I’m a transcendental idealist (which I don’t particularly like to say because the term sounds pretentious and a bit misleading). I get the impression that most philosophers, and moreover most scientists, don’t believe in it. I find it irresistable, and I’d like to hear some good arguments against it. By “good” I mean the following: written in understandable straight English, not fancy jargon out of the latest journals; not based on the fact that the idea was expounded in the olden days of the clockwork universe (“it’s wrong because it’s old”); and not based on dodgy things that have been dubiously derived from it, principally by C19 Germans.
I looked up transcendental idealism and got this from wiki (see: en.wikipedia.org/wiki/Transcendental_idealism):Transcendental idealism is a doctrine founded by German philosopher Immanuel Kant in the eighteenth century. Kant’s doctrine maintains that human experience of things is similar to the way they appear to us — implying a fundamentally subject-based component, rather than being an activity that directly (and therefore without any obvious causal link) comprehends the things as they are in and of themselves.
Basically, I like it; and I like Kant. This seems to be an epistomological view harking back to Plato and the Allegory of the Cave, where the ideal forms behind the fire cast their appearance shadows on the wall of the cave, just as our Kantian brain casts the phenomenal physical world of the senses out of the noumena – and mind, or Nous, must comprehend and interpret it. I like Plato in this sense also. In fact, I seem to remember some famous philosopher or two, starting with Santayana and including Alfred North Whitehead, saying that “All thought is nought but a footnote to Plato.”
I also like Whitehead’s philosophy of organism, that everything in the universe is, in some sense, alive and capable of ‘feeling.’ The
universe should be regarded as a single living organism. Many first peoples lived with this organic, holistic worldview and still do; and I think you’ll find that it is most compatible with transcendental idealism as well.
Science should seem pretty obvious. Science seeks objective knowledge of/about reality, and the objects therein. Thus, most are based on a supposition that perceived objects exist independent of the mind – what we perceive of an object describes the ‘thing-in-itself’, so to speak. That is to say, we can perceive, and therefore know, a ‘thing-in-itself’ as it exists independently of the mind. We are not limited to an understanding of only mental images, or interpretations, of perceived reality. This is a pretty big deal to many philosophers as well, from what I can tell.
The concept of the ‘Noumenon’, which was integral to Kant’s philosophy, is another widely criticized idea. I still don’t think I totally understand Kant’s usage of ‘noumena’, but the proposition that a ‘thing-in-itself’ does exist, yet is utterly unknowable aside from observation of how it manifests itself (as phenomena), is a bit hard to swallow. This renders the idea of the ‘noumenon’ indeterminate and thus unverifiable and/or falsifiable. A theory which is not falsifiable is not testable, and therefore not considered “scientific”. Even further, if the concept of the ‘noumenon’, or ‘thing-in-itself’, is to be posited as inherently unknowable in and of itself, we cannot hope to gain any real knowledge or truth by adopting such a belief.
There is no way to know what anything is independently of sense experience through the brain alone. Hence the concept of mind or nous. The ideal forms or noumena then exist a priori to their perceived physicalization through the senses. The Dich an Sich or thing-in-itself is that which is expressed or thought of as a sensory or perceptive object. Using a table, as Ding an Sich, as an example – this table is the noumenal or ideal table that every specific physical and phenomenal table is a special example of.
Also important to note and remember is that the endless possibility of perceptual error is a fact of life, just as there is always the possibility of error in interpretation. There is great irony and paradox here for one who presupposes no possibility of error in interpreting the world strictly through the subject-object dichotomy. How does that person know that that heuristic itself isn’t both an error and predicative of error itself? 
This is where, I think, many philosophers - like Aristotle - choose to differ. These ideal forms exist on a subjective basis, as ideas, meaning there actually exists no single ideal form. Like all other concepts, we end up with billions of different interpretations – the only thing linking them together is the designation and commonly perceived properties.
So, my question would be where, or on what level, do these ideal forms exist? Also, can everything be represented by an ideal form - is the scope of the ‘noumena’ indeterminate indeed? And lastly, if ‘noumena’ is to be regarded as a priori, where do we get this information from and why?
Agreed. However, I think people make this assumption subconsciously much of the time until something specific is called into question.
@ jonquil’s first post - good 
@ statiktech’s first post - sorry, but to me that sounds like you don’t know the difference between representations and objects therein on the one hand, and the thing-in-itself (das Ding an sich) on the other. Science describes objects within the human representation; even our paltry descriptions of the workings of the brain are within-representation.
@jonquil’'s and statiktech’s second post - I’m not really into Platonic Ideals, which I see as a made-up attempt at bridging the “vacuum” between thing-in-itself and representation.
What leads you to this conclusion? Apologies if my language is confusing, but I think I have some grasp of the difference. The ‘thing-in-itself’ being the “unknowable” objects that manifest as phenomena to be perceived. It is also thought to exist independently of the mind, or perception. Representations, on the other hand, are the perceived ideas by which we comprehend phenomena – this is both how the phenomena is represented to us as well as how we, ourselves, represent what we’ve experienced. Anywhere close?
Sure, but, again, the sciences often presuppose that our human representation actually reflects object reality, at least to some degree. The dichotomy between the phenomena and noumena is not useful for a scientist. I think most scientists would hold that both the ‘thing-in-itself’ and respective phenomena are knowable and perceivable as they are in and of themselves, and that there is no real distinction between the two. One of the goals of science is to bring our human representation ever closer to actual objective reality.
