The 'Chinese' Theory: For and Against

[Mauro]

The prior probability of VMS being 'Chinese' (or some other Far East tonal language) is very low. [...] the clearest evidence we have (as pointed out by @oshfdk) are the illustrations, where nothing resembles anything oriental but fits well with European Middle Ages. This is fully expected under the hypothesis VMS in an European language, weird and improbable if the VMS is 'Chinese', which further decreases the (posterior) probability of 'Chinese'.

Yes, this is the mistake everybody makes.  (Even that prof at the Chinese Academy I contacted by mail back then).  "The vellum, ink, pen are European, the letter shapes are European, the order of writing and parag shape and parag-top gallows are European, the hairdos and dresses and castles and month names are European, 'therefore' the language must be European".

I never said 'therefore the language must be European', so that's a mistake I did not make. But the book itself, given the vellum ink and pen, seems to have been written in Europe or near Europe, so the further from Europe the less probable a language is. For instance I think Hebrew and Arabic could be viable, but less probable than Latin French or German. Then Hindi is less probable than Hebrew and Arabic, and Chinese/Thai/Viet etc. are even less probable than Hindi.

But that 'therefore' is not really 'therefore'.  Those observed facts do not logically imply the conclusion.  They may bias its a priori probability; but, as Bayes said to Holmes, "once you have determined that the forward probabilities of the other hypotheses causing the result are negligible, the hypothesis that has a significantly larger forward probability, no matter how small its a priori probability, will have the largest a posteriori probability." 

All you say is correct, but the fact is that what's observed does nonetheless bias the prior probability against Chinese, and when we then factor in the evidence to get the posterior probability (I think you call it 'forward probability') we are not in the position of Sherlock Holmes, because it has not been estabilished at all that "the forward probabilities of the other hypothesis are negligible", and much less that "the Chinese hypothesis has a higher forward probability" than, say, coded Latin, French, German etc. etc. coded astronomical notation etc. etc. gibberish etc. etc. On the contrary, the evidence of the illustrations disfavors Chinese even more than the prior already does.

Adding [the You are not allowed to view links. Register or Login to view. weirdos] to the Chinese theory further decreases its probability, because now the odds must be multiplied by the probability the two weirdos are actually Chinese signs, which is surely less than 100%

That is not correct. The probability of the Chinese theory(CT) being correct depends on how likely the VMs contents would be if the theory were correct, compared to how likely that would be if the theory were false. The probability of those weirdos being there on page f1r is higher if the CT were true than if it were false.  Because the CT provides a scenario that would result in those characters, while other theories don't.

You defined exactly how the probability of the Chinese theory being correct is treated using Bayes. It's also true, as you said, that if CT is correct, then it's more probable the two weirdos, being upside down, badly drawn Chinese character, will appear on a page. It's also true, I'll add, that if the only conceivable way to get to the two weirdos was to draw two Chinese characters (badly and upside down) then the Chinese theory would gain much support. But there are many ways to get to the two weirdos without invoking Chinese (not my field again, but I seem to remember similar examples were found in European manuscripts, and even a random squiggle added for decoration already explains them). Other theories did not explicitly address the weirdos, but for those theories they are not a necessary part: the theories do not depend on the weirdos being this or that. But in CT the You are not allowed to view links. Register or Login to view. weirdos are the main evidence against the probability hit the theory would take by considering the complete lack of Eastern visual themes vss. the abundance of visual European themes. Using the You are not allowed to view links. Register or Login to view. weirdos partially rescues the Chinese theory, but at a cost: as with every added hypothesis the final probability must be multiplied by the probability of the added hypothesis to be true, which is surely less than one.

So indeed I stand corrected and I could have explained it better: it's not true that adding the weirdos to the Chinese theory decreases its probability tout court. It's instead true that the (unavoidable) decrease in probability caused by the addition of the 'Chinese weirdos' hypotheses is compensated (but only in a small part, imho) by the recovery of some of the probability loss caused by the evidence given by the illustrations.

 But this means the VMS was written in 'China', and for what I know (I can be wrong, of course, not my field!) in the Far East vellum was never used (no clue about gall ink and the pigments).

Indeed the vellum is European.  I am not convinced that the ink is really iron-gall ink (yes, I read the McCrone report!) but it is definitely not the ink that was used in China (known in the West, curiously, as "China ink").  And the writing instrument was definitely a quill pen, not the brush that must be used to write Chinese.

But, again, the VMS was not written directly on vellum.  It would be a very stupid thing, because vellum (especially with iron-gall ink) is hard to erase.  For that and other reasons, it is almost certain that (under any theory) a draft of VMS was first written on paper, and then the draft was copied onto vellum. 

Under the Chinese theory, the (European) Author probably wrote the draft with a quill pen (as he would have been used to) while he was in the remote country, using whatever ink he had available.    But the passage from paper draft to final vellum was done by an European Scribe, and may have happened either in the remote country or after the Author returned home.  

In the latter case, there is nothing to explain.  In the former case, it would be perfectly possible that the Author (or the Scribe, if they were not the same person) had taken in his baggage some vellum, and maybe the ingredients to make the ink (if it is iron-gall).  Explorers in more modern times, like Lewis and Clark, generally carried paper, pen, and ink.  If paper, why not vellum?

It could also have been an European who knew how to make vellum and ink and produced everything directly in China. Everything is possible that is not logically forbidden, but is any of this probable?