Can we know that something is unknowable?

[Robin]

In another thread, someone suggested that it is knowable that noumena are unknowable.

But if it were knowable that noumena were unknowable wouldn't that constitute something we knew about them?

That in turn would contradict the claim that they were unknowable.

Isn't it a bit like the claim "there is no truth"?

[Tsukasa Buddha]

No.

[Radrook]

In another thread, someone suggested that it is knowable that noumena are unknowable.

But if it were knowable that noumena were unknowable wouldn't that constitute something we knew about them?

That in turn would contradict the claim that they were unknowable.

Isn't it a bit like the claim "there is no truth"?

That's good point! If we don't know anything about the noumena how can we be absolutely sure it is unkowable!

[Lord Emsworth]

If something is unknowable you can hardly meaningfully refer to it, I'd think. What is unknowable?

[Radrook]

What lies beyond the distant bounderies of our visible detectable universe is presently referred to as unknowable.

[UndercoverElephant]

In another thread, someone suggested that it is knowable that noumena are unknowable.

But if it were knowable that noumena were unknowable wouldn't that constitute something we knew about them?

No. It's like saying "We don't know anything about what is beyond boundary X" and you replying with "Ah, but we know it's beyond boundary X!!!" If all you know about something is that you don't know anything about it then you still don't know anything about it.

Fred: I know nothing about God.
Bob: Ah, but you know you know nothing about God, so you know something about God! Ah-hah!! :rolleyes:

[X]

For something to be truly unknowable, one must have no knowledge of it.
Even of it's existence.

For example, to support a claim that God is unknowable, none must not know anything about God. Not even that there is a God. They should have no more knowledge of God than did the Native North Americans living 4,000 years ago.

[Erigena]

Something completely unknowable is something that cannot be measured based on any currently accepted scientific method.

[UndercoverElephant]

For something to be truly unknowable, one must have no knowledge of it.
Even of it's existence.

Which is why Schroedinger called Kant's noumena "an extravagance".

[Robin]

Which is why Schroedinger called Kant's noumena "an extravagance".
And why the Physicalists and Positivists called the concept superfluous.

[Robin]

No. It's like saying "We don't know anything about what is beyond boundary X" and you replying with "Ah, but we know it's beyond boundary X!!!" If all you know about something is that you don't know anything about it then you still don't know anything about it.
So what you are saying is that if I know that Y is outside the boundary of X then I know nothing of Y at all? Really?

"I know nothing of Scotland, I only know it is not in England". But if you knew nothing of Scotland you would not know it was not in England.
Fred: I know nothing about God.
I see, so you are telling me that the statement "I know nothing of X" means the same of "I know that X is not knowable?"

Really? Is that what a modern education in philosophy gets you?

[UndercoverElephant]

And why the Physicalists and Positivists called the concept superfluous.

Which causes a slight problem for the physicalists, since it effectively claims that consciousness is the only thing that exists. Doh!

[UndercoverElephant]

So what you are saying is that if I know that Y is outside the boundary of X then I know nothing of Y at all? Really?

"I know nothing of Scotland, I only know it is not in England". But if you knew nothing of Scotland you would not know it was not in England.


I would if I knew everywhere in England wasn't Scotland.

[Holler Hoojer]

This is a little trivial for philosophical discussion, I suppose, but I can say without equivocation that I cannot know the time in a location where I am not.

[Robin]

Which causes a slight problem for the physicalists, since it effectively claims that consciousness is the only thing that exists. Doh!
You still don't even understand the problem set out in the OP, do you?

[Robin]

This is a little trivial for philosophical discussion, I suppose, but I can say without equivocation that I cannot know the time in a location where I am not.
So do you then claim with the same lack of equivocation that you can know nothing at all about the time in a location where you are not.

If so, then how do you know that you cannot know the time in a location where you are not?

[Robin]

I would if I knew everywhere in England wasn't Scotland.
Then you would know something about Scotland - that it was not in England.

Also, how would you be able to determine of something "this is not Scotland", if you didn't know anything about Scotland?

