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Consistency of radiometric dating comes from selective reporting (Talk.Origins)

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Response Article
This article (Consistency of radiometric dating comes from selective reporting (Talk.Origins)) is a response to a rebuttal of a creationist claim published by Talk.Origins Archive under the title Index to Creationist Claims.


Claim CD020:

The use of radiometric dating in geology involves a very selective acceptance of data. Most discrepant dates are not published. This selective reporting may account for consistencies in the data; internal consistencies, mineral-pair concordances, and agreements between differing dating methods may be illusory.

Source:

  • Woodmorappe, John, 1979. Radiometric geochronology reappraised. Creation Research Society Quarterly 16(2): 102-129.
  • Woodmorappe, John. 1999. The Mythology of Modern Dating Methods. El Cajon, CA: ICR.


CreationWiki Response: (Talk.Origins quotes in blue)

1. Geologists cannot be selective about choosing results because measurements typically cost hundreds of dollars per sample. To date multiple samples and choose a concordant set from among them would require throwing out about $100,000 worth of data if dating methods gave chance results (Henke n.d.).

Talk Origins is over-simplifying the situation. Woodmorappe is not saying that concordance is entirely the result of chance, but that there are factors that reduce the randomness somewhat. He annualizes them as totally random to show that chance concordance is quite probable but does not claim that they are totally random. It also needs to be noted that the theoretical system behind radiometric dating explains any dating inaccuracies in terms of such things as leaching and contamination.

Furthermore, it is not just a simple question of geologists' being selective, but at least a 4 level filtering mechanism, with different people who have different motives and priorities.

  • At the top of the list are peer-review journals. They are the main means of publishing scientific data and they have non-scientific considerations such as keeping subscriptions, the journals' reputations, and the limitations of printing space. Journals like Nature publish at best 10% of submissions, and often rejections are made based only on space. They are not likely to waste space on data that is considered meaningless, and routinely doing so could harm both the journals' reputations and their subscriptions.
  • Geologists want their papers published and they would not be likely to include data that is considered meaningless, and therefore likely to prevent publication.
  • Dating laboratories have reputations to maintain, and if most of the results they produce are considered meaningless they would lose business and money. This would motivate them only to release such results to geologists when there was no alternative, and then only labeled as a contaminated sample.
  • The scientists working in the dating laboratories want to keep their jobs. If they keep producing worthless results, they may lose their jobs. This would motivate them to keep trying to find an acceptable result.

This is not to imply dishonesty; it is just that the theoretical system behind radiometric dating explains any dating inaccuracy. Everyone in the system is convinced by their education and training that these dating methods work, and therefore dating laboratory scientists or geologists who keep getting bad results may think that the problem is with them.

2. As creationists are fond of pointing out, radiometric dating is complicated by geological processes such as metamorphism and weathering, which can interfere with the assumptions that the dating methods use. As creationists do not point out, though, geologists know this.

Creationists understand that geologists know this and perhaps it is a failing not to mention that they do. In most cases when creationists mention the effect of geological processes on radiometric dating, it is for the benefit of those that do not know this, It would probably be best to make it clear that geologists do know it.

They examine the geological context of where their samples came from to determine whether a technique is likely to be valid, and they experiment with different techniques on different minerals subjected to different conditions to determine which combinations of techniques, minerals, and conditions are valid and which are not.

Their validity or invalidity is based on the assumptions of uniformitarian geology and as such this only proves the point of the claim. The fact is that placement in the geologic column is a major part of the uniformitarian geological context. This shows that the claim is basically accurate. No one is claiming dishonesty, but it is all part of the theoretical system behind radiometric dating.

Many so-called discordant dates are results from such experiments dishonestly portrayed as ordinary field measurements.

No dishonesty here, they are simply presented as existing. Clearly under uniformitarian geology they are not valid, but the fact that such measurements exist shows that there might be a different interpretation to radiometric data. What is important is the fact that discordant dates exist, and that uniformitarian geologists try to experiment with different methods to find those they consider valid. The validity of a measurement is based on uniformitarian geology, and so the claim is essentially correct.

All measurement techniques, from rulers to neutrino detectors, are invalid in some contexts. That does not make them invalid in all contexts. Woodmorappe and others who cite discordant radiometric dates are claiming that the method is entirely useless because it does not apply to some contexts.

Talk Origins clearly does not get the point about citing discordant radiometric dates. The point is that the validity or invalidity of a given radiometric date is based on the assumptions of uniformitarian geology. The citing of discordant radiometric dates simply shows that radiometric dating is not perfect and it shows that at least some degree of filtering does go on. How much is hard to tell. Most people only see the final published dates and not those that result from experimenting with different methods, and the fact that geologists do experiments that get discordant dates shows that there might be another way to look at the results.

3. The factors that one must consider when doing radiometric dating were ignored by Woodmorappe. He ignored geological context and well-known limitations of dating methods.

Actually, Woodmorappe is not ignoring geological context or the limitations of dating methods but simply looking at them from a skeptical viewpoint. The fact is that both are largely based on uniformitarian assumptions. Talk Origins is ignoring the fact that Woodmorappe and other creationists look at this data in a different theoretical system in which those uniformitarian assumptions do not apply.

His analysis is further flawed because
  • he uses obsolete data, such as data from years when the technique was still being developed.
It could be argued that he used data from before the "fix" was in. The development of the technique could have meant an improved filtering of discordant radiometric dates.
  • his treatment of individual cases is extremely superficial.
This is a rather vague statement, and the cases he presents in his book are anything but superficial.
  • his paper is written as propaganda, not as a technical analysis. If he believes what he writes, he should publish it in journals for professional geologists, not for creationists.
Actually the book is quite a good technical analysis. The reason for publishing it in a Creationists' journal was that it is mainly of interest to creationists. If he is correct, a journal by uniformitarian geologists would not publish it for the same reason they would not publish discordant radiometric dates. In any case, Talk.Origins is showing its bias by drawing a false distinction between "professional geologists" and "creationists." The groups of "creationists" includes (some) "professional geologists." The paper was published in a peer-reviewed scientific journal, that is available for professional geologists—creationist or otherwise—to read.
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