On 9/27/2011 5:28 AM, Jason Resch wrote:


On Tue, Sep 27, 2011 at 6:49 AM, Stephen P. King <stephe...@charter.net <mailto:stephe...@charter.net>> wrote:

    On 9/26/2011 7:56 PM, Jason Resch wrote:


    On Mon, Sep 26, 2011 at 12:14 PM, Stephen P. King <stephe...@charter.net
    <mailto:stephe...@charter.net>> wrote:

        On 9/26/2011 11:52 AM, Jason Resch wrote:


        On Mon, Sep 26, 2011 at 9:44 AM, Stephen P. King <stephe...@charter.net
        <mailto:stephe...@charter.net>> wrote:

            snip
            Jason,

                I really would like to understand how it is that the truth 
valuation
            of a proposition is not dependent on our knowledge of it can be 
used to
            affirm the meaning of the referent of that proposition independent 
of us?


        That sentence was hard to parse!  If I understand it correctly, you are 
asking
        how a truth, independent of our knowledge, can confer meaning to 
something
        without us?
        [SPK]
            Essentially, yes.



        Things unknown to anyone can have consequences which are eventually do 
make a
        difference to beings which are aware of the difference.  A comet 
colliding
        with the Earth and hitting a pond of unicellular organisms may have
        drastically altered the course of evolution on our planet.  That such a 
comet
        impact ocurred is a fact which is either true or false, despite it being
        independent of anyone's knowledge of it.  Yet it has perceptable 
results.

        [SPK]
            The web of causes and effects is an aspect of the material 
universe. I am
        taking that concept into consideration.


        Correspondingly, the existence of some mathematical truth (even if not
        comprehended by anyone) can have effects for observers, in fact, it 
might
        explain both the observers themselves and their experiences.
        [SPK]
            Slow down! "existence of some mathematical truth"??? Do you mean 
the truth
        value of some existing mathematical statement? That is what I mean in my
        question by the phrase "truth valuation of a proposition". Is a truth 
value
        something that exists or does not exist?


    I am not sure what you mean by "exists" in this case so let me say this, 
the state
    of being true, or the state of being false, for the proposition in 
question, was
    settled before a human made a determination regarding that proposition.

    [SPK]
        Is the "state of being true" a physical state, like the "state of 
having 10
    units of momentum"?


If the object under consideration is a physical object, you might be able to say that. If the object under consideration is 17, I would say no.

    Is there a "truth detector"?


There can be truth detectors, in some sense we may be truth detectors, but us discovery of a truth is not what makes it true.

    Are you sure that "state" and "true" are words that go together?


I am at a loss for an english word that conveys the status of true or false. We have the word parity for the status of even or odd, for example, but I could not think of such a word that conveys the same for true or false, which is why I used "the state of being true or false".

    AFAIK, true (or false) are values, like numbers. In fact logics can have 
truth
    values that range over any set of numbers. This puts truth valuations in 
the same
    category as numbers. No?


True and false can be represented by two different numbers, but I am not sure that makes them values in the same sense of numbers.



            How does the sentence "17 is prime is a true statement" confer 
implicit
            meaning to its referent?


What is the referent in this case? 17? And what do you mean by "meaning"? 17's primality is a fact of nature. The statement's existence or
        non-existence, comprehension or non-comprehension makes no difference 
to 17,
        only what you could say we humans have discovered about 17.

        [SPK]
            Is the symbol 17 the same extant as the abstract number it refers 
to?


    No, as I mentioned to Brent in a post the other day, we ought not confuse 
the label
    for the thing.  Nor should we confuse our idea of a thing for the thing 
itself.
    [SPK]
        OK, does not this imply that there are (at least) two separate 
categories:
    Labels and Things? What relation might exist between these categories?


Labels are a human invention to support communication of ideas, which you might say is yet another category of things.

The relation ship might be as follows: if I tell you to multiply 1200 x 1800, you could arrange 1800 rows of 1200 beans and count them all, or you could follow some simple rules of transformation applied to the labels '1200' and '1800' and have a shortcut to the answer, without having to do all that counting.


        Do you believe that symbols and what they represent are one and the 
same thing???


    No, we can apply some simple rules to the symbols in certain way to learn 
things
    about the object in question.
    [SPK]
        What relation might exist between the "rules" of symbols and the 
"rules" of things?


I think I covered this above.


        How does not the fact that many symbols can represent one and the same 
extant
        disprove this hypothesis? Is the word "tree" have a brownish trunk and 
greenish
        foliage?  What about the case where sets of symbols that have more than 
one
        possible referent? Consider the word FORD. Does it have wheels and a 
motor?
        What is the height of the water that one displaces when we might walk 
across
        it? There is a categorical difference between an object and its 
representations
        and the fact that one subobject of those categories exists is not proof 
that a
        subobject in another category has a given truth value. BTW, truth 
values are
        not confined to {True, False}.


    For well-defined propositions regarding the numbers I think the values are 
confined
    to true or false.

    Jason

--
    [SPK]
        Not in general, unless one is only going to allow only Boolean logics 
to exist.
    There have been proven to exist logics that have truth values that range 
over any
    set of numbers, not just {0,1}. Recall the requirement for a mathematical 
structure
    to exist: Self-consistency.


Okay, there may be other subjects, besides number theory and arithmetical truth where other forms of logic are more appropriate. For unambiguous propositions about numbers, do you agree with the law of the excluded middle?

Jason

I think this an assumption or another axiom. Consider the conjecture that every even number can be written as the sum of two primes. Suppose there is no proof of this from Peano's axioms, but we can't know that there is no proof; only that we can't find one. Intuitively we think the conjecture must be true or false, but this is based on the idea that if we tested all the evens we'd find it either true or false of each one. Yet infinite testing is impossible. So if the conjecture is true but unprovable, then it's undecidable.

Brent

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