[SystemSafety] A Whimsical Paradox

[Michael Jackson]

Peter:

Your logical paradox paper is fun. Thank you.

I think we must distinguish two classes of case in which everyday reasoning
does not 'adhere to classical logic'. One is the case of a person who says
"Eight times seven equals fifty four". The other is the case of the person who
says "Everybody loves my baby but my baby loves only me."

The first person intends to make a true assertion about arithmetic, but by
ignorance or carelessness, or incompetence at calculation, instead asserts
a falsehood. The second person makes a statement apparently implying "I
am my baby" (work it out!), but intends no such implication and, of course,
does not believe it and would certainly deny it.

The second case merely reflects the looseness of everyday language. Even
a seemingly precise statement ("Everybody loves my baby") may use a term
('everybody') informally and loosely: the speaker means, and the hearer will
understand, that in this assertion 'everybody' does not include 'my baby'.

When we include terms denoting phenomena of the real world we must rely
on very loose interpretations. Perhaps "P1 loves P2" must be understood to
be irreflexive: P1 /= P2 is implied because for P1 = P2 we would introduce
the word 'self' somewhere. Similarly, with suitable interpretations, 
the matter
of 'confidentiality' need involve no logical inconsistency.

However hard we try to tighten our interpretations there is always room for
further doubts. The interesting question is: How can we ever model the real
world phenomena adequately for dependable system development? The key,
I think, is to recognise that a model, with its interpretations and 
universally
quantified assertions, can be good enough in a particular restricted region of
the system's operating envelope. This ought to be (actually is?) an explicit
consideration in designing the structure of the system behaviour. Many real-
world models are needed for adequacy in the current region of the operating
envelope.

-- Michael Jackson





At 05:46 29/01/2015, Peter Bernard Ladkin wrote:
>I'd not really heard about the "Chem Trails" nonsense except 
>superficially, had an odd encounter on
>a bus, and asked people about it on a closed mailing list I am on. 
>Mike Holloway said, well,
>everyone believes *some* nonsense.
>
>I am interested in everyday reasoning, which, contrary to what many 
>people believe, regularly and
>justifiably does not always adhere to "classical" logic. I would say 
>that an example is Mike's
>claim. I saw the chance to construct a classical-logical paradox. 
>Maybe I did; maybe I didn't.
>
>The paper is aimed at curious teenagers rather than those with any 
>technical training. But at least
>one adult has claimed to find it interesting. Perhaps others here might?
>http://www.rvs.uni-bielefeld.de/publications/Papers/LogicalParadox20150126.pdf
>
>PBL
>
>Prof. Peter Bernard Ladkin, Faculty of Technology, University of 
>Bielefeld, 33594 Bielefeld, Germany
>Je suis Charlie
>Tel+msg +49 (0)521 880 7319  www.rvs.uni-bielefeld.de
>
>
>
>
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