Valid arguments preserve truth as good freezers preserve food.

On Jan 25, 12:53 pm, "Immortalist" <reanimater_2...@yahoo.com> wrote:

Is Validity Just a Hypothetical or Conditional Characteristic?

No; there are also valid formulas - propositional forms that are true
in all states of affairs. The most famous two are Aristotle's axioms:
~(A & ~A) and (A v A). Most valid wff, though, are conditionals; ar

A deductive argument is said to be sound when the premises of the
argument are true and the argument is valid.

Saying that an argument is valid is
equivalent to saying that it is
logically impossible that the
premises of the argument are
true and the conclusion false.

A less precise but intuitively clear way of putting this is to say
that, in a valid argument, if the premises are true, then the
conclusion must be true.

If the premises

1. If everything is caused,
then no one acts freely. and

2. Everything is caused.

are both true, then it must also be true that

3. No one acts freely.

As a simple matter of logic, it is impossible that premises (1) and (2)
should both be true and conclusion (3) be false. It is important to
notice that the fact that this argument is valid does not prove that
the conclusion is true. Validity is a hypothetical or conditional
characteristic; it assures us that the conclusion of the argument is
true if the premises are...

...If an argument can be valid and yet have a preposterously false
conclusion, what good is validity? Why should we be concerned with
validity at all? The answer is that a valid argument is
truth-preserving. Truth in the premises of a valid argument is
preserved in the conclusion. Of course, if the premises are not true to
begin with, then even a valid argument cannot ensure that the
conclusion is true. But only valid arguments are truth-preserving. An
analogy might help to clarify this point. Roughly;

Valid arguments preserve truth as
good freezers preserve food.

If the food you place in a freezer is spoiled to begin with, then even
a good freezer cannot preserve it. But if the food placed in a good
freezer is fresh, then the freezer will preserve it. Good freezers and
valid arguments preserve fresh food and truth, respectively. But, just
as the former cannot preserve food when the food is spoiled, so the
latter cannot preserve truth when the premises are false. Garbage in,
garbage out. Nevertheless, food freezers and valid arguments are worth
having because they do preserve something good when one has it, and
without them one may wind up with something rotten even when beginning
with something impeccable. Thus, validity is to be desired and
invalidity is to be eschewed.

Philosophical Problems and Arguments: An Introduction
by James W. Cornman, Keith Lehrer, George Sotiros Pappashttp://www.amazon.com/exec/obidos/tg/detail/-/0872201244/http://hume....In the propositional calculus, there are also valid formulas:
propositional forms that are true in all possible states of affairs.
The two most famous are Aristotle's axioms: ~(A & ~A) [Law of
Non-Contradiction] and (A v A) [Law of Excluded Middle. Most valid
wff, though, are conditionals. For instance, the valid formula that
correspond to modus ponens is (P -> ((P -> Q) -> Q). What ties the two
notions of validity together is the Deduction Theorem, by which every
valid argument has a valid corresponding conditional.- Hide quoted text -- Show quoted text -

On Thu, 25 Jan 2007 09:53:50 -0800, Immortalist wrote:
Valid arguments preserve truth as good freezers preserve food.I partially disagree with this.

There are two things you are talking about here. The first is the If/Then
process of logic. However this is separate from the content of the
argument so a false premise can be preserved by a correct argument.

So, let's say:
' 1. If everything is caused,..'

.... might have a different outcome if 'If everything is reaction,..'
started the ball rolling. Or 'If everything causes everything... etc

Same with 'If everything is made by (my own) God,..', as another example.

So the mechanics of process can preserve falsehoods also.

What is preserved that is 'truth' is the process itself but that's all.
Kinda like measuring the distance between two points does not validate
distance but rather the notched stick that is being used.

On Jan 25, 8:37 pm, "George Dance" <georgedanc...@yahoo.ca> wrote:
On Jan 25, 12:53 pm, "Immortalist" <reanimater_2...@yahoo.com> wrote:

Is Validity Just a Hypothetical or Conditional Characteristic?

No; there are also valid formulas - propositional forms that are true
in all states of affairs. The most famous two are Aristotle's axioms:
~(A & ~A) and (A v A). Most valid wff, though, are conditionals; ar


No, it is important to notice that the fact that an argument is valid
does not prove that the conclusion is true. Validity is a hypothetical
or conditional characteristic

it simply assures us that the conclusion
of the argument is true if the premises are and no valid formula makes
falshoods true, at least that I know of.

If the premises are not true to begin with, then even a valid argument
cannot ensure that the conclusion is true. But only valid arguments are
truth-preserving.





