From: bobb@tekig1.PEN.TEK.COM (Robert W Bales)
Newsgroups: talk.origins
Subject: Re: In case Bales has convinced you of his honesty
Date: 17 Dec 92 20:48:26 GMT


Michael Siemon writes:

>Bales has in the past advertized in his .signature that he helps Tektronix
>make its instruments.  Now, the point he has NEVER addressed in ANY way,
>whatsoever, is the mutual confirmation of independent measurements of the
>same thing.

If I can avoid it, I don't want to get into a second discussion of posting
quotes to prove what I've said.  But we did discuss this for a while, probably
several years ago. Like Michael, some people noted my Tektronix affiliation
and listed how readings from measuring instruments would have to be treated
in order to be consistent with what I advocate for isochron data.  My response
was that this is the way I, Tektronix, and the rest of world treats instru-
ment readings. I am still waiting to hear why isochrom methods should be
treated differently.

>He *has* attempted to insist (rather beyond reason, actually) on potential
>"processes" of error in one or another method of dating.

I claim that results from methods which have been experimentally verified to
have error should be treated as if they might be in error.  Only those who
insist on an old earth appear to call this beyond reason.  In most areas, it
is non-contraversial standard procedure.

>That is all very well, but irrelevant.

The data I use gives experimental results on dating accuracy.  When consider-
ing the accuracy of dating methods, this is the MOST relevant information we
could have.  Experimental measurements take precedence over theory.

>It is *because* one wishes to control potential error in one method that one
>checks it against another.

Not really.  To control error in measurement, *standards* are used.  In times
past, for example, the length standard was a bar maintained by a government
under controlled conditions.  Now I believe it is a certain number of wave-
lengths of a particular light source.  The voltage standard is undoubtedly an
electric cell made up of particular matarials.  Since a standard defines a
quantity, it has no error.  In the US, standards are controlled by the NTIS,
formerly the NBS (National Bureau of Standards). Assume a measuring device
"A" measures the standard correctly.  Now if device "B" agrees with "A", it is
not said than both are accurate because they agree.  Rather, "A" is accurate
independent of "B" and because of this, "B" is accurate.  This process can
be continued, establishing a chain of "tracability" from any particular
instrument back to a standard.  Especially for important work, a measuring
device is considered accurate *if and only if* it is tracable.

If you to one of our manufacturing lines at Tektronix  and asked why we
believe an instrument we use for final checks, you would *not* be given a list
of all the other instrumentation it agrees with.  Instead, you
would be shown its calibration sticker, then taken to the cal lab and shown
records of how it was calibrated in a tracable manner.

>All technical work will regard the mutual consistency of (potentially each
>individually wrong) methods as validation of coherence and accuracy, and
>confirmation of the validty of the results of each one separately.

No. The results of a measurement technique or instrument are validated by
showing that the technique or instrument gives the correct result when measur-
ing a known standard value.  What result any other technique or method gives
reads is irrelevant in determing the accuracy of the one in question.

>If he is missing the point, or unable to comprehend the objection that
>is urged against him,

The point is, it is alleged, that since multple, at least somewhat independ-
ent measurements (I say "somewhat" because all use radiometric isochron
techniques) give the sme result, those measurements can be taken to be
accurate. I have never missed or been unable to comprehend this idea, which,
boiled down, says that this type of consistancy implies accuracy.  However, I
disagree with the validity of the principle for a very simple reason: it is
nowhere (else) accepted nor used in scientific or technical work.  Those
who claim that isochron measurements are accurate and who deny alternative
possibilities are basically saying that these measurements are a special
case exempt from normal measurement requirements.  Since they have not
justified this special case, I say the argument shouls be rejected.

>it is tantamount to an admission of technical illiteracy and incompetency
>for the job he holds.

To call the use of commonally accepted methods "illiteracy" or "incompetance"
indicates, IMHO,  either a lack of familiarity with how measurements are made
and/or a complete misunderstanding of what my position is.

   Bob Bales
   Tektronix, Inc.

I help Tektronix make their instruments. They don't help me make my opinions.