Logical Thinking LO21591

Winfried Dressler (winfried.dressler@voith.de)
Wed, 12 May 1999 14:13:07 +0100

Replying to LO21558 --

Was: "Junk" Science

I very much enjoy this thread. It helps to get the square wheeled waggon
out of the mud (using a metaphor by Scott Simmermann).

At de Lange quoted John Gunkler:

>>1. Fallacy of the Consequent (type 1 -- Denial of the antecedent):
>>
>>If p is true then q is true. p is not true. Therefore, q is not true.
>>
>>["If I go to the mall I always buy a toy. I did not go to the mall.
>>Therefore, I did not buy a toy." -- This is false, however, because
>>I may have bought a toy at the corner drug store.]
>>
>>Note: The example above is often abbreviated as follows ...
>>If p then q. Not p. Therefore not q. [This is taken to mean the
>>same thing as the longer version above.]

I don't know which part of At's explanations to quote in order to make my
point, so I can only acknowledge that it appeared to me while reading At's
mail - and to try on my own.

John, are you sure whether the statement

The conclusion "If p is true then q is true. p is not true. Therefore, q
is not true." is a fallacy

is true? It also may be false, making it a fallacy itself.

In your example it became a fallacy because of the additional information
"I may have bought a toy at the corner drug store." Another information
would have made the conclusion valid: "The mall is the only place where
toys can be bought." Of course we know which of the two contradictory
pieces of information is true, but this is part of your example, which is
designed to show a fallacy, not a valid conclusion (you got what you put
into it - isn't this also a common fallacy? What is it named?).

Let me give another (more LO related) example:

p: we practice the five disciplines (including team learning) of Peter Senge
q: we are a learning organization

What does become of your fallacy?

If we really practice the five disciplines (including team learning) of
Peter Senge then we are a learning organization. We do not practice team
learning. Therefore, we are not a learning organization.

What additional information do we need to decide, whether we are facing a
fallacy or not? We need to know the answer to the question: "Is team
learning a NECESSARY condition for a learning organization?" If you answer
this question with "Yes", there is no fallacy above. If someone else
answer this question with "No", s/he may become angry with you because you
made such a fallacious conclusion.

Also already the first conclusion may be a fallacy: If p then q. In this
case, we need to check, whether p is SUFFICIENT for q to exist. Is going
to the mall really sufficient to buy a toy? I may have forgotten my money.
Or the toys may have run out. In my example, this is equivalent to the
question whether the five disciplines are sufficient for a learning
organization to emerge.

So what is more constructive: A dispute on fallacies, or the search for
those questions needed to expose hidden assumptions and have a dialogue on
them?

We are facing two extreme attitudes towards fallacies:

The expert attitude: "What a nonsense! I know logic and I can tell you:
What you are saying is nonsense. What a fate to be surrounded by such
ignorants like you!" Hidden assumptions? "There are no hidden assumptions.
Look, we, the community of experts, are in a process to make everything
explicit by defining all used terms and establishing the relevant
connections by means of scientific research!"

The teacher/learner attitude: "Sorry, I cannot follow your conclusions. I
am sure that you are trying to express something that is sensible for you.
So let us examine, what assumptions you made, let's check whether we can
agree on them and include them into your reasoning, so that we get the
full picture, to which we both agree that it's common sense."

We have a saying or metaphor stating, that hens which grew up at the North
Sea where a constant wind is blowing, would fall if the wind suddenly
stops blowing. What will happen to humans, who have been exposed to
logical thinking only by the expert mode (parents, school teachers,
superiors), when they meet a person with the attitude of a teacher? How
long will it take for their own logic to open up and come out, giving it a
real chance to correct or improve? And if they opened, how easy will it be
to intimidate or hurt them, so that they will shut the door for ever?

Liebe Gruesse,

Winfried Dressler

-- 

"Winfried Dressler" <winfried.dressler@voith.de>

Learning-org -- Hosted by Rick Karash <rkarash@karash.com> Public Dialog on Learning Organizations -- <http://www.learning-org.com>