RE: Logic Again (was Changing One's Mind)

From: Lee Corbin (lcorbin@tsoft.com)
Date: Sat Jun 15 2002 - 22:58:30 MDT


Louis writes

> From: "Lee Corbin" <lcorbin@tsoft.com>
>
> > The confusion arises over a difference between
> > the application of *formal logic* and everyday
> > (or Aristotelian, as you remind us) logic.
>
> I am reminding you that "formal logic" was invented by Aristotle. You keep
> trying to label my logic (and now Aristotle's logic) as not "formal logic".

Oh, dear. Sorry if I've got that a bit messed up from normal
usage. Let me discourse a bit about what I think logic is,
both formal and informal logic. And also about how we often
misuse the term in daily life---although if such "misuse" is
so common as I think it is, then, well, whose to say that the
way all the people use it is wrong and I'm right?

Here is a nice example of described logic: the logic of
chess is that if piece A is guarding piece B, then if you
attack piece A, you win piece B. The statement is not
complete or conclusive as it stands, of course, but it
does distinguish nicely between real life in chess. (The
key difference is that only one move at a time happens in
chess, and that's where this logic comes from.)

Are children doing formal logic, or just plain informal
logic, when they deduce that the coin is in the car from
the premises that the coin is in the bunny and the bunny
is in the car? I say that they're being logical all right,
but that they're hardly using formal logic.

(I have often been accused by friends and acquaintances of
being very logical. What they really meant was that I
take some principle or insight and apply it further than
other people that they know. Our daily use of "logical",
"illogical", etc., has little to do with the patterns
Aristotle discerned.

To me, formal logic is literally "form-al" logic, in the
sense that the particulars have been stripped away and
all that is left are the patterns. My "chess logic"
above is an example. Try asking a four year old "if all
A are B, and all B are C, then is it true or false that
all A are C", and you'll just get a blank stare: the
four year old hasn't seen the pattern enough to abstract
from it.

Since Aristotle indeed abstracted away, I'm wrong and you're
right: Aristotle's logic is formal logic. But here is
what I was trying to say:

In daily life, people use the syllogism pattern exceedingly
often, but without abstracting it to the level of formal
logic. In this case, I claim that they're not using
Aristotle's formal logic at all; they're using logic
informally, exactly the way a four year old does.

Cutting to the chase, I further submit that people very,
very rarely make logical errors of the type that could
be reduced to, or explained by, a misapplication of
formal logic. You're almost always wrong when you
believe that you've spotted some articulate person
committing a logical fallacy.

Lee



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