New Post: "I Do Listen to the Experts. Do YOU?"

[asteckley]

However, we have three more folios, each with a similarly low percentage that the date is after 1450.
This means that we have even greater confidence that the book as a whole is from before 1450.

I've not looked over all the relevant details enough to argue one side of the other of this issue, but there is one minor point is worth mentioning about your comment:

The multiple folios do not really give greater confidence on the date (over a single folio) because they all used the same calibration. And that calibration itself may well be  the largest source of uncertainty in the whole test process.

The calibration used  C-14 levels found in certain tree ring records to infer a conversion to actual dates. (That conversion is also not a proper function, by the way, as there is a bimodal distribution involved -- that is, the same C-14 levels occurred during two different periods in the tree ring data, one of those periods being about 100 years earlier in the early 1300's rather then 1400's. The greater likelihood is the one in the 1400's but the other is not neglible.)

The agreement of the multiple tests DOES increase confidence that all three vellum samples are of the same date as each other, but it does not increase confidence of what date that is. If that assumption that the tree-data is a correct representation is wrong, then so too is the date of all the vellum.

Of course, none of this has any bearing on the issue of when the manuscript was written (and I don't think that has been Rich's point either. I think his point was more in regards to whether the experts did or did not agree with the dates and how the history of their opinions seems to have undergone revision.)

Clearly the C-14 tests give very high confidence that the animals providing the vellum were killed in or around the 15th century. The relevant issue is how late in the game could the vellum have been used in producing the codex.  (So far, I've only seen qualitative arguments one way or the other regarding that. But perhaps others know of some more reliable evidence?)