't understand what you're trying to argue here.

I am simply explaining that we very often, both in particle physics and everyday life, observe one thing to happen and then use that thing to infer the existence and behaviour of something else.

The direct scientific realist believes that such things as dark matter, gamma radiation, and electrons cannot be perceived directly, and can only be inferred by the effects that they have on the things that can be perceived directly.

The indirect realist believes the same thing, but just adds things like apples and chairs to the list of things that cannot be perceived directly.

It's the same reasoning for everyone, they just disagree on where the line is drawn. Is it at the mental/neurological/biological, or further beyond the body?

Wouldn’t you agree, though, that the brain is the representation of the thing which has those faculties? It’s two sides of the same coin. — Bob Ross

This is a really good point, just by the by, imo.

It points out the strict incoherence of referring to the organ of perception as anything more than a result of it's own function. Which is ... wild.

The indirect realist believes the same thing, but just adds things like apples and chairs to the list of things that cannot be perceived directly, and can only be inferred by the effects that they have on the things that can be perceived directly (which for them is something like qualia or sense data).

It's the same reasoning for everyone, they just disagree on where the line is drawn. — Michael

I think this is, perhaps, a little far, but given the point I've elucidated above I think its pretty clear that there is no line to draw, if we're going to accept that the organ/s of perception do not rise to the level of 'certainly extant as they are'.

How do we reconcile these problems as indirect realists that accept that our conscious experience is representational? If we do trust our conscious experience to tell us about the things-in-themselves to some extent (as a necessity and way out), then how do we determine the limits of what we can know about the things-in-themselves? If we don’t trust our conscious experience to tell us about the things-in-themselves to some extent, then what grounds do we have to accept Kant’s presupposition (that our experience is representational)? — Bob Ross

So, in other words the categories of understanding manifest in unique ways that tend to obviate necessity of a purely a priori noumenal conception.

How can you know that you exist at all? — Bob Ross

You have to exist to question it!

I think the point is that this is still, at base, an inference and not a certainty verified from without. There's no reflective way to ensure this is the case, despite it being logically required for the question to arise. Every body wins :P

Nonsense on stilts. It's like the schoolyard 'yeah prove it!' said to every question, and it doesn't rise to the level of philosophy.

Interesting fact: St Augustine anticipated Descartes' Cogito by several millenia:

But who will doubt that he lives, remembers, understands, wills, thinks, knows, and judges? For even if he doubts, he lives. If he doubts where his doubs come from, he remembers. If he doubts, he understands that he doubts. If he doubts, he wants to be certain. If he doubts, he thinks. If he doubts, he knows that he does not know. If he doubts, he judges that he ougth not rashly to give assent. So whoever acquires a doubt from any source ought not to doubt any of these things whose non-existence would mean that he could not entertain doubt about anything. — Augustine, On the Trinity 10.10.14 quoted in Richard Sorabji, Self, 2006, p.219