A deductive argument is said to be sound when the premises of the
argument are true and the argument is valid.

Saying that an argument is valid is
equivalent to saying that it is
logically impossible that the
premises of the argument are
true and the conclusion false.

A less precise but intuitively clear way of putting this is to say
that, in a valid argument, if the premises are true, then the
conclusion must be true.

If the premises

1. If everything is caused,
then no one acts freely. and

2. Everything is caused.

are both true, then it must also be true that

3. No one acts freely.

As a simple matter of logic, it is impossible that premises (1) and (2)
should both be true and conclusion (3) be false. It is important to
notice that the fact that this argument is valid does not prove that
the conclusion is true. Validity is a hypothetical or conditional
characteristic; it assures us that the conclusion of the argument is
true if the premises are...

...If an argument can be valid and yet have a preposterously false
conclusion, what good is validity? Why should we be concerned with
validity at all? The answer is that a valid argument is
truth-preserving. Truth in the premises of a valid argument is
preserved in the conclusion. Of course, if the premises are not true to
begin with, then even a valid argument cannot ensure that the
conclusion is true. But only valid arguments are truth-preserving. An
analogy might help to clarify this point. Roughly;

Valid arguments preserve truth as
good freezers preserve food.

If the food you place in a freezer is spoiled to begin with, then even
a good freezer cannot preserve it. But if the food placed in a good
freezer is fresh, then the freezer will preserve it. Good freezers and
valid arguments preserve fresh food and truth, respectively. But, just
as the former cannot preserve food when the food is spoiled, so the
latter cannot preserve truth when the premises are false. Garbage in,
garbage out. Nevertheless, food freezers and valid arguments are worth
having because they do preserve something good when one has it, and
without them one may wind up with something rotten even when beginning
with something impeccable. Thus, validity is to be desired and
invalidity is to be eschewed.

Philosophical Problems and Arguments: An Introduction
by James W. Cornman, Keith Lehrer, George Sotiros Pappashttp://www.amazon.com/exec/obidos/tg/detail/-/0872201244/
http://hume...

In the propositional calculus, there are also valid formulas:
propositional forms that are true in all possible states of affairs.
The two most famous are Aristotle's axioms: ~(A & ~A) [Law of
Non-Contradiction] and (A v A) [Law of Excluded Middle. Most valid
wff, though, are conditionals.

For instance, the valid formula that
correspond to modus ponens is (P -> ((P -> Q) -> Q). What ties the two
notions of validity together is the Deduction Theorem, by which every
valid argument has a valid corresponding conditional.- Hide quoted text -- Show quoted text -

On Jan 25, 8:37 pm, "George Dance" <georgedanc...@yahoo.ca> wrote:
On Jan 25, 12:53 pm, "Immortalist" <reanimater_2...@yahoo.com> wrote:

Is Validity Just a Hypothetical or Conditional Characteristic?

No; there are also valid formulas - propositional forms that are true
in all states of affairs. The most famous two are Aristotle's axioms:
~(A & ~A) and (A v A). Most valid wff, though, are conditionals;


No, it is important to notice that the fact that an argument is valid
does not prove that the conclusion is true.

Validity is a hypothetical
or conditional characteristic; it simply assures us that the conclusion
of the argument is true if the premises are

and no valid formula makes
falshoods true, at least that I know of.

If the premises are not true to begin with, then even a valid argument
cannot ensure that the conclusion is true. But only valid arguments are
truth-preserving.


Philosophical Problems and Arguments: An Introduction
by James W. Cornman, Keith Lehrer, George Sotiros Pappashttp://www.amazon.com/exec/obidos/tg/detail/-/0872201244/http://hume....

For instance, the valid formula that
correspond to modus ponens is (P -> ((P -> Q) -> Q). What ties the two
notions of validity together is the Deduction Theorem, by which every
valid argument has a valid corresponding conditional.

Immortalist wrote:

On Jan 25, 8:37 pm, "George Dance" <georgedanc...@yahoo.ca> wrote:
On Jan 25, 12:53 pm, "Immortalist" <reanimater_2...@yahoo.com> wrote:

Is Validity Just a Hypothetical or Conditional Characteristic?

No; there are also valid formulas - propositional forms that are true
in all states of affairs. The most famous two are Aristotle's axioms:
~(A & ~A) and (A v A). Most valid wff, though, are conditionals; ar

No, it is important to notice that the fact that an argument is valid
does not prove that the conclusion is true. Validity is a hypothetical
or conditional characteristic of _arguments_.

