From: bill@ut-emx.uucp (Bill Jefferys)
Newsgroups: talk.origins
Subject: Re: A question Bob has never answered.
Date: 7 Aug 91 18:46:38 GMT
Organization: The University of Texas at Austin; Austin, Texas

...and while we're at it, just before he disappeared
the last time (in February) Bob posted the following:

#From: bobb@tekfdi.FDI.TEK.COM (Robert Bales)
#Newsgroups: talk.origins
#Subject: Ages of ice layers
#Message-ID: <5241@tekfdi.FDI.TEK.COM>
#Date: 18 Feb 91 01:30:39 GMT
#Organization: Tektronix Inc., Beaverton, Or.

[much deleted]

#To return to the subject with which I started this letter, I am working on a
#response to Greg's latest post on short-period comets.  I should be able to
#finish it during the week.  I also had hoped to do a lengthy response to
#Bill Jeffy's latest post on isochons:  it is, in my opinion (for whatever
#that's worth :-) :-)) the best all-in-one-place summary of the evidence for
#radioactive dating accuracy I've seen in a while.
#
#   Bob Bales
#   Tektronix, Inc.

As far as I know, Bob never did respond to my post.
For his reference, here it is again, followed by
a short clarification from Chris Stassen. Maybe this
time Bob will honor us with a response.

Bill Jefferys

---

#From postnews Sat Feb 16 09:14:37 1991
#Subject: Re: Continuation of dating accurracy discussion
#Newsgroups: talk.origins
#References: <5215@tekfdi.FDI.TEK.COM>

I will respond only to Bales' most important points. Peter Lamb 
has already dealt adequately with much of Bales' article, and to 
save net bandwidth I will not duplicate his effort.

In article <5215@tekfdi.FDI.TEK.COM> bobb@tekfdi.FDI.TEK.COM 
(Robert Bales) writes:

#I ask those who disagree with me to read very carefully what I am saying, to
#see if we can make  some progress.
#
#In article <42804@ut-emx.uucp> bill@ut-emx.uucp (Bill Jefferys) writes:
#
#># me
#
#[regarding isochron dating]
#
#>#I am not aware that they are irrelevant, precisely because they ARE
#>#relevant. When you make a measurement based on isotopic ratios, you are
#>#getting a measurement of ALL factors which affect the ratios.  It is
#>#incorrect to state this to be a measurement of just *one* of the factors.
#
#>I'm sorry, Bob, but this is simply untrue.
#
#The above statement does not say what the age of the earth is. It is simply
#a statement that if you ignore some of the factors that can influence a
#result, the conclusions you draw from that result are likely to be wrong.
#I maintain that this logical principle is true.

I read what you wrote very carefully. I intended (perhaps 
unclearly) to dispute your claim that Durrance's 11 points are 
relevant to isochron dates. They are not, despite the following 
attempt of yours to revive Durrance:

#Most, but not all, of the points from Durrance are specifically about
#Potassium-Argon dating.  Since isochrons do not use this method, the specific
#points do not apply. However, before listing specifics, Durrance makes a
#general statement:
#
#    "Thirdly, to obtain the age of formation of a rock or mineral, the
#    material must have remained a close chemical system since its
#    formation, with neither gain nor loss of radioactive parent or
#    daughter atoms. . . . Unfortunately, geologic materials and
#    environments do not often meet this requirement." (_Radioactivity
#    in Geology: Principles and Applications_, by Eric Durrance of the
#    University of Exeter.)
#
#Since isochron methods deal with geologic materials and environments, they
#fall within the scope of what Durrance talks about.

They do not. Dalrymple flatly contradicts you. He writes:

   Note that the Rb-Sr isochron method requires no knowledge or 
   assumptions about either the isotopic composition or the 
   amount of the initial daughter--in fact, that is something 
   learned from the method. The rocks or minerals must have 
   remained closed systems to rubidium and strontium since 
   formation, BUT IF THIS CONDITION IS NOT TRUE, THEN THE DATA 
   WILL NOT PLOT ON AN ISOCHRON. Also, if either the initial 
   isotopic composition of strontium is not uniform or the 
   samples analyzed are not cogenetic, then the points will not 
   fall on a straight line. As the reader can easily see, the 
   Rb-Sr isochron method is elegantly self-checking. IF THE 
   REQUIREMENTS OF THE METHOD HAVE BEEN VIOLATED, THE DATA 
   CLEARLY SHOW IT. [Emphasis mine.]