[Darth Rotor]

In another thread, someone suggested that it is knowable that noumena are unknowable.

But if it were knowable that noumena were unknowable wouldn't that constitute something we knew about them?

That in turn would contradict the claim that they were unknowable.

Isn't it a bit like the claim "there is no truth"?
To admit ignorance is not the same as knowing. Your OP question looks to be self referential, (I think I used that term correctly, perhaps not). The question hinges upon assigning a value of knowledge when the original assigned value is ignorance. I don't see where you have an operation that changes the variable beyond an unsupported statement.

Is this an example of a bait and switch, or simply carelessness in assigning values to variables in a statement?

DR

[Robin]

If something is unknowable you can hardly meaningfully refer to it, I'd think. What is unknowable?
Yes, exactly.

If noumena are unknowable then any sentence that includes the word "noumena" would not be about noumena - including this sentence.

[Robin]

To admit ignorance is not the same as knowing.
I did not say that it was. To say that we know something is unknowable is not admitting ignorance, it is claiming knowledge.
Your OP question looks to be self referential, (I think I used that term correctly, perhaps not). The question hinges upon assigning a value of knowledge when the original assigned value is ignorance.
But as I pointed out the original assigned value is not ignorance.
I don't see where you have an operation that changes the variable beyond an unsupported statement.
Which statement do you say is unsupported?
Is this an example of a bait and switch, or simply carelessness in assigning values to variables in a statement?
No, you have simply misinterpreted the claim as an admission of ignorance. There is a difference between "I don't know X" and "I know X is unknowable".

[plumjam]

I'm amazed that this debate still goes on. Looks like none of you have been studying your Rumsfeld.

[Robin]

I'm amazed that this debate still goes on. Looks like none of you have been studying your Rumsfeld.
I take it you mean the Donald variety.

[RandFan]

I'm amazed that this debate still goes on. Looks like none of you have been studying your Rumsfeld.I know it sounds the same but I don't think the OP falls within what Rumsfeld was saying.

You don't know when you are going to die. That's a statement of fact and it is a known unknown. There could be things that could happen to you in your life that we can't even speculate about. That is a statement of fact. That is an unknown, that is, unknown. Water is composed of H20. That's a known known.

Rumsfeld is deserving of criticism for many things but that's not one of them and sadly it's indicative of how poorly the average person understands formal logic. That isn't even a tough one.

[Robin]

I don't recall that he actually went into known unknowables.

[RandFan]

I don't recall that he actually went into known unknowables.There's a wiki page for that too (http://en.wikipedia.org/wiki/Known_unknown).

[wexer9]

What about the Heisenberg Uncertainty Principle?

It states that we cannot know the precise values of certain physical quantities such as momentum and position at the same time.

Isn't that kind of saying that while the position of something is knowable, the momentum of it is definitely unknowable? And vice versa?

[hgc]

I did not say that it was. To say that we know something is unknowable is not admitting ignorance, it is claiming knowledge.
...


Depends on what is meant by "knowable."

On one hand, I know something about God as a cultural meme -- its history, its place in literature, speculation about biological sources for belief, etc.

But that's all about the idea of God. When it comes to the actual thing, I only have the idea as expressed in culture as a guide. And by the standard definition, its beyond what I consider to be reach of knowledge. Hence, the reality of God is unknowable to me. I also think it's unknowable to you, but that's just my opinion.

[Sefarst]

To admit ignorance is not the same as knowing. Your OP question looks to be self referential, (I think I used that term correctly, perhaps not). The question hinges upon assigning a value of knowledge when the original assigned value is ignorance. I don't see where you have an operation that changes the variable beyond an unsupported statement.

Is this an example of a bait and switch, or simply carelessness in assigning values to variables in a statement?

DR

I think this mostly nailed it and some other posts came close to explaining it. Unknowableness is a negative value and the OP is trying to assign a positive value to it.

Can I know anything about something that I, by definition, cannot know anything about? It's a paradox of grammar, not an actual philosophical one.

[Robin]

What about the Heisenberg Uncertainty Principle?