George is stating that the word "valid" also,
technically, applies to _propositional forms_ (or sentence forms) --
forms of propositions of which every instance is true. For example,
the sentence "Today is Monday, or it isn't" is necessarily true,
since it exhausts the alternatives. It is an instance of the form
"A or not-A", which is technically a valid form, but it is not
an argument -- there is no premise and no conclusion.

An argument may be one (compound) sentence, or composed of several
sentences. If it is a one-sentence argument (and so contains both
premises and conclusion), then, if it is a valid argument, not
only will the conclusion be true if the premise is (the hypothetical
or conditional characteristic), but the form of the sentence as a
whole will be a valid form, necessarily true in every instance
(the absolute characteristic). So the two definitions of "valid"
converge in this case.

George, in the above snippet, does not commit himself on whether an
actual proposition, as opposed to a propositional form, can also
enjoy the property of being valid.

1) George's post does not appear on my newserver, or at Google (???).

2) My usual newserver does not allow crossposting to more than
three boards. I assume that other subscribers may have
similar limits imposed -- you should bear that in mind
when cross-posting to many groups. It's kind of a pain
in the neck to reply.


it simply assures us that the conclusion
of the argument is true if the premises are and no valid formula makes
falshoods true, at least that I know of."No valid formula makes falsehoods true." --

Well, there's not
much that can make a falsehood true. I think you mis-typed here.
I guess you meant "... and no valid argument has true premises
and a false conclusion, at least that I know of." That is correct,
by the definition of "valid argument".

Is Validity Just a Hypothetical or Conditional Characteristic?

A deductive argument is said to be sound when the premises of the
argument are true and the argument is valid.

Saying that an argument is valid is
equivalent to saying that it is
logically impossible that the
premises of the argument are
true and the conclusion false.

A less precise but intuitively clear way of putting this is to say
that, in a valid argument, if the premises are true, then the
conclusion must be true.

Hi

Immortalist wrote:
Is Validity Just a Hypothetical or Conditional Characteristic?

A deductive argument is said to be sound when the premises of the
argument are true and the argument is valid.

Saying that an argument is valid is
equivalent to saying that it is
logically impossible that the
premises of the argument are
true and the conclusion false.

A less precise but intuitively clear way of putting this is to say
that, in a valid argument, if the premises are true, then the
conclusion must be true.

If you have a proof of the validity of
a sentence, you can look at the proof,
and will learn a lot of about the contribution
of the parts of the sentence to the validity
of the whole sentence.

Bye

Immortalist wrote:

On Jan 25, 8:37 pm, "George Dance" <georgedanc...@yahoo.ca> wrote:
On Jan 25, 12:53 pm, "Immortalist" <reanimater_2...@yahoo.com> wrote:

Is Validity Just a Hypothetical or Conditional Characteristic?

No; there are also valid formulas - propositional forms that are true
in all states of affairs. The most famous two are Aristotle's axioms:
~(A & ~A) and (A v A). Most valid wff, though, are conditionals; ar

No, it is important to notice that the fact that an argument is valid
does not prove that the conclusion is true. Validity is a hypothetical
or conditional characteristicof _arguments_.

George is stating that the word "valid" also,
technically, applies to _propositional forms_ (or sentence forms) --
forms of propositions of which every instance is true. For example,
the sentence "Today is Monday, or it isn't" is necessarily true,
since it exhausts the alternatives. It is an instance of the form
"A or not-A", which is technically a valid form, but it is not
an argument -- there is no premise and no conclusion.

An argument may be one (compound) sentence, or composed of several
sentences. If it is a one-sentence argument (and so contains both
premises and conclusion), then, if it is a valid argument, not
only will the conclusion be true if the premise is (the hypothetical
or conditional characteristic), but the form of the sentence as a
whole will be a valid form, necessarily true in every instance
(the absolute characteristic). So the two definitions of "valid"
converge in this case.

George, in the above snippet, does not commit himself on whether an
actual proposition, as opposed to a propositional form, can also
enjoy the property of being valid.

1) George's post does not appear on my newserver, or at Google (???).

2) My usual newserver does not allow crossposting to more than
three boards. I assume that other subscribers may have
similar limits imposed -- you should bear that in mind
when cross-posting to many groups. It's kind of a pain
in the neck to reply.

it simply assures us that the conclusion
of the argument is true if the premises are and no valid formula makes
falshoods true, at least that I know of."No valid formula makes falsehoods true." -- Well, there's not
much that can make a falsehood true. I think you mis-typed here.
I guess you meant "... and no valid argument has true premises
and a false conclusion, at least that I know of." That is correct,
by the definition of "valid argument".





