- Options
- Login
- Desktop Style
Options
Assumptions baked into the VMS carbon dating
- Assumptions baked into the VMS carbon dating
-
RE: Assumptions baked into the VMS carbon dating
oshfdk > 28-08-2026, 11:28 AM
eggyk Wrote: You are not allowed to view links. Register or Login to view.Yes they do? The individual folios had ranges of +/-35 years. The final combined range has a range of +/-15 years. That's a huge difference.
We will not be on the same page when you are talking about years. Neither, I think, you will be on the same page with the author of the radiocarbon dating report. The test doesn't measure years, it only measures a proportion of carbon isotopes in the sample. These proportions for all the folios are quite close and the range where measurements overlap is wide and well defined, there is no conflict in the source metric and absolutely no reason to believe that the source folios come from two different batches, unless there is some strong evidence for this other than these measurements.
Let me try an analogy. Suppose you have a handful of marbles and you stand right on the edge of water, close your eyes and drop marbles one by one. Some of them end up in the water and make a splash sound, some drop on the ground and don't make the splash sound. As long as they feel the same, how likely it is that there are actually two distinct types of marbles - splash-making ones and silent ones?
It's the same with the MS - the folios look similar, cut to the same size, written with the same kinds of ink and in the same style and their radiocarbon measurement is the same with the variation tighter than the range of uncertainty. How likely is it that there are two distinct set of folios made 50 years apart? Absent some evidence pointing toward this (not the radiocarbon dating, which doesn't point toward this at all), I'd say this is very unlikely. -
RE: Assumptions baked into the VMS carbon dating
Jorge_Stolfi > 28-08-2026, 11:32 AM
(28-08-2026, 09:50 AM)Koen G Wrote: You are not allowed to view links. Register or Login to view.It's much less separate objects than you'd think. You can get several bifolios out of the same skin.
But it seems unlikely that the author would have acquired uncut whole skins.
It brings us back to the discussion of how vellum was marketed. A survey of manuscript page sizes by Rene showed that You are not allowed to view links. Register or Login to view. close to sqrt(2) like the ISO A paper sizes, suggesting that it was some sort of a standard of commerce. That aspect ratio has the property that if a sheet is cut or folded in half, each half is similar to the original, just rotated 90 degrees.
Opinion differed on whether the sizes were clustered too. I thought I saw clustering around certain values spaced by a factor of sqrt(sqrt(2)), like the modern A and B paper size series interleaved; but others just saw a continuum of sizes.
Anyway, the Author probably got sheets that were already cut into rectangular shapes. Maybe most were already of the right size, or maybe he had to trim some and cut others in half.
But some of the sheets were clearly "off-cuts" with an irregular edge, where the piece ran into the edge of the whole skin.
Quote:And as far as I'm aware, nothing in the VM shows that some skins are of a different supply. They are all of similar size and quality.
The fold-outs have very different sizes. They in particular seem to have been made by cutting large off-cut pieces to the height of the book, or (in the Rosettes case) twice that height.
And the bifolio f115+f105 is a whole centimeter shorter (vertically) than the others.
And the quality seems to vary a lot. Weren't there reports from Beinecke visitors that the folios have variable thickness and stiffness?
All the best, --stolfi -
RE: Assumptions baked into the VMS carbon dating
Oscroft > 28-08-2026, 11:37 AM
(28-08-2026, 09:50 AM)Koen G Wrote: You are not allowed to view links. Register or Login to view.It's much less separate objects than you'd think. You can get several bifolios out of the same skin. And as far as I'm aware, nothing in the VM shows that some skins are of a different supply. They are all of similar size and quality.
I'm not an expert in C14 dating (though I do have some education in the science behind it), and I also have no expertise in medieval writings (just a fascination with historical mysteries, and a love of the past - which, coincidentally, grows as I get older
).
