Re: Sources of error in Carbon-14 dating?

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Posted by Michael Wendorf on June 24, 1999 at 19:51:10:

In Reply to: Re: Sources of error in Carbon-14 dating? posted by James Allen on June 24, 1999 at 05:07:55:

: : : : Dear Jim,

: : : : I offer the following opinions:
: : : : 1. Cases are never closed in academic circles. That's one of the things that makes us so irritating.
: : : : 2. The fact that some highly respected person agrees with it is not a persuasive argument for the truth of an assertion. The basis for that person's belief might be very persuasive, of course. That's why the basis for his opinion is more important than his name.
: : : : 3. There has been no argument on this board about whether pre-1700 Turkmen textiles exist. There have been inquiries about how we might know whether they exist. I believe such questions are reasonable and that they have answers that are not beyond the comprehension of some of our readers.
: : : : 4. Having gotten similar results from analyzing twice is better than only doing it once, and a lot better than getting very disparate results on two tries. But twice is still a very small number of replications and no lab slob in my field would accept it as final.
: : : : 5. The importance of reproducibility of results depends on the sources of error, which is why I have come back to that question several times. If the errors are from random sources (intrinsic to the instrumentation, variations between samples, weighing errors, etc.), then repeating the measurements on new samples eventually leads to a mean value close to the true value. That doesn't happen with systemic errors. For instance, my bathroom scale is about 2 pounds off, and will give you the same erroneous weight every time you step on it. That's an example of systemic error. Measurements can be very reproducible (that is, highly precise), but inaccurate.

: : : : There may a revolution in progress, but I think it is prudent to know the facts before accepting the conclusions. Those of us who think this way will miss the first couple of trains going into the future. On the other hand, most apparently revolutionary findings turn out to be flawed, so we don't spend a lot of time riding on trains that are going the wrong way, either. That's the tradeoff.

: : : : I still hope that some reader will explain what the sources of error in C-14 dating are, and give their approximate magnitudes.

: : : : Steve Price
: : : : Steve, for what it is worth, Kajitani says the greatest contamination is washing a rug. She asserts that her 20 years of obseration have indicated that washing a rug can make its C-14 date up to 100 years earlier. I personally have wondered about biologic contamination and know for certain that it is in sample preparation and technique that the qualitative percision in C-14 dating is achieved. In point of fact ,after seeing and studying 300+ year old Turkomen material under high magnification, I can tell you that any person so "educated" will be able to differentiate the material. My own thesis concerning overall dimensionality of representation is only lacking sufficient samples to be easily understood. The reason for the whole debate, in my eyes, is the fact that Turkoman material might yet sit atop the aesthetic pyramid in peoples minds and if it does it will have achieved that zenith in our adult lifetimes. That is truly extraordinary and of course carries the passive reward of ego trandference and monetary transference as well. James Allen

: : Dear Jim:

: : Or non passive as the case may be. I will add that I doubt the reason for Rageth's work (or Kajitani's and the Met's)and the debate it raises is your belief that Turkoman material might yet sit atop the aethestic pyramid or that any of this work proves your thesis concerning overall dimensionality of representation, whatever that means. Turkoman weaving can be extremely beautiful. I would submit that it is different from classical persian weaving whether or not by classical we are referring to Safavid carpets. Old Turkomans and Safavid carpets need not be compared apples to apples. However, in your post you implied, and in a previous post stated expressly, that "classical" Turkoman weavings are the equal or are aesthetically superior to Safavid carpets. Certainly, this rises to the level of hyperbole. Some old Turkomans have limited but lush color, others have beautifully subtle and sophisticated drawing including a good sense of dimensionality. A few may have both. But to compare them the greatest Safavid weavings wherein 3 and 4 planes of scrolling design exist in multiple shades and hues of 8 - 12 colors? I think we are getting carried away by ego transference.

: : Kind regards, Michael Wendorf

: : There are non-subjective aspects of aesthetics and dimensionality is certainly one of them. As far as I am concerned essentially all Safavid iconography is borrowed. It was borrowed from the already well established book binding industry with its leather tooled book covers and monumental stone works prevalent in the middle east. Nomadic aesthetics was similarily influenced in the beginning by Chinese textiles but it is where they went with the inspiration that seperates them. Turkoman weaving is mostly a system of designs that manage their internal energies, a true "map" of the universe so to speak. Safavid design celebrated a unique understanding of the universe in a crass representational style. The simple fact is their mental habits of perception and color preferences are very similar to our own while the true desert adapted nomads' perception is alien to ours and their designs are often 180 degrees out of phase with our understanding. The bottom line is that Turkoman weaving probably had developed the aesthetic of 3 dimensionality before it was developed in the west, in Rennaisence painting. No such sophisticed design aesthetic was developed in classical Persian weaving. Safavid weaving was all workshop production produced by large teams of specialists. It really isn't fair to compare them. As for the top of the pyramid? I will let the world decide that as it surely will in time.

Dear Jim:
Your concept of dimensionality and the sweeping conclusions you draw from them have been previously discussed. Let me just say that they are both subjective and, at a minimum, open to debate despite your assertions to the contrary. As just one example, consider that one of the conclusions drawn from the Basel testing is that carpets with the least crowded fields are not necessarily the oldest.
Your astonishing dismissal of all Safavid iconography as essentially "borrowed" and its designs as a "crass representational style" underscores either a fundamental lack of understanding or personal prejudices or both. I do agree the Safavids borrowed from and were influenced by what existed before in a variety of media produced by a variety of sources. What they did to make it their own is not merely representational and certainly no less remarkable that what Turkomans appear to have done in borrowing from and interpreting Chinese, Timurid and other influences. This process appears to have continued in both Persia and Central Asia well into the 19th century.
Finally, I believe your insistence on focusing on some nomadic perception and subjective sense of raw energy to distinguish among weavings of greater and lesser age is personal fancy. What I understand the Basel testing emphasized, and you have vaguely alluded to this in some of your posts, is that the earliest Turkoman pieces have a more complicated structure than later pieces. This more complicated structure runs counter to your theory of pure nomadic genius or spontaneous creation. In fact, further research may prove that early Turkoman weavers and Safavid weavers were attacking the same problems at nearly similar times and even in similar ways. How to produce curved lines (warp depression), how to create steeper angles (offset knotting), how to express new ideas and patterns of rich sophistication. It seems to me less likely that these earliest Turkomans were the raw product of nomadic genius and much more the product of great craftsmen experimenting with looms, wools and dyes of the highest quality.
Best personal regards, Michael

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