From: skinner@sp94.csrd.uiuc.edu (Gregg Skinner)
Subject: Re: Criticism: "There's no logic in Christianity"
Reply-To: g-skinner@uiuc.edu
Organization: UIUC Center for Supercomputing Research and Development
Date: Thu, 7 Jan 93 19:24:58 GMT

Mr. Sandvik makes clear his non-standard definition of "valid logical
argument":

>However, when we suddenly use many of the other logical a priori
>definitions to produce the end result, we need an agreement on the
>premises.

>My personal interpretation of a logically valid argument is one where
>the outcome is clearly a known statement.

What you need to accept is that your personal interpretation has
nothing to do with the usual definition of logically valid argument.
When you say, "There's nothing logical about Christianity", the
statement has meaning only to you.  It's like saying, "Kent Sandvik is
a toad," and when pushed to back up the statement saying, "My
interpretation of `toad' is someone who does not accept the usual
definition of valid argument."  It is hardly argumentum ad antiquitam
to request that we use terms according to their usual meaning,
especially those with precise meaning.

Further, you should realize your definition of logic indicts not only
Christianity, but any system in which the underlying assumptions are
not universally agreed upon.  Take for example psychology. There is
fundamental disagreement between the behaviorist and Freudian schools
of thought.  Is psychology therefore absent of logic?

Your disagreement about the assumptions that make up logic itself,
coupled with your need for agreement in order to find logic, leads to
the nonsensical conclusion: Logic is without logic.

>According to your definition of logical constructs you could indeed
>have valid conclusions from such un-asserted premises.

No.  I stick to the standard definition of valid logical argument.  It
has a premise and a conclusion which must be true if the premise is
true.  Propositions that are not in the premise and do not follow from
the premise cannot be used to reach a conclusion, for then the truth
of the premise would not then necessitate the truth of the conclusion.

>But it shows that if there are multiple outcomes, where's the logic???
>If we have multiple conclusions, maybe we have a problem somewhere,
>let's see, maybe in the assertions about premises?

What a ridiculous notion!  Certainly a set of premises can lead to
multiple conclusions.  Consider these true premises: January is a
month.  January has 31 days.  In the U.S. Martin Luther King Day is
celebrated in January.  In the U.S. New Year's Day is celebrated in
the same month as MLK Day.  From these we can validly draw at least
two conclusions: (1) In the U.S. MLK Day is celebrated in a month with
31 days.  (2) In the U.S. New Year's Day is celebrated in January.
There is no problem here: The premises are true, the conclusions
("outcomes") multiple, the logic is valid.

>Please, doesn't this show already the futility to make logical
>conclusions from premises we can't even agree upon? 

Hardly.  Consider an example.  A group of people could take a
particular set of premises that appeals to one of them, but not to the
others (i.e. there is disagreement).  The truth values of the premises
are not known.  The group could work out some of the logical
conclusions, then test them in some way against reality.  Would this
be useful?

Of course.  This is just a simple statement of the scientific method.
The set of premises is a scientific hypothesis.  The conclusions are
predictions.  The tests are experiments.

---

As it is apparent that not only is Mr. Sandvik babbling about things
he does not understand, but lying as well (e.g. about his
qualifications as a logician) I shall likely discontinue my
participation in discussions with him.  He has cited Russell as a
source for some of his ramblings, so I will report back briefly after
I determine how Russell defines "valid logical argument".  I doubt
severely what Russell has to say will differ from the standard
definitions, for his _Principa_Mathematica_ is considered the
outstanding modern work on logic.

Mr. Sandvik will, of course, continue his tirades about (his
misperceptions of) logic, and he may continue to lie from time to time
as well.  I suspect he will soon lack an audience for his nonsense.



                                   Gregg Skinner


	     From what has just been said about validity, it is clear
	     that the mere validity of an argument does not insure
	     the truth of its conclusion....

	     D.B. Terrell
	     "Logic: A Modern Introduction to Deductive Reasoning"








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