In other words, when using the isochron method, you will KNOW if 
the system has not remained closed. Such rocks are not used in 
isochron dating. They CANNOT be used for proper isochron dating, 
because for rocks with such histories the data do not plot on an 
isochron. Therefore, Durrance's comments do not apply to properly 
determined isochron dates. Nor did Durrance intend his comment to 
apply to isochron dating, since he was only discussing gas-
retention ages, specifically K-Ar ages. You should give up this 
line of argument, Bales. It is not truthful. It is a flagrant 
misuse of Durrance's words.

#For instance, the statement is often made (as by Bill below)
#that isochron methods determine the initial isotope ratios in the rock.
#For this to be a scientific rebuttal of what I say would require data
#showing what the known initial isotope ratios of rock samples were and
#what the isochon method found them to be.  I have not seen any such data for
#rocks said to be billions of years old.

You are dead wrong. This statement proves that you do not 
understand science (a fact that you have made abundantly clear to 
us over the years). Obviously, science cannot PROVE that any rock 
is billions of years old, since no one was there to see it formed. 
But that isn't what science is all about, anyway. Science is about 
DATA and FALSIFIABLE THEORIES. If you have DATA, you are required 
to come up with specific THEORIES and see if the data agree with 
the theories. If you think a theory is wrong, you have to come up 
with a BETTER THEORY. If you don't do this, then you aren't doing 
science. Just saying that you don't believe the theory isn't 
science.

Here are our DATA: We have literally tens of thousands of rocks 
containing straight-line isochrons. We have young rocks with 
horizontal isochrons. In many instances we have isochrons 
belonging to different decay systems, and in such cases we 
invariably find that they give the same dates. Very significantly, we
have NO examples of rocks with negatively sloped isochrons. We have 
numerous instances where rocks from many different parts of the 
world are found associated with a given stratum of the geologic 
column, and invariably we find that they give the same isochron 
dates, and that the dates are in the same order as inferred from 
the order of rocks in the geologic column. We also have a number 
of examples where we can associate rocks with ages determined by 
other means. For example, the speed of tectonic plates can be 
determined directly by lunar laser ranging. Radiometric ages of 
rocks from the Hawaiian Islands agree with the ages inferred for 
them from the motion of the tectonic plate on which they are 
located.

The SIMPLEST THEORY that predicts (and therefore explains) all 
these DATA (simple in the sense of Occam's razor) is that physics 
is correct, and the radiometric dates are real dates. This is 
simple because it is consistent with well-established physics. It 
explains why straight-line isochrons exist, it explains why the 
slope of isochrons appears to increase with age as inferred from 
independent methods, it explains why there are no negative-slope 
isochrons, and it is the only explanation that I am aware of that 
explains why straight-line isochrons even exist at all!

There can be only one SCIENTIFIC counter to this argument. You 
must come up with a comprehensive THEORY that explains all of 
these data MORE SIMPLY than the one I have given. I CHALLENGE you 
to do so. To count, you must describe your theory IN DETAIL. Your 
theory must (1) EXPLAIN why isochrons exist, and in such 
abundance; (2) EXPLAIN why the slopes of the isochrons are 
correlated so strongly with different strata in the geologic 
column, in the exact same order as found by the Creationist 
scientists who first established it; (3) EXPLAIN why the slopes 
are correlated with tectonic plate movements, in precise agreement 
with the amount that is observed by independent methods such as 
lunar laser ranging; (3) EXPLAIN why negatively-sloped isochrons 
are NEVER observed; (4) EXPLAIN why isochrons of different decay 
systems in the same rocks invariably give the same ages; and so 
on, throughout the enourmous range of observed data on radiometric 
ages. Your theory must be consistent with known physics (or if 
not, it must be backed up with data that shows that physics is, 
indeed, wrong). Furthermore, your theory must be FALSIFIABLE by 
data. Your handwaving, your "well, you haven't PROVED that 
isochrons give real dates" are not scientific arguments 
(excepting, perhaps, to yourself and others of your ilk who don't 
understand what science is about).