The thing-in-itself doesn’t “manifest as phenomena to be perceived”; it is the thing (and even using the word “thing” is misleading, but it’s the best we can do…) out of which consciousness springs.
Quite close actually. I think it’s best to start with the mental represenation (where else can one start, generally speaking?), to realise that it’s not a perception of things as they are in themselves, and finally to deduce the existence of the thing in itself. Schopenhauer says a lot of good stuff along these lines (before going off on a tangent).
This is the big mistake of the realist (as opposed to idealist) scientists. It is only phenomena (= the contents of our representations) that they deal with. The thing-in-itself should not concern them. The goal of science is to increase the range and resolution of our models of the physical universe (within our representations), and in this the human race has done and continues to do very well.
There’s quite a big difference, insofar as Plato urges us to get out of the cave and Kant says it’s impossible.
OK, my view: I’m not a fan of transcendental idealism. It was indisputably an important development historically and it contains some important insights and distinctions, though. But some of them have since been dented - see Quine’s “Two Dogmas of Empiricism” for a strong rejection of the analytic-synthetic distinction, for example. I also fail to see the value of the thing-in-itself as concept.
Since the 18th century philosophers and scientists have looked a lot more carefully at the language we use and the way our minds work. We’re not rational enlightenment machines simply struggling to overcome short-term emotions. It’s not wrong because it’s old, but its historical context is completely different and our understanding of the world has changed. Which is maybe a way of saying it’s wrong because it’s old, but a justified one 
TI (to me) makes a religious impulse of rationality. Useful philosophy to me starts from how things are, not how things Must Be. There are millenia of philosophers telling us how things Must Be, working from first principles, and none of them agree.
Kant’s morality is one of his weakest areas. The ‘categorical imperative’ is so context- and syntax-specific as to be useless, except as a tool to do what Kant is, and promote your inherent morality as Actually The Way All Rational Men Should Be. Schopenhauer’s, on the other hand, I have a lot of time for. It’s human.
Kant’s views simply segue off of Plato’s. It’s good to know the Platonic background for Kant’s TI.
I’m not sure what you mean by the “vacuum” between thing-in-itself and representation. The physical representation of the Ding an Sich necessarily holds the ideal form within it always.
This is not a discussion on morality but the nature of reality. In essence basically there is a reality and the reality, the former being the world of appearances, Kant’s phenomena, and the latter being the ideal a priori noumena of the things in themselves. An example would be the table as a representation of a table. It really does work, both then and now.
Do you mean a table as a representation of the table?
I’m not saying it’s wrong, it’s as assertion of how we can consider the world to be, that’s all. I don’t find it particularly useful.
You’ve pre-empted me well with that last line!
I’ll look up the Quine piece. I’m skeptical about overrating the importance of language in philosophy; my gut feeling is that it’s a playground for sophistry rather than a path to truth.
I start with “my world” which I deduce to be a representation. I then decide that there’s a distinction between repn and TI. I would thus describe myself as starting from How Things Are.
I daresay you’re right.
I withdraw that sloppy line…
The same is true of overrating reason. All things in balance
Exactly, there is a decision behind it! The difference between How Things Are and How I’ve Decided Things Are is very often elided, at least outside Pragmatist circles.
Okay, let’s use our brains less
This seems to me to be an instance of “the burden of proof is on the affirmer”. I think - interestingly - that idealists and realists could argue over who the affirmer is. The idealists (inc. me) say: we can’t know das Ding, therefore to assert anything about it is to be an affirmer, and is to require proof or evidence. But the realists say: the “null hypothesis” is to assume that das Ding is as similar as possible to the phenomenal world, and to reduce or modify this notion is to be an affirmer. Of course, I reject this null hypothesis, and maintain that the realists are the affirmers.
So even though I’m saying/deciding something about the world, it’s the least of an affirmation as possible, I like to think.
As I said before, there’s more to thinking than pure reason.
Interesting point. “We can’t know das Ding” is an assertion - “therefore to assert anything about it is to be an affirmer”. I think the assertion itself depends on what you consider under “know”, what your conditions for knowledge are.
Well, the first thing I “know” is my own subjective world. I start here, because everyone has to start somewhere, and the fact that every possible starting point can be criticised doesn’t put me off. And regarding affirmation/assertion, you make a valid point that any statement can be considered such (pedantic as that may sometimes be). I can only repeat myself, and hope that others understand me. And I maintain that realist affirmations about das Ding are a lot harder to justify than mine.
You can justify an affirmation of, or belief in, something that is inherently “unknowable”? The assertion that something is unknowable, yet known to exist seems contradictory to begin with. How does one justify something like this without immediately resorting to personal beliefs?
I don’t start with das Ding; rather, I start by deciding that the world I perceive is a representation. This begs the question: representation of what? Das Ding is the answer. It is thus arrived at indirectly, and is the necessarily problematic flipside of the perfectly comprehensible statement “my world is representation”. We can do no more than assign a name to this thing-which-is-represented.
You know, if I was fanatical about never saying anything remotely doubtful or misleading, I’d consider never explicitly mentioning das Ding an sich. After the statement “my world is representation” I’d shut my mouth (which certain people in the world would probably appreciate!).
OK, but why is Das Ding the answer? Why is this a better conclusion than our perspectives being representations of reality as it is?
I believe our perspectives are the representations. What leads you to conclude that the world you perceive is a representation of itself? What is the purpose or practicality in such a belief?