From: scg@mentor.cc.purdue.edu (Kelly Martin)
Subject: Re: Criticism:  "There's no logic in Christianity"
Reply-To: scg@mentor.cc.purdue.edu
Organization: Gender Anarchists United
	<1992Dec21.162627.27379@csrd.uiuc.edu>
	<1992Dec24.050037.8184@microsoft.com>
Date: Thu, 31 Dec 1992 02:57:54 GMT

bobsarv@microsoft.com (Bob Sarver) writes:
>Correctly constructed arguments can be both false and illogical.

Arguments are not true or false; propositions are.  Deductive
arguments have two main properties, soundness (what you incorrectly
refer to as "truth"), and validity (what you call "logical").

All sounds arguments are valid; all invalid arguments are unsound.  An
argument can be valid but not sound.

Validity refers to form; soundness to content.  An argument is valid
(or not) regardless of the truth of any proposition it contains; the
soundness of an argument depends on both its validity and the truth of
all of its premises.

>This is an example which parallels yours closely:

>1.  Dragons exist and like to eat people
>2.  Silver has been blessed by the gods; that is why it shines so bright
>3.  Dragons hate the metal silver
>4.  SO:  it is good to wear silver

>The argument is false because the science doesn't back it up (dragons
>don't exist).

It is unsound because 1, 2, and 3 are not demonstrably empirically
true, and invalid because 4 does not deductively follow from 1, 2 and
3.  I refuse to use the term "false" to refer to an argument.  If you
added the additional premises that "it is good not to be eaten by
dragons" and "dragons will not eat anything wearing something they
hate", you would have a valid, but presumably unsound, argument.  In
the modified argument, proposition 2 plays no role.

>The argument is illogical because there is no demonstrated
>cause-and-effect between the steps.  Instead of a logical principle
>like [example of specification deleted] what we have instead is a
>growing list of unproven assumptions that must be simply accepted,
>without any logical formula to show *why* they must be accepted.
>That is why it is not logical.

Actually, a growing list of assumptions (read: premises) is the form
of all arguments.  Nearly every argument has at least one premise
which is simply asserted to be evidently true.  The only proposition
in any argument which is expected to have a "logical formula" behind
its truth is the conclusion, which is expected to follow from the
premises.  Most arguments contain intermediary conclusions, but these
are really sub-arguments used to produce additional premises which are
demonstrably true GIVEN THE PRIOR PREMISES.  Premises are ALWAYS
assumed true.

>Arguments which are composed soley of take-it-on-faith axioms are not
>logical arguments.

Nonsense.  This argument is both sound and valid:

1.  I am in my kitchen.
2.  My cat is in my bedroom.
3.  I am not in the same room as my cat.

You have to take, on faith, my word of the truth of 1 and 2.  The
conclusion (3) follows obviously from the premises, and the premises are
evidently empirically true.  The argument is valid, and sound.

And, of course, I am completely ignoring the topics of inductive
logic, modality, and possible worlds. :)

Kindly refrain from debating the philosophy of logic when you don't
even know the basic terminology.  I'd refer you to the text I used in
my Introduction to Philosophy class, but I can't find it right now. :(

Regards, 

Kelly
--
Standardized tests measure the ability to take standardized tests.
	-- elg@usl.edu (Eric Lee Green), misc.education