It states that we cannot know the precise values of certain physical quantities such as momentum and position at the same time.

Isn't that kind of saying that while the position of something is knowable, the momentum of it is definitely unknowable? And vice versa?
Do we know that we cannot know the precise values of certain physical quantities such as momentum and position at the same time?

According to Feynman's "Six Easy Pieces" we don't.

[Robin]

I think this mostly nailed it and some other posts came close to explaining it. Unknowableness is a negative value and the OP is trying to assign a positive value to it.
The claim to know that something is unknowable is not a negative value, it is a positive claim. "Unknowable" itself is a positive value. "Unknown" is a negative value, you are making the same mistake that UE and Darth Rotor made
Can I know anything about something that I, by definition, cannot know anything about? It's a paradox of grammar, not an actual philosophical one.
In which case please show me the grammatically correct version of the claim to know that noumena can't be known.

[Sefarst]

The claim to know that something is unknowable is not a negative value, it is a positive claim. "Unknowable" itself is a positive value. "Unknown" is a negative value, you are making the same mistake that UE and Darth Rotor made

In which case please show me the grammatically correct version of the claim to know that noumena can't be known.

If something is unknowable, it is, by definition, not part of the knowable.

Think of it like this. Everything knowable = A. Everything unknowable would therefore be everything outside of A (everything non-A). Ask yourself whether or not A can ever be non-A. It is excluded by definition.

[Robin]

Depends on what is meant by "knowable."

On one hand, I know something about God as a cultural meme -- its history, its place in literature, speculation about biological sources for belief, etc.

But that's all about the idea of God. When it comes to the actual thing, I only have the idea as expressed in culture as a guide. And by the standard definition, its beyond what I consider to be reach of knowledge. Hence, the reality of God is unknowable to me. I also think it's unknowable to you, but that's just my opinion.
It does depend upon what is meant by "knowable".

If by "it is known X is unknowable" we mean that it is known that there is nothing whatsoever that we can know about X then I think the statement is contradictory.

If we mean the precise answer to some particular question then it is not meaningless. For example if X is "whether the nth digit of a binary expansion of omega (for some specific n and omega)" then we can certainly know that we can't know the answer to that question.

On the other hand we know everything about X but not X itself.

[thull]

I still like the godel (http://2.bp.blogspot.com/_0V-b53pchC8/SAf4HTpnQ3I/AAAAAAAAAA4/v2jrgz4UzOI/s320/theorem-trees.jpg) picture regarding math knowledge. Just wish i could find a bigger picture online of it.

"Gödel basically proved that a formal system designed to encompass arithmetic cannot prove all arithmetic truths. There are unreachable truths that are beyond the formal system." cite (http://mathisliberalarts.blogspot.com/2008/04/graduate-seminar-topic-godels-theorems.html)

Figured since you already had Heisenberg and Feynman, i might as well add one more non-philosopher to the mix.

[Robin]

If something is unknowable, it is, by definition, not part of the knowable.

Think of it like this. Everything knowable = A. Everything unknowable would therefore be everything outside of A (everything non-A). Ask yourself whether or not A can ever be non-A. It is excluded by definition.
But are you saying that if I claimed to know that some B was not A, that I would not be making a positive claim?

[Roma]

Can we know something that is unknowable?

Can we see something that is unseeable?

Can we hear something that is unhearable?

Can we feel something that is unfeelable?

Can we answer something that is unanswerable? :rolleyes:

[Sefarst]

But are you saying that if I claimed to know that some B was not A, that I would not be making a positive claim?

A positive claim about a negative value. Like saying that God is non-existent. That would be a positive claim about a negative value, i.e. God's lack of existence.

[Robin]

I still like the godel (http://2.bp.blogspot.com/_0V-b53pchC8/SAf4HTpnQ3I/AAAAAAAAAA4/v2jrgz4UzOI/s320/theorem-trees.jpg) picture regarding math knowledge. Just wish i could find a bigger picture online of it.

