True Belief and Knowledge

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Reply Mon 23 Nov, 2009 09:45 am
Theaetetus;105076 wrote:
But doesn't a truth presuppose that it is true? Whether it is contingent or not is irrelevant because it must be true to be a truth.



I think you hit on something that is interesting to say the least--especially considering my response to ACB. There are many different ways to classify thinks as true. There are those things that are true to the individual and whether they are actually true or not is irrelevant. Then there are those things that are true according to a group of people. But then there are those things that are true independent of people. For example, the earth exists is independent of any human or group of humans. The universe exists is another. What this means is that as far as we know, nearly all truths are contingent truths that require individuals or groups of individuals to declare them true through their acceptance.

Looking at the Meno, and the other related dialogues, it is obvious that Plato was trying to transcend this and find a way to make contingent truths something that was grounded beyond the yea-sayers. Thus, the forms.


Of course, if a proposition is true, then it is true. That is just a tautology, and a necessary truth. But that does not imply that a true proposition cannot be false. It is true that Quito is the capital of Ecuador, but that does not mean that it is impossible that a different city in Ecuador is the capital (say Guyaquil). We have to distinguish between two different statements:

1. Necessarily, if p is true, then p is true. And,
2. If p is true, then p is necessarily true.

1. is, of course, as I wrote, a necessary truth and a tautology. But 2. is just false since it implies there are no contingent truths, and that is false. You have to watch where you place that term, "necessarily". since it never follows that because p is believed to be true that it is true.

The sentence "p is true to" (the individual, or the group) means no more then that the individual or the group believes that p is true. It leaves it open whether p is true or not. It doesn't matter to the truth of any proposition that anyone believes it is true. And, similarly, it does not matter to whether p is true or not whether p is accepted as true or not. "Accepted as true" is just a synonym for "believed true".
 
Emil
 
Reply Mon 23 Nov, 2009 10:39 am
@kennethamy,
kennethamy;105386 wrote:
Of course, if a proposition is true, then it is true. That is just a tautology, and a necessary truth. But that does not imply that a true proposition cannot be false. It is true that Quito is the capital of Ecuador, but that does not mean that it is impossible that a different city in Ecuador is the capital (say Guyaquil). We have to distinguish between two different statements:

1. Necessarily, if p is true, then p is true. And,
2. If p is true, then p is necessarily true.

1. is, of course, as I wrote, a necessary truth and a tautology. But 2. is just false since it implies there are no contingent truths, and that is false. You have to watch where you place that term, "necessarily". since it never follows that because p is believed to be true that it is true.

The sentence "p is true to" (the individual, or the group) means no more then that the individual or the group believes that p is true. It leaves it open whether p is true or not. It doesn't matter to the truth of any proposition that anyone believes it is true. And, similarly, it does not matter to whether p is true or not whether p is accepted as true or not. "Accepted as true" is just a synonym for "believed true".


More reading here about modal fallacies like the one mentioned above. That one is called the modal fallacy since it is so common.

What about this?:[INDENT]Someone believes this sentence (/proposition).
[/INDENT]Is it not true just when someone believes it? Indeed. So "since it never follows that because p is believed to be true that it is true." is false but it is generally true. (And more than generally true, it is true for virtually all propositions except those similar to the above, if any.)
 
kennethamy
 
Reply Mon 23 Nov, 2009 11:21 am
@Emil,
Emil;105401 wrote:
More reading here about modal fallacies like the one mentioned above. That one is called the modal fallacy since it is so common.

What about this?:[INDENT]Someone believes this sentence (/proposition).
[/INDENT]Is it not true just when someone believes it? Indeed. So "since it never follows that because p is believed to be true that it is true." is false but it is generally true. (And more than generally true, it is true for virtually all propositions except those similar to the above, if any.)


What sentence are you talking about?
 
Emil
 
Reply Mon 23 Nov, 2009 11:24 am
@kennethamy,
kennethamy;105412 wrote:
What sentence are you talking about?