If the premises are not true to begin with, then even a valid argument
cannot ensure that the conclusion is true. But only valid arguments are
truth-preserving.

A deductive argument is said to be sound when the premises of the
argument are true and the argument is valid.

Saying that an argument is valid is
equivalent to saying that it is
logically impossible that the
premises of the argument are
true and the conclusion false.

A less precise but intuitively clear way of putting this is to say
that, in a valid argument, if the premises are true, then the
conclusion must be true.

If the premises

1. If everything is caused,
then no one acts freely. and

2. Everything is caused.

are both true, then it must also be true that

3. No one acts freely.

As a simple matter of logic, it is impossible that premises (1) and (2)
should both be true and conclusion (3) be false. It is important to
notice that the fact that this argument is valid does not prove that
the conclusion is true. Validity is a hypothetical or conditional
characteristic; it assures us that the conclusion of the argument is
true if the premises are...

...If an argument can be valid and yet have a preposterously false
conclusion, what good is validity? Why should we be concerned with
validity at all? The answer is that a valid argument is
truth-preserving. Truth in the premises of a valid argument is
preserved in the conclusion. Of course, if the premises are not true to
begin with, then even a valid argument cannot ensure that the
conclusion is true. But only valid arguments are truth-preserving. An
analogy might help to clarify this point. Roughly;

Valid arguments preserve truth as
good freezers preserve food.

If the food you place in a freezer is spoiled to begin with, then even
a good freezer cannot preserve it. But if the food placed in a good
freezer is fresh, then the freezer will preserve it. Good freezers and
valid arguments preserve fresh food and truth, respectively. But, just
as the former cannot preserve food when the food is spoiled, so the
latter cannot preserve truth when the premises are false. Garbage in,
garbage out. Nevertheless, food freezers and valid arguments are worth
having because they do preserve something good when one has it, and
without them one may wind up with something rotten even when beginning
with something impeccable. Thus, validity is to be desired and
invalidity is to be eschewed.What you seem to be suggesting, here and above, is that only
sound inferences have value. This is not true. We may also
come to know the falsehood of statements by false conclusions
fairly drawn from them.

Philosophical Problems and Arguments: An Introduction
by James W. Cornman, Keith Lehrer, George Sotiros Pappashttp://www.amazon.com/exec/obidos/tg/detail/-/0872201244/http://hume...

The second URL in your original post didn't work.

In the propositional calculus, there are also valid formulas:
propositional forms that are true in all possible states of affairs.
The two most famous are Aristotle's axioms: ~(A & ~A) [Law of
Non-Contradiction] and (A v A) [Law of Excluded Middle. Most valid
wff, though, are conditionals.Not true. There are an infinite number of valid conditionals, and
an infinite number of valid non-conditionals.

For instance, the valid formula that
correspond to modus ponens is (P -> ((P -> Q) -> Q). What ties the two
notions of validity together is the Deduction Theorem, by which every
valid argument has a valid corresponding conditional.- Hide quoted text -- Show quoted text ---
hz

--
Posted via a free Usenet account fromhttp://www.teranews.com- Hide quoted text -- Show quoted text -

Immortalist wrote:
On Jan 25, 8:37 pm, "George Dance" <georgedanc...@yahoo.ca> wrote:
On Jan 25, 12:53 pm, "Immortalist" <reanimater_2...@yahoo.com> wrote:

Is Validity Just a Hypothetical or Conditional Characteristic?

No; there are also valid formulas - propositional forms that are true
in all states of affairs. The most famous two are Aristotle's axioms:
~(A & ~A) and (A v A). Most valid wff, though, are conditionals;


No, it is important to notice that the fact that an argument is valid
does not prove that the conclusion is true.


I think it's as important to notice that I did not say that the
conclusion of a valid argument is true; what I did say was that the
corresponding conditional of a valid argument is always true.

Validity is a hypothetical
or conditional characteristic; it simply assures us that the conclusion
of the argument is true if the premises are


- and that at least one premise is false if the conclusion is; don't
forget that -


and no valid formula makes
falshoods true, at least that I know of.



Are you saying that either of the valid formulas I quoted to you [~(A &
~A) and (A v A)], or any other valid formula FTM, could be false in
some cases? Can you give an example?

If the premises are not true to begin with, then even a valid argument
cannot ensure that the conclusion is true. But only valid arguments are
truth-preserving.


Philosophical Problems and Arguments: An Introduction
by James W. Cornman, Keith Lehrer, George Sotiros Pappashttp://www.amazon.com/exec/obidos/tg/detail/-/0872201244/http://hume....