"Gödel basically proved that a formal system designed to encompass arithmetic cannot prove all arithmetic truths. There are unreachable truths that are beyond the formal system." cite (http://mathisliberalarts.blogspot.com/2008/04/graduate-seminar-topic-godels-theorems.html)

Figured since you already had Heisenberg and Feynman, i might as well add one more non-philosopher to the mix.
And the example of a particular bit of the binary expansion of Omega is an example of an unreachable truth.

Here is where I had to amend my original claim - if we claimed that we can know nothing about these unreachable truths then we would be wrong - we know for example that they are unreachable.

But the claim that we know that we can't know what these actual truths are would be correct.

All in the definition of knowable.

[Robin]

A positive claim about a negative value. Like saying that God is non-existent. That would be a positive claim about a negative value, i.e. God's lack of existence.
OK, I am glad we have established that.

So if I claim that there is a B that is not part of A but also that B was part of A then would I not be contradicting myself?

[arthwollipot]

This is a little trivial for philosophical discussion, I suppose, but I can say without equivocation that I cannot know the time in a location where I am not.Oh, that's easy.

http://www.timezoneconverter.com/

Now, whether we can know the unknowable? Well, we can certainly know that there are unknowable things. The universal horizon is something like 14 billion light years away, give or take. That is how far light has had to travel since the beginning of the universe. Whatever is on the other side of that horizon is unknowable. We don't know whether it's just more universe, or whether the universe stops, or anything else about the region, because any signal we could possibly receive from there hasn't had enough time to get to us since the beginning of the universe. It is unknowable.

But at the same time, we can know that it is unknowable, by using logic - as I have just demonstrated.

Does the knowledge that something is unknowable consititute knowlege about that thing? It's a kind of second-order knowledge - metaknowledge. Is metaknowledge the same thing as knowledge? I suppose it all depends on your definition.

[Sefarst]

OK, I am glad we have established that.

So if I claim that there is a B that is not part of A but also that B was part of A then would I not be contradicting myself?

Every part of B that is A would fit as A and everything else would be non-A. If we say that C = attributes of B, we would say that "some C are A."

[rocketdodger]

If something is unknowable, it is, by definition, not part of the knowable.

Think of it like this. Everything knowable = A. Everything unknowable would therefore be everything outside of A (everything non-A). Ask yourself whether or not A can ever be non-A. It is excluded by definition.

Finally someone attempts to frame this issue formally. Thank you.

It doesn't illustrate what you want it to, though -- you have given no reason for why non-A is necessarily non-empty.

Formaly, the predicate Knowable will always be true and is therefore superfluous. Saying "X is knowable" is equivalent to saying "X" and saying "X is not knowable" is equivalent to saying "not X."

Since X is not a truth value -- rather, it is a constant -- negating it is a logically invalid operation. You can write out the symbols on paper but it might as well be a child's scribble since it has no meaning at all.

[Robin]

Every part of B that is A would fit as A and everything else would be non-A. If we say that C = attributes of B, we would say that "some C are A."
I see, so all knowable parts of unknowable things would be knowable?

[Robin]

Oh, that's easy.

http://www.timezoneconverter.com/

Now, whether we can know the unknowable? Well, we can certainly know that there are unknowable things. The universal horizon is something like 14 billion light years away, give or take. That is how far light has had to travel since the beginning of the universe. Whatever is on the other side of that horizon is unknowable. We don't know whether it's just more universe, or whether the universe stops, or anything else about the region, because any signal we could possibly receive from there hasn't had enough time to get to us since the beginning of the universe. It is unknowable.

But at the same time, we can know that it is unknowable, by using logic - as I have just demonstrated.

Does the knowledge that something is unknowable consititute knowlege about that thing? It's a kind of second-order knowledge - metaknowledge. Is metaknowledge the same thing as knowledge? I suppose it all depends on your definition.
But the claim that something was unknowable in the first place would also depend upon your definition of knowledge, so there is no basis for a distinction.

For example wouldn't you consider "on the other side of the event horizon" information about something?

[Robin]

Look at it this way, a common definition of if something is knowable is that a true and justified statement can be made about it.