#When radioactive dating is first introduced, it is often stated to be
#reliable because of the stability of radioactive decay. The examples of
#radioactive dating errors show that this characteristic is *not sufficient*
#to insure accuracy.  Experimental data on the accuracy of radioactive dating
#is, obviously, relevant to radioactive dating.  Since the isochron method is
#a radioactive dating method, the data is relevant.

The evidence you have given on the accuracy of K-Ar dating is not 
relevant to isochron dating. The problems of K-Ar dating do NOT 
apply to isochron dating because the two methods use entirely 
different principles. The fact that both involve radioactive decay 
is a superficial and irrelevant detail.

#Bill and others talk about theory and generalities.  But sorry. I have
#presented multiple cases in which the assumptions have been applied to
#specific samples and they have yielded dates, at least in one case with
#no indication anything was wrong.  Yet those dates (in these cases) are
#known to be wrong.  Direct experimental indication that assumptions are
#wrong IS a reason to doubt them.

You have never, to my knowledge, supplied a single example of a 
correct application of the ISOCHRON method that has yielded 
incorrect dates for straight-line isochrons (see Dalrymple's 
comment above). If I am wrong, please supply a CITATION to the 
refereed literature.

Note to Bob: "Science" is NOT a citation. "Science, v. 167, pp. 
466-468 (1970)" is a citation.

#>which are consequences of basic, well-understood, and 
#>well-tested physics and chemistry.

#Except that the tests show that the assumptions can be wrong.

What tests? Please provide a CITATION to the refereed literature 
that shows that the assumptions involved in isochron dating can be 
wrong when the conditions mentioned by Dalrymple are satisfied.

#>Furthermore, contrary to what you say, isochron methods are indeed 
#>validated by completely independent methods having nothing to do 
#>with radiochronometry. For example, the order of ages established 
#>by this method agrees with the sequence of rocks in the geologic 
#>column. . . .
#
#Isochron methods have been used to assign ages of billions of years to rocks.
#Since the sequence of rocks in the geologic column does not assign absolute
#ages, it is logically incapable of validating isochron dates.  Although it
#is consistent with isochron dates, it is equally as consistent with many
#other theories.

What other theories? Be specific. You have claimed that "other 
theories" exist. Please describe these alleged "other theories" in 
detail. Explain exactly how these "other theories" predict the 
DATA I mentioned in my challenge.

Bill Jefferys

-----


#From ut-emx!cs.utexas.edu!wuarchive!uunet!shelby!agate!bionet!alc!stassen Tue Feb #19 15:05:39 CST 1991
#Article: 14133 of talk.origins
#Path: ut-emx!cs.utexas.edu!wuarchive!uunet!shelby!agate!bionet!alc!stassen
#From: stassen@alc.com (Chris Stassen)
#Newsgroups: talk.origins
#Subject: Re: Isochron Technique Info Requested (Corrections)
#Message-ID: <756@cortez.alc.com>
#Date: 19 Feb 91 17:37:32 GMT
#References: <1991Feb18.102621.1@si194b.llnl.gov> <748@cortez.alc.com>
#Organization: The Lion's Den, San Jose
#Lines: 64

[First part of article deleted]

[Regarding Matt's fourth question]
>> 4) What does the slope tell you and why no negative slopes expected?

I hadn't seen Bill Jefferys' posting when I made the reply.  I think
I can give a better answer in the context of what I think Bill was
trying to say to Bob Bales.
	In trying to explain how isochron plots could be meaningless,
Bob previously claimed that randomly scattered points "could be anywhere,
including on a line."  This is what (I believe) prompted Bill to comment
on lack of negative slopes.
	I think Bill was saying that randomly-generated lines from
randomly scattered points should have negative slopes half of the time.
However, the 'natural' (known) processes of mineral formation and
radioactive decay are not capable of producing negative slopes.

All isochrons which pass contamination checks give positive slopes.
Therefore, the "random scattering producing a line" hypothesis is
demonstrably inferior, because it doesn't account for the lack of
negative slopes.  (Is that right, Bill?) [Yes, that is right--whj]
-- 
Chris Stassen				[fernwood.mpk.ca.us!]alc.com!stassen


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-- 
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