> From: Lee Corbin [mailto:[EMAIL PROTECTED]
> Sent: Wednesday, August 17, 2005 12:48 AM
> John writes
> > Lee and Stephen:
> > since we have only our subjective access to "out
> > there" does it make any difference if it is "REALLY?"
> > like we interpret it, or in an untraceable manner:
> > different?

Colin the Control System (Instrumentation) Engineer says.....

It's the old repeatability and accuracy issue again. Subjective experience can 
be considered to be a very elaborate measurement. People not involved in 
real-world measurement continually get mixed up as they don’t understand the 
difference between accuracy and repeatability.

Extent to which a measurement matches and international standard.

Extent to which a measurement matches its own prior measurement.

For example the SICK DME 200 laser distance measurement instrument has an 
accuracy of about 10mm over 150m but a repeatability of 0.7mm

Why does this matter?

Because _within_ the measurement system is simply does not matter what the 
accuracy is! As long as systematic errors are repeatable, the systems behaviour 
will be repeatable. For example if the above instrument was in a warehousing 
system you are NOT interested in whether the crane gets to exactly 150.3 
meters! You are interested in it getting to what it THINKS is 150.3 meters so 
that it won’t crash into the shelving! Systematic errors are quite ok _within_ 
a system.

So, for subjective experience: Yes it can be an illusion, but a systematically 
erroneous, relentlessly repeatable illusion driven by measurement of the 
natural world where its errors are not important - .ie. not mission fatal to 
the observer. Experiential qualities, in their solipsistic presentation, need 
only be repeatable (my red/attached to the linguitic token RED), not 'accurate' 
(internationally standardized RED #12398765).

This is equivalent to saying that the experience of HOT and the actual hotness 
of reality (wobbly atoms) _do not have to be intimately/directly related_!!! 
They can be completely different and as long as the experience is consistently 
used the behaviour of the experiencer will be the same "OUCH".

Haven't we all asked 'is my red the same as your read'? Haven't we all 
concluded that we'd never be able to ascertain the difference because it really 
does not matter?...we all point to the object and agree its red.... 
repeatability.... meanwhile the actual physical reality of 'redness' is simply 
irrelevant and may not represent any real quality of the observed system at 

I really wish mathematicians and philosophers and theoreticians would get out 
and get dirty in the real world some times..... half of the damned wordfest 
would disappear immediately.

Grumpy today.... sorry.


Colin Hales

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