So if I say "There is no true and justifiable statement that can be made about X" we need to ask, if that is a true and justifiable statement about X.

[slingblade]

Look at it this way, a common definition of if something is knowable is that a true and justified statement can be made about it.

So if I say "There is no true and justifiable statement that can be made about X" we need to ask, if that is a true and justifiable statement about X.

No. I think...

X and my knowledge of X are different things, just like dogs and my knowledge of dogs are different things. If I say I don't know anything about dogs, that's not information about dogs, is it? It's information about my knowledge.

That I know nothing about X speaks only to my knowledge.
It says nothing of the properties of X itself, or if X even has properties.
Which, of course, we don't know.

[JetLeg]

In another thread, someone suggested that it is knowable that noumena are unknowable.

But if it were knowable that noumena were unknowable wouldn't that constitute something we knew about them?

That in turn would contradict the claim that they were unknowable.

Isn't it a bit like the claim "there is no truth"?

It doesn't have to be, if noumena aren't completely unknowable. I don't think that anyone claims they are. For example, we _know_ that noumena aren't numbers. We _know_ that noumena aren't exempt from the rules of logic. I think we _know_ that noumena adhere to natural law (otherwise phenomena wouldn't adhere to natural law) and so on. But there is a certain aspect of the noumena that we don't know. You are right -> the issue is now to define this aspect more precisely !

[arthwollipot]

But the claim that something was unknowable in the first place would also depend upon your definition of knowledge, so there is no basis for a distinction.

For example wouldn't you consider "on the other side of the event horizon" information about something?Yes, but it's metaknowledge. It's not actually knowledge about something, it's knowledge about what we know about something.

Epistemology makes my head hurt.

[Richard Masters]

In another thread, someone suggested that it is knowable that noumena are unknowable.

But if it were knowable that noumena were unknowable wouldn't that constitute something we knew about them?

That in turn would contradict the claim that they were unknowable.

Isn't it a bit like the claim "there is no truth"?

I think what's tripping you up is the imprecise language.

[UndercoverElephant]

Can we know something that is unknowable?

Can we see something that is unseeable?

Can we hear something that is unhearable?

Can we feel something that is unfeelable?

Can we answer something that is unanswerable? :rolleyes:


I'm the world you'll never see
I'm the slave you'll never free
I'm the truth you'll never know
I'm the place you'll never go
I'm the sound you'll never hear
I'm the course you'll never steer
I'm the will you'll not destroy
I'm the gin in the gin-soaked boy, the gin-soaked boy...


http://www.youtube.com/watch?v=DXP1oLtPyDA

[Holler Hoojer]

So do you then claim with the same lack of equivocation that you can know nothing at all about the time in a location where you are not.

If so, then how do you know that you cannot know the time in a location where you are not?

No, please don't change my words. I said I could not know the time. I didn't say I knew nothing about the time; that, in fact, is a meaningless concept to me.

[Sefarst]

Finally someone attempts to frame this issue formally. Thank you.

It doesn't illustrate what you want it to, though -- you have given no reason for why non-A is necessarily non-empty.

Formaly, the predicate Knowable will always be true and is therefore superfluous. Saying "X is knowable" is equivalent to saying "X" and saying "X is not knowable" is equivalent to saying "not X."

Since X is not a truth value -- rather, it is a constant -- negating it is a logically invalid operation. You can write out the symbols on paper but it might as well be a child's scribble since it has no meaning at all.

The fact that I can write the symbols out demonstrates that, in my opinion, this is only a problem of language. If I replaced "knowable things" with some other item like "red things" there would be no problem. "Knowable" has epistemological implications, but linguistically, it's just another adjective. Formally, we can treat it like any other adjective and write it out, but in reality, the very definition of an unknowable thing is that you don't know it and therefore cannot say anything meaningful about it.

[rocketdodger]

No. I think...

X and my knowledge of X are different things, just like dogs and my knowledge of dogs are different things. If I say I don't know anything about dogs, that's not information about dogs, is it? It's information about my knowledge.

