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Re: [ontolog-forum] Imagery in Scientific Thought

To: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "John F. Sowa" <sowa@xxxxxxxxxxx>
Date: Sat, 15 Dec 2007 23:14:47 -0500
Message-id: <4764A637.4080007@xxxxxxxxxxx>
Kathy,    (01)

I just wanted to make it clear that logic, by itself, cannot derive
a contradiction from any collection of positive observation statements,
no matter how absurd they may sound.    (02)

 > The statement "The bar has length 7.1 cm AND the bar has length
 > 6.8 cm" is a contradiction.    (03)

By themselves, the two statements are not contradictory, but
a contradiction arises as soon as you add an axiom about length:    (04)

     No object can have two different lengths at the same time.    (05)

This is a principle of ontology, which introduces a negation.
In conjunction the two positive statements, the negative
statement can generate a contradiction.    (06)

I agree that the following statement can be true, even in conjunction
with the above ontology:    (07)

 > The statement "Sensor A observed the bar to have length 7.1 cm
 > AND Sensor B observed the bar to have length 6.8 cm" is not
 > contradictory.    (08)

I certainly agree with the following point, which is true, even
with all the normal assumptions about ontology, science, etc:    (09)

 > It is essential that observations be identified as observations
 > and not as statements about the entities being observed.  It is also
 > essential to say something about who or what is doing the observing
 > and about the conditions under which the observation occurs (e.g.,
 > accuracy of sensors A and B under various lighting conditions;
 > lighting conditions at time of observation; etc.).  Of course, this
 > information may be unavailable.  In this case, it is all too common
 > to say nothing about potential observational error, and for the
 > consumer to simply assume the observation is perfectly accurate.
 > This often generates contradictions.    (010)

John    (011)

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