In the propositional calculus, there are also valid formulas:

For instance, the valid formula that
correspond to modus ponens is (P -> ((P -> Q) -> Q). What ties the two
notions of validity together is the Deduction Theorem, by which every
valid argument has a valid corresponding conditional.

On Jan 26, 7:05 pm, "George Dance" <georgedanc...@yahoo.ca> wrote:





On Jan 26, 8:39 am, ZerkonX <ZER...@zerkonx.net> wrote:

On Thu, 25 Jan 2007 09:53:50 -0800, Immortalist wrote:
Valid arguments preserve truth as good freezers preserve food.I partially disagree with this.

There are two things you are talking about here. The first is the If/Then
process of logic. However this is separate from the content of the
argument so a false premise can be preserved by a correct argument.

So, let's say:
' 1. If everything is caused,..'

.... might have a different outcome if 'If everything is reaction,..'
started the ball rolling. Or 'If everything causes everything... etc

Same with 'If everything is made by (my own) God,..', as another example.

So the mechanics of process can preserve falsehoods also.

What is preserved that is 'truth' is the process itself but that's all.
Kinda like measuring the distance between two points does not validate
distance but rather the notched stick that is being used.
Not at all; 'falsehood preserving' can also give you information, but
in the opposite direction. Because it is also true of any valid
arguments that, if its conclusion is false, at least one of its
premises has to be false. That's an extremely useful, though often
overlooked, application of logical reasing.

Good point, also if we carve these words into wooden placks and put
them over the fireplace we can get a warm intellectual feeling too,
but whatd that got to do with soundness and validity.

I like Popper's
view on trial and error and progress, through falsifiability.

- Show quoted text -

On Jan 26, 7:04 pm, herbzet <herb...@gmail.com> wrote:


Immortalist wrote:

On Jan 25, 8:37 pm, "George Dance" <georgedanc...@yahoo.ca> wrote:
On Jan 25, 12:53 pm, "Immortalist" <reanimater_2...@yahoo.com> wrote:

Is Validity Just a Hypothetical or Conditional Characteristic?

No; there are also valid formulas - propositional forms that are true
in all states of affairs. The most famous two are Aristotle's axioms:
~(A & ~A) and (A v A). Most valid wff, though, are conditionals; ar

No, it is important to notice that the fact that an argument is valid
does not prove that the conclusion is true. Validity is a hypothetical
or conditional characteristicof _arguments_.

George is stating that the word "valid" also,
technically, applies to _propositional forms_ (or sentence forms) --
forms of propositions of which every instance is true. For example,
the sentence "Today is Monday, or it isn't" is necessarily true,
since it exhausts the alternatives. It is an instance of the form
"A or not-A", which is technically a valid form, but it is not
an argument -- there is no premise and no conclusion.

Validity is a hypothetical or conditional characteristic; it assures
us that the conclusion of the argument is true if the premises are
true. The concept your adding to "A or not-A" is hypothetical, not the
statement itself. The concept is the construction called
"contradiction vs consistency" which is a theory your proposing about
that proposition Av~A.

An argument may be one (compound) sentence, or composed of several
sentences. If it is a one-sentence argument (and so contains both
premises and conclusion), then, if it is a valid argument, not
only will the conclusion be true if the premise is (the hypothetical
or conditional characteristic), but the form of the sentence as a
whole will be a valid form, necessarily true in every instance
(the absolute characteristic). So the two definitions of "valid"
converge in this case.

But your forgetting "soundness" criteria since if the premise, however
stated, is not sound then the argument is false, in some instances.

We
might introduce the concept of necessity and contingency here;

A proposition is Logically Necessary, necessarily true or just plain
necessary if the statement could not possibly be false. If it is true
in all possible worlds. The concept depends therefore upon what we
consider to be a possible world. The narrower our conception of
possible world, the broader our conception of necessity.

A statement is necessarily false (or self contradictory) if it is
false in every possible world.

If a statement is true in some, but false in other possible worlds
then it is contingent. It is intended that all statements of a certain
class are either necessary or contingent.

http://www.rbjones.com/rbjpub/philos/logic/006.htm

In philosophy and logic, contingency is the status of facts that are
not logically necessary. See modal logic. Contingency is opposed to
necessity: a contingent act is an act which could have not been, an
act which is not necessary (could not have not been).

http://en.wikipedia.org/wiki/Contingency

I was proposing that in a valid argument, if the premises are true, then the
conclusion (must) be true.