That I know nothing about X speaks only to my knowledge.
It says nothing of the properties of X itself, or if X even has properties.
Which, of course, we don't know.

Saying X is unknowable is a claim about X, not about knowledge of X. Saying property Y of X is unknown is a claim about knowledge of X. Big difference.

[rocketdodger]

The fact that I can write the symbols out demonstrates that, in my opinion, this is only a problem of language. If I replaced "knowable things" with some other item like "red things" there would be no problem. "Knowable" has epistemological implications, but linguistically, it's just another adjective. Formally, we can treat it like any other adjective and write it out, but in reality, the very definition of an unknowable thing is that you don't know it and therefore cannot say anything meaningful about it.

I consider the assertion of unknowability meaningful.

The only way a thing could be unknowable is if we never even think of it to begin with. That is why "unknowable" vs. "knowable" is an entirely useless distinction.

[UndercoverElephant]

I consider the assertion of unknowability meaningful.

The only way a thing could be unknowable is if we never even think of it to begin with. That is why "unknowable" vs. "knowable" is an entirely useless distinction.

That's not true. The example which spawned this thread is about Kant's noumena. The reasoning is as follows: even though we can only know phenomena, it is reasonable to assume that there must be something "behind the appearances" which causes them. Since they are behind the appearances, we can never know anything for sure about them. But if we deny they exist at all then aren't we running the risk of being left either defending solipsism or an extremely counter-intuitive version of idealism?

We have reason to think some sort of noumenal world exists even if we can never get beyond our experiences and know what that world is really like.

[rocketdodger]

That's not true. The example which spawned this thread is about Kant's noumena. The reasoning is as follows: even though we can only know phenomena, it is reasonable to assume that there must be something "behind the appearances" which causes them. Since they are behind the appearances, we can never know anything for sure about them. But if we deny they exist at all then aren't we running the risk of being left either defending solipsism or an extremely counter-intuitive version of idealism?

We have reason to think some sort of noumenal world exists even if we can never get beyond our experiences and know what that world is really like.

Well that is fine, but then you should be careful to qualify the use of "X is unknowable" with the fact that it doesn't mean "can't know anything about X" but rather "can't know certain things (in this case, nearly everything) about X."

I think the whole beef here (and I agree with the beef) is that saying "I can't know anything about X" isn't a valid sentence. Or, if it is, it is a human godel sentence, which humans can't parse anyway.

[Beerina]

I know it sounds the same but I don't think the OP falls within what Rumsfeld was saying.

You don't know when you are going to die. That's a statement of fact and it is a known unknown. There could be things that could happen to you in your life that we can't even speculate about. That is a statement of fact. That is an unknown, that is, unknown. Water is composed of H20. That's a known known.

Rumsfeld is deserving of criticism for many things but that's not one of them and sadly it's indicative of how poorly the average person understands formal logic. That isn't even a tough one.



"There are more things in Heaven and Earth, Horatio, than are dreamt of in your philosophy."

[Robin]

No. I think...

X and my knowledge of X are different things, just like dogs and my knowledge of dogs are different things. If I say I don't know anything about dogs, that's not information about dogs, is it? It's information about my knowledge.
But then again my knowledge of X and the knowability of X are different things again.
That I know nothing about X speaks only to my knowledge.
Of course is does. But the knowability of X speaks of X.

[Robin]

I think what's tripping you up is the imprecise language.
Explain.

[Robin]

That's not true. The example which spawned this thread is about Kant's noumena. The reasoning is as follows: even though we can only know phenomena, it is reasonable to assume that there must be something "behind the appearances" which causes them. Since they are behind the appearances, we can never know anything for sure about them. But if we deny they exist at all then aren't we running the risk of being left either defending solipsism or an extremely counter-intuitive version of idealism?

We have reason to think some sort of noumenal world exists even if we can never get beyond our experiences and know what that world is really like.
But as jetleg pointed out, if this is a meaningful concept then we know quite a good deal about noumena. If noumena are the something which causes phenomena then we know that noumena cause phenomena. We know that they are not exempt from logic or mathematics and we know that they are at least capable of instantiating algorithms and mathematically regular behaviour.