But, I'm quite sure the C14 experts together with the historical experts at the Beinecke (and elsewhere) fully considered exactly the points above along with other points mentioned in this thread. And people trying to challenge their conclusions really need to examine carefully the range of information and reasoning that went into those conclusions - there's a lot more to it than a table of historical dating estimates (plus a bit of science that most of us don't understand).
When we use modern technology, we don't just add another guess to the list of previous guesses and value them all equally. We refine and replace the old estimates that were based on far inferior knowledge. So, for example, old Wilfrid's Bacon-era claim is of documentary interest only - we know it's wrong. Anything prior to the C14 dating surely has to be erased from the range of dates we should consider today.
For me at least, between 1404 and 1438 CE with a 95% probability simply *is* the established dating of the parchment. And a contemporary evaluation of the handwriting by those who understand it *is* the established dating of that part of the question. Unless and until better technology or greater expertise should overturn either.
So do I think amateur sleuths like the regulars on this forum should just accept that and move on? Oh no, not at all. While I see little chance of any current alternative proposals coming good, we can't say for sure. Maybe one day...
-
RE: Assumptions baked into the VMS carbon dating
eggyk > 28-08-2026, 11:49 AM
(28-08-2026, 11:37 AM)Oscroft Wrote: You are not allowed to view links. Register or Login to view.But, I'm quite sure the C14 experts together with the historical experts at the Beinecke (and elsewhere) fully considered exactly the points above along with other points mentioned in this thread. And people trying to challenge their conclusions really need to examine carefully the range of information and reasoning that went into those conclusions - there's a lot more to it than a table of historical dating estimates (plus a bit of science that most of us don't understand).
Unless the justification for their underpinning assumption that the seperate folios can be considered a single object is explained in more detail within their report - which we do not have access to - I already directly quoted their entire reasoning, which was effectively "one can argue that this is the case". Which, by the way, implies that one can argue it isn't the case.
And again, i'm not disputing the individual results for the samples or their processes. I don't know how I could have made this clearer. I wrote an entire intro dedicated to clarifying that I have no issue with how carbon dating is carried out. -
RE: Assumptions baked into the VMS carbon dating
Oscroft > 28-08-2026, 11:54 AM
(28-08-2026, 11:49 AM)eggyk Wrote: You are not allowed to view links. Register or Login to view.Unless the justification for their underpinning assumption that the seperate folios can be considered a single object is explained in more detail within their report - which we do not have access to - I already directly quoted their entire reasoning, which was effectively "one can argue that this is the case". Which, by the way, implies that one can argue it isn't the case.
Oh, absolutely. Free and open access to the entire report (I've no idea how restricted it is) would be a boon to general understanding. If that full access isn't freely available, it leaves it wide open to speculation. But I suspect the C14 testers didn't go into detail in that front - it's not their expertise - and just tested the samples they were given. So I'd really like to see the Beinecke people explain their reasoning on that point - I don't know if that's available? -
RE: Assumptions baked into the VMS carbon dating
Oscroft > 28-08-2026, 12:06 PM
(28-08-2026, 11:49 AM)eggyk Wrote: You are not allowed to view links. Register or Login to view.I wrote an entire intro dedicated to clarifying that I have no issue with how carbon dating is carried out.
PS: My response wasn't intended as a criticism of your initial post, which I thought was well explained and objectively open - I should have been clearer. It was a more general critique of the growing habit these days of dismissing expertise (which extends way beyond our subject area here). -
RE: Assumptions baked into the VMS carbon dating
asteckley > 28-08-2026, 01:07 PM
Looking over your responses in this thread -- not only to my comments, but to others as well-- it really seems like you are not grasping certain aspect about the approach the Arizona team took, about how measurement errors affect data, about how probabilities work, and how multiple features of the manuscript point to a different prior belief than you are wanting to accept. The reasoning behind the adoption of the single-object assumption is just one of the things you seem to be missing. Granted, it really doesn't help that Hodgins explanations were imprecise, if not overtly misleading.
