This is a cross post from the Skeptical Analysis blog.
Creationist David Buckna commented on a prior post. One comment included the following three links. I have previously responded to other parts. The following is from David Buckna:
All three links are to pages on the Creation Ministries site. The first was posted last March by creationist Russell Grigg and is titled David Attenborough’s Dawn of the Mammals. Grigg sets out to critique Episode 2 of the TV series, Rise of Animals. He instructs readers on how to avoid being convinced by Attenborough’s presentation. For starters:
In order to show the alleged progress of evolution over millions of years, Attenborough’s tactic is to show fossils of animals with alleged different ‘beneficial’ characteristics in a descending order of alleged ‘long’ ages. These are not the various fossils’ real ages, but are the ages that evolutionists have allotted to the various strata in which the fossils have been found. And how is the age of any particular stratum determined ultimately? Answer: By the fossil(s) which it contains. This is circular reasoning, and such ‘illogic’ would have no validity as ‘evidence’ or be tolerated in any other scientific discipline. It is unique to the theory of evolution. Make no mistake: radiometric dating does not break this circle—there are many examples of radiometric ‘dates’ being trumped by the fossil ‘dates’, as shown in How dating methods work.
Grigg’s initial effort is apparently to cast doubt on deep time. A frequent challenge by creationists, particularly by those adhering to the recent creation of the Earth story in the Bible, is to contradict geologists’ methods for determining the ages of formations. Note Grigg’s use of the wording “alleged ‘long’ ages.” Modern science dates geological formations to the millions and billions of years old. This must be countered by creationists of the first kind.
As Grigg alludes, paleontologists determine the age of fossils by the age of the geological formation in which they are found. This is not unreasonable.
- There usually is no method for direct determination of the age of a fossil.
- The ages of various geological formations can be and have been determined with good assurance.
If an animal fossil is determined to have been encased in a specific formation at the time the formation was laid down, then there is the good presumption the animal died during the time the formation was laid down. The age of the fossil is then presumed to be of the same age as the formation.
Often, geological formations, layers of rock or sedimentary material, encompass large regions. If a study of the entire formation determines there is good certainty the entire formation was laid down during the same period, then varied regions within the formation are presumed, not unreasonably, to be of the same age.
If the location of a fossil find cannot be directly measured, but another region of the same formation can be, then the reasonable conclusion is the fossil is the approximate age of the region that can be dated.
If a geological formation spans a large period of time (bottom part is much older than the top part), then the age of a fossil can be adjusted with respect to the measured point in the formation by assuming some rate of growth of the formation.
If no point in a formation can be dated, then geologists can look to formations that overlay the one in question and also formations below. If the ages of formations above and below can be determined, then the age of the formation in question can be estimated by the bracketing ages. The initial presumption is that formations on the bottom were laid down prior to formations on the top.
This sequence can be skewed, however. There is a geological process called over thrusting. Once formed, two adjacent regions can be pushed together, causing one to overlay the other. This causes some older rock to overlay some younger rock. In other cases a layer can be folded by horizontal force, causing a region to be completely overturned, reversing the order in which the layers were originally formed. Professional geologists recognize when this has happened and make allowances.
Grigg uses this much-abused argument: “These are not the various fossils’ real ages, but are the ages that evolutionists have allotted to the various strata in which the fossils have been found. And how is the age of any particular stratum determined ultimately? Answer: By the fossil(s) which it contains. This is circular reasoning, and such ‘illogic’ would have no validity as ‘evidence’ or be tolerated in any other scientific discipline.” This would make some sense if it were not false at its base. What undoes this argument is that ultimately the ages of formations are determined by radiometric dating.
Grigg needs next to attack the validity of radiometric dating. His link to radiometric dating. is not to a scientific source but to another page on the Creation Ministries International site. Following that, his link to How dating methods work is to yet another page on the CMI site. So far, Grigg has not pointed readers to any reputable sources to make his argument. I am now left with the choice of continuing to follow David Buckna’s chain of links in search of elusive validity or calling a halt to this charade. I’m going to choose the latter.
David submitted a comment to my prior post. That post stated, in part:
I’m continuing a review of comments from creationist David Buckna. I will keep the current title for this series in order to maintain continuity. Additionally the wording tends to reflect the sense of the comments I’ve been receiving.
I stated that I was not going to respond to his lengthy comment all at once, but would piece my response out in manageable bites. This led to an email dialog and the three links I noted above.
Rather than address my original statements directly, David has responded with links to numerous sources of dubious quality. If I pursue this dialog in the manner of David’s choosing I will be left with putting hours of response for each of David’s links to nowhere. My preference would be to have a dialog with somebody who has facts in hand and is willing to make an argument based on these facts. That person is not David Buckna.
Readers are invited to challenge me on this. Why am I not pursuing each of David’s links in turn and spinning out long analyses of each point in these long chains? Fair enough. If anybody reading this wants analysis of a particular claim by David or by any of the sources he has linked to, then I am eager to respond.