I don't know what you mean.
 
kennethamy
 
Reply Mon 23 Nov, 2009 11:29 am
@Emil,
Emil;105415 wrote:
I don't know what you mean.


Someone believes this sentence (/proposition).
 
Emil
 
Reply Mon 23 Nov, 2009 01:13 pm
@kennethamy,
kennethamy;105419 wrote:
Someone believes this sentence (/proposition).


I meant the very same sentence. Here is a clearer example:
[INDENT]S. Someone believes the proposition expressed by (S) to be true.
[/INDENT]This is true only in case someone believes it to be true. That is impossible according to what you wrote:
[INDENT][...] "it never follows that because p is believed to be true that it is true."[/INDENT]
 
kennethamy
 
Reply Mon 23 Nov, 2009 03:01 pm
@Emil,
Emil;105427 wrote:
I meant the very same sentence. Here is a clearer example:[INDENT]S. Someone believes the proposition expressed by (S) to be true.
[/INDENT]This is true only in case someone believes it to be true. That is impossible according to what you wrote:[INDENT][...] "it never follows that because p is believed to be true that it is true."[/INDENT]


But what is the proposition expressed by (S)? Is there such a proposition?
 
Emil
 
Reply Wed 25 Nov, 2009 03:41 pm
@kennethamy,
kennethamy;105444 wrote:
But what is the proposition expressed by (S)? Is there such a proposition?


Presumably there is. Unless you want to ban self-reference or something like that. Is that how you get around liar paradoxes?
 
kennethamy
 
Reply Wed 25 Nov, 2009 04:28 pm
@Emil,
Emil;105917 wrote:
Presumably there is. Unless you want to ban self-reference or something like that. Is that how you get around liar paradoxes?


That is a way. There is a question as to what "this statement" refers to.
 
Emil
 
Reply Wed 25 Nov, 2009 07:49 pm
@kennethamy,
kennethamy;105924 wrote:
That is a way. There is a question as to what "this statement" refers to.


I think it is implausible. I've been reading up on dialetheism. Very exciting stuff. Not to be dismissed easily.

"this statement" (or "this proposition" refers to whatever proposition expressed by the very sentence. Do you think that is a problem? It does not seem so to me.
 
kennethamy
 
Reply Wed 25 Nov, 2009 09:47 pm
@Emil,
Emil;105967 wrote:
I think it is implausible. I've been reading up on dialetheism. Very exciting stuff. Not to be dismissed easily.

"this statement" (or "this proposition" refers to whatever proposition expressed by the very sentence. Do you think that is a problem? It does not seem so to me.


So, by substitution, "this proposition is false" means, ' "This proposition is false" is false'. And you claim to know what that means? Which is to ask, whether you claim to know what are its truth conditions?
 
Emil
 
Reply Wed 25 Nov, 2009 11:41 pm
@kennethamy,
kennethamy;105997 wrote:
So, by substitution, "this proposition is false" means, ' "This proposition is false" is false'. And you claim to know what that means? Which is to ask, whether you claim to know what are its truth conditions?


What kind of substitution is that?
 
Reconstructo
 
Reply Tue 1 Dec, 2009 05:26 pm
@kennethamy,
This sentence is a paradox.
 
kennethamy
 
Reply Tue 1 Dec, 2009 06:42 pm
@Emil,
Emil;106024 wrote:
What kind of substitution is that?


Substituting,"this sentence is false" for, "this sentence", of course. Isn't what "this sentence" is referring to?
 
Reconstructo
 
Reply Tue 1 Dec, 2009 06:47 pm
@kennethamy,
Am I witnessing a logic-chopper showdown? Persuade away, my friends.

Smile
 
Emil
 
Reply Wed 2 Dec, 2009 06:11 am
@kennethamy,
kennethamy;107418 wrote:
Substituting,"this sentence is false" for, "this sentence", of course. Isn't what "this sentence" is referring to?


Alright. Yes, I claim to know what that means. Banning self-reference is not very straightforward. You would have to ban sentences such as this too:
[INDENT]The proposition expressed by this sentence is true.
[/INDENT]Which is not paradoxical.