But on the other hand, several people in this thread (including Stolfi, oshfdk and myself) have independently made some similar points to each other regarding how the probabilities should combine in this context, and why the double mode distribution is less of a concern than you seem to be thinking. And yet your responses suggest you still have a basic misunderstanding of the concepts. If not for that repeated failure, I would be inclined to try to find better ways to explain things. But it doesn't look like it would be a good use of time -- it would be a better use of time for you to just go back and try to better understand what has already been said.
More specifically:
- why it is more likely, even though it's not certain, that the parchment came from a common source and why that likelihood is very relevant
- why the calibration curve is more to blame for some of what you are concerned about than the data (for example, if the curve happened to be shifted by a few years, that whole issue goes away)
- why the fact that some books can indeed be found using different sources of parchment, doesn't hold the weight you are giving it
- why it is more likely, even though it's not certain, that the parchment came from a common source and why that likelihood is very relevant
-
RE: Assumptions baked into the VMS carbon dating
Oscroft > 28-08-2026, 01:12 PM
-
RE: Assumptions baked into the VMS carbon dating
asteckley > 28-08-2026, 01:18 PM
(28-08-2026, 01:12 PM)Oscroft Wrote: You are not allowed to view links. Register or Login to view.
(28-08-2026, 01:07 PM)asteckley Wrote: You are not allowed to view links. Register or Login to view.Looking over your responses in this thread...
Might I suggest you clarify which "you" you refer to? It's not clear when you don't actually quote anyone.
Sorry -- I was referring to the original poster of the thread-- eggyk.
(I had actually tried for a minute, but just couldn't find any single quote to append my remarks to because there were too many that warranted reference.) -
RE: Assumptions baked into the VMS carbon dating
eggyk > 28-08-2026, 05:18 PM
(28-08-2026, 01:07 PM)asteckley Wrote: You are not allowed to view links. Register or Login to view.Looking over your responses in this thread -- not only to my comments, but to others as well-- it really seems like you are not grasping certain aspect about the approach the Arizona team took, about how measurement errors affect data, about how probabilities work, and how multiple features of the manuscript point to a different prior belief than you are wanting to accept.
I'm sorry, but I don't understand how this is the case. There is literally only one issue I have, and that is the calculation of the final average. In fact, not even the calculation itself (which was carried out completely correctly) but whether or not the calculation was appropriate to do in the first place. Again, I literally wrote a whole intro that basically boiled down to me agreeing with basically everything they did.
You seem to believe that I think that the double peak is the crux of the issue, when it isn't. If that peak was completely absent, I would have the exact same criticism of the averaging process. In fact, the example range I gave completely ignored that second peak.
You are also saying I seem to have some prior belief about the nature of the parchment, when I literally don't. Is it not possible to have an issue with this without pushing some kind of agenda? Could you tell me what my supposed prior belief is? It seems it may be coming across as if I believe the manuscript is likely older or younger than the range given, when I am not saying that.
(28-08-2026, 01:07 PM)asteckley Wrote: You are not allowed to view links. Register or Login to view.The reasoning behind the adoption of the single-object assumption is just one of the things you seem to be missing. Granted, it really doesn't help that Hodgins explanations were imprecise, if not overtly misleading.
How have I misunderstood the reasoning? I literally directly quoted the reasoning given. There was no more reasoning given.
(28-08-2026, 01:07 PM)asteckley Wrote: You are not allowed to view links. Register or Login to view.And yet your responses suggest you still have a basic misunderstanding of the concepts. If not for that repeated failure, I would be inclined to try to find better ways to explain things.
I am open to hearing why I am wrong. If I have a misundestanding of a specific concept, please tell me what the misunderstanding is, and I will listen. Telling me that I don't understand doesn't help anything. Like, why are my points incorrect? People keep saying they are without telling me why. You say my points don't hold as much weight as I think they do. Okay, why?
Sorry, it's frustrating and i'm getting defensive because I feel like many of the replies here are outright misrepresenting what I am saying.