Radiometric dating as practiced is reliable.

Thanks to my opponent for the opportunity to look into some of the fundamental aspects of radiometric dating. I found it interesting and I hope readers will find the science interesting as well. I should have explained my reference numbering system. I number references in sequence from the start of the debate, so there is only one ref [n]. So [2] and [3] referenced in R3 are the standard texts I cited repeatedly in R2. The numbering continues with [7] in R3. I'm sorry for the confusion. What does reliable mean? The point of my analogy with using a tape measure was to show that a method can be reliable despite there being a number of possibilities for errors. Con's case comprises a list of things that might go wrong with radiometric without evidence that they typically do go wrong or that they are substantial. Failure to properly align the free end of a tape is comparable to failure of assumptions of initial conditions in radiometric dating. Con cited the possibility of tiny variations in radioactive decays rates. The possibilities of a tape measure stretching or expanding and contracting with temperature are comparable to tiny variations in radioactive decay rates. The objections are uncommon insubstantial, respectively, and so do not invalidate the methods. I think Con is claiming that radiometric dating should judged reliable only if it provides a perfectly accurate measurements every time it is used, no matter the circumstances under which it is used or whether it is used correctly. By that standard, no method of measurement is reliable, We surely could not rely on tape measures, clocks, or thermometers because each has limitations on when and how they are used that require care in their use to get reliable results. We know radiometric dating is reliable because methods using different isotopes cross-check the results, and the results are consistently verified by dozens of non-radiometric methods, ranging from tree rings to optically stimulated electroluminescence. Scientists document problems Con's R2 ref. 1 is a paper that discusses an isolated example of a “fine grained” rock that seemed suitable for K-Ar dating, but yielded an incorrect result. The paper dates from 1971, and did not use the now-common practice of sampling a single crystals to minimize errors. Nonetheless, obtaining an erroneous result merited a publication to report the event. All radiometric dating methods require careful use. Publications reveal the circumstances when there are likely to be problems. The publication of an unusual exception shows that the method is reliable overall. Decay rate variations are insignificant Con cites publications that show a periodic variation in decay rates with solar activity, probably due to the influence of variable neutrino emissions from the sun. Recall that I cited a large body of scientific literature that verified that radioactive decay rates are constant. [8,9,10] The newly discovered variations produce a peak error of 0.3%, [12. http://www.examiner.com...] and they tend to cancel out over time with the errors varying around an average rate. The accuracy claimed for radiometric dating is rarely greater than 1%, so sources of error much less than 1% do not come into play in any practical way. Con found no evidence disputing the literature that verifies the stability of radioactive decay rates to better than the 1% level required to support the accuracy claimed for radiometric dating. It often happens that scientific methods have bounds on their accuracy. Einstein proved that Newton's Laws are only approximations. Yet Newton's Laws are still used reliably for delicate computations of things like satellite orbits. the limitations are kept in mind so the results say within the bounds of the methods. The reason we are debating the reliability of radiometric dating is to potentially provide hope that creationism is correct and that accordingly the earth is really less less than 10,000 years old. Uranium-lead dating shows the earth to be 4.55 billion years old. Potassium-argon dating and many identifies rocks as having last melted hundreds of millions years ago. Other mineral-based methods work to date rocks from tens of millions to a few hundreds of millions of years old. Argon-argon dating and carbon dating are used for objects dating back tens of thousands to a few million years. So if there limitations in the methods that lead to 0.3% errors in the dates of billions of years of years or hundreds of millions of years, or even of objects tens of thousands of years old, is there hope that the earth might really be less than 10,000 years old? No, a 0.3% error in dates of tens or hundreds of millions years doesn't provide a ray of hope for the young earth. Even if the 0.7% variations found only for beryllium isotopes were rampant, it wouldn't come close to doing the job. Dates are consistent Con found the abstract of a scientific article that includes a couple of different dates derived from radiometric methods and seems to conclude that they are in conflict. My understanding is that geologists are trying to sort out different geological events occurring from a half billion to a billion years ago. A 1998 article shows multiple dates of the West Falkland granite s to be consistently a little more than 1 billion years old. 13. http://jgs.geoscienceworld.org...] The issue in the paper Con sites is the presence of rocks with different dates, not an inconsistency in the dating methods. Initial condition assumptions are valid Con wants to know if the release of gas from molten rock has been experimentally verified, The expansion of gas when pressure is reduced is fundamental physics, and that gas is released in volcanic eruptions is universally observed. It has also been experimentally verified. [14. http://www.psi.ch...] The ultimate proof of the validity of the assumptions behind radiometric dating is its verification by dozens of other methods of dating. Con doesn't seem to have specific evidence that C14 doesn't decay, that c14 does not achieve equilibrium with the environment, or that C14 can be injected into isolated samples. He doesn't have evidence that any of the assumptions behind other methods are substantially wrong. He seems to only claim that they cannot be proved in every case. that doesn't overcome the bottom line that the methods are found reliable when cross-checked. Archaeological dating verifies carbon dating In William Libby's Nobel lecture he presents the results of blind experiments that showed carbon dating to be verified by known archaeological dates and tree rings. Although the Nobel prize committee was convinced, it doesn't measure up to Con's standards. Con cites cautions given by service that performs carbon dating telling archaeologists to collect samples in accord with proper use of the method. It warns that if care is not taken there may be large errors. The reason that we know when errors occur is that there are valid cross-checks, including known historical dates. For example, Egyptian relics were known to within +/- 200 years. Carbon dating provides an accuracy of +/- 50 years for the objects. The warning is that if the carbon dates a outside of the historical interval, then there is probably a problem with the sample collection procedure. It does not mean that such errors occur very often. They do not. It means the method is made more reliable by continual cross-checking. If one were teaching use of a measuring tape, would be wise to include cautions about crosschecking to improve reliability, per the "measure twice, cut once" adage of carpenters. My previous objections to Con's references stand. They are unrelated to the debate. Radiometric dating is not controversial in the scientific community because it is so consistently verified. It is reliable.