And the proponent of banning self-reference have explaining to do. Why are all self-referential sentences bad? It seems to me to be overkill and ad hoc.

I don't have any preferred solution, but dialetheism is very interesting.
 
Fido
 
Reply Wed 2 Dec, 2009 06:35 am
@Emil,
Emil;105427 wrote:
I meant the very same sentence. Here is a clearer example:
[INDENT]S. Someone believes the proposition expressed by (S) to be true.
[/INDENT]This is true only in case someone believes it to be true. That is impossible according to what you wrote:
[INDENT][...] "it never follows that because p is believed to be true that it is true."
[/INDENT]

You are talking about an ideal world with ideas... The fact is that truth as a form is also a form of relationship, and this because we learn it to share it for the benefit of others, but also must recognize the many times in history when people were asked to deny the truth in order to avoid death or remain as members of their societies... Socrates and Galileo come to mind here...Even Copenicus who dedicated the Revolution of the Spheres to the pope tiptoed into the truth, and at an advanced age where speaking the truth could not longer harm him...The truth should help all people, but what all people fear is change and nothing changes reality so quickly as the truth, and perhaps worst of all, is that our sense of truth we incorporate into our identities, so any new version of truth causes a re-examination of ourselves...

For example; I think a lot of people accept the theory of evolution as fact and go to churches that preach creationism.... They do not want to confront the contradictions but manage to wall off one version of truth from another...In Western history the dialectic which the Greeks used to determine truth- the middle ages used to resolve contradictions, especially in the Roman Law of Justinian...

Any one who dares to seek the truth should recognize the danger... We think of truth as good, but it often disrupts society and gets people killed...People can only handle a small dose at a time, so there is socially responsible truth, and there is wildly dangerous truth...Since no one can know the whole truth why make a bone of contention of it????Say something once; Why say it again???
 
kennethamy
 
Reply Wed 2 Dec, 2009 06:51 am
@Emil,
Emil;107525 wrote:
Alright. Yes, I claim to know what that means. Banning self-reference is not very straightforward. You would have to ban sentences such as this too:[INDENT]The proposition expressed by this sentence is true.
[/INDENT]Which is not paradoxical.

And the proponent of banning self-reference have explaining to do. Why are all self-referential sentences bad? It seems to me to be overkill and ad hoc.

I don't have any preferred solution, but dialetheism is very interesting.


I think that sentence has no subject. (I mean, "The proposition expressed by this sentence is true.").

I did not say that all self-reference is bad. I think we have to examine the particular case.

dialetheism is very interesting.

I am sure it is. So is Spinoza.
 
Emil
 
Reply Thu 3 Dec, 2009 06:08 am
@kennethamy,
kennethamy;107527 wrote:
I think that sentence has no subject. (I mean, "The proposition expressed by this sentence is true.").

I did not say that all self-reference is bad. I think we have to examine the particular case.


Alright. What makes the sentence above bad?

Presumably, the sentence expresses a proposition. You'd need to explain why it doesn't. It seems so much like other sentences that do express propositions.

Quote:
I am sure it is. So is Spinoza.


Graham Priest is the most known defender of it. Maybe you should give his book a read. It's called In Contradiction.

I don't know about Spinoza. I don't read anything that old.
 
kennethamy
 
Reply Thu 3 Dec, 2009 07:02 am
@Emil,
Emil;107786 wrote:
Alright. What makes the sentence above bad?

Presumably, the sentence expresses a proposition. You'd need to explain why it doesn't. It seems so much like other sentences that do express propositions.



Graham Priest is the most known defender of it. Maybe you should give his book a read. It's called In Contradiction.

I don't know about Spinoza. I don't read anything that old.


I said that I don't think that sentence has a logical subject.

If I thought the sentence expressed a proposition I would not be making these objections.

I guess I should. But the belief that some contradictions are true goes against my religion (sanity).

As I pointed out with the example of Spinoza, it does not follow from the fact that something is interesting, that Emil will read it.
 
 

 
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