Even if I were the Solipsist then there would have to be some reason why these phenomena exhibited this regularity. Even in the most counter intuitive version of Idealism (a tautology?) there would have to be some reason.

[Richard Masters]

Explain.

Mine was a bit of a drive-by post, sorry. You wrote:


But if it were knowable that noumena were unknowable wouldn't that constitute something we knew about them?

That in turn would contradict the claim that they were unknowable.

Isn't it a bit like the claim "there is no truth"?

The contradiction arises depending on what you mean by noumena and unknowable. Most likely what is meant by unknowable is it cannot be experienced, whereas you might be (reasonably) interpreting it as just not knowable, or even "not referenceable".

Without knowing about the exact context, my guess is the contradiction arises from equivocation; as alluded to by your own signature.

[Alkatran]

It's been mentioned previously, but I want to try to say it better.

In math there are statements which have no definable truth value. There exist no possible proofs that they are true, and no possible proofs that they are false.

You have to decide if by knowable you mean knowing the statement itself, or knowing the truth value of the statement. If you mean knowing the statement, then all statements are knowable because you can enumerate them one by one. If you mean knowing the truth value, then only some of them are knowable.

[Soapy Sam]

I think words are supposed to be tools rather than traps.

[slingblade]

Traps are tools to the one who sets them.

[Richard Masters]

Rumsfeld is deserving of criticism for many things but that's not one of them and sadly it's indicative of how poorly the average person understands formal logic. That isn't even a tough one.

Agree 101%. And by that I mean 100%. :)

[Richard Masters]

Oh, that's easy.

http://www.timezoneconverter.com/

I prefer timeanddate.com :cool:

[Ichneumonwasp]

But isn't the claim "we cannot know x" really only a claim that we cannot know x in full? It isn't really a claim that we can know absolutely nothing about, say the nature of ultimate reality; or, at least, it shouldn't be.

We can know many things about reality because we can observe the interactions that constitute phenomena; but we cannot know fundamentally the full nature of the ur-substance (if there is such a thing) because there is nothing to which we may compare it and knowledge depends on comparison (it is the nature of how we know).

I think it is wrong to say that we can know nothing about some fundamental; it is more correct, I think, to say that we cannot fundamentally know what it *is*.

This is similar to the old metaphysical claim that God is unknowable, but the Medeival theologians still devised a via negativa, so the outlines of God could be glimpsed by knowing what he is not.

[Paul C. Anagnostopoulos]

Which causes a slight problem for the physicalists, since it effectively claims that consciousness is the only thing that exists. Doh!
I don't know what the Physicalists and Positivists actually said, but there is obviously something more than consciousness. Otherwise there would be nothing to keep the external world consistent.

~~ Paul

[Paul C. Anagnostopoulos]

That's not true. The example which spawned this thread is about Kant's noumena. The reasoning is as follows: even though we can only know phenomena, it is reasonable to assume that there must be something "behind the appearances" which causes them. Since they are behind the appearances, we can never know anything for sure about them. But if we deny they exist at all then aren't we running the risk of being left either defending solipsism or an extremely counter-intuitive version of idealism?
I don't see how solipsism is defensible at all if it claims there is nothing other than personal consciousness. If it does, it has no explanation for the consistency of the external world. I think the same goes for idealism.

There is clearly something going on over and above our own conscious experiences.

~~ Paul

[Paul C. Anagnostopoulos]

But as jetleg pointed out, if this is a meaningful concept then we know quite a good deal about noumena. If noumena are the something which causes phenomena then we know that noumena cause phenomena. We know that they are not exempt from logic or mathematics and we know that they are at least capable of instantiating algorithms and mathematically regular behaviour.
Donald Hoffman thinks phenomena are a user interface to noumena and that evolution makes no guarantee that noumena are anything at all like we perceive them. In fact, he thinks that evolution guarantees that they are not.

http://www.cogsci.uci.edu/~ddhoff/interface.pdf

~~ Paul