The Book Switch Theory

[Jorge_Stolfi]

Fact check: the best guess [Voynich acquired] 30-ish [books from the Jesuits], as explained here: You are not allowed to view links. Register or Login to view.

Thanks for the correction.

An 'ex libris' is generally good evidence that a certain person owned a book.

But my premise is that "good evidence" excludes anything that Voynich could have easily forged.  And AFAIK there is no record of anyone seeing that signature before Voynich got his hands on MS408. 

I know the argument against that being a forgery: "Voynich could not possibly have known how Sinapius's ex libris looked like at the time".  But that argument depends on trusting Voynich.  He may have known about Sinapius all along, and obtained a copy of his ex-libris early on, but then feigned ignorance.  (In general, "evidence" that a forgery is genuine is much more convincing if the victim discovers it himself, rather than having it pointed out by the forger.)

I can see that this is an important point for your hypothesis that book A is not MS408, as it strongly links MS408 to Prague.

Indeed it makes "MS408 = BookA" more likely.  But that also provides a strong motivation for Voynich deciding to forge the signature, or to choose MS408 as the replacement for BookA.   Even a gullible millionaire could have wondered whether MS408 was indeed the book mentioned in the letter.   In that case, Voynich would then "discover" the signature "that he had not noticed before"...

With respect to [C3] and [C4], I guess you will agree that they held one of the two.

I don't see why that would be certain.  Is there good evidence that the "30-ish" books that he acquired from the Jesuits included a book that must have been one of the two?  IIUC, the records of the sale do not say so.  And none of the loose Jesuit ex-libris found in that box at Beinecke fits either MS408 or BookA...

I know that the binding of MS408 resembles that of the books that were re-bound by the Jesuits in the 1800s(?)  How strong is that resemblance?  Could Voynich have forged the binding? (Remember, that was before C14 was even imagined, and AFAIK there has been no C14 test of the glue in the binding yet -- has there been?) 

But even if MS408 was one of the books that were re-bound by the Jesuits, it could have left their hands well before 1911, and reached Voynich in some other way.  He may even have obtained it well before 1911.

If Voynich decided to switch the books (because he had the letter but not BookA, or because he had both but BookA was too obviously not a Bacon original), he would have needed a book that fit the description of BookA in Barschius's letters.  So, if he did not have MS408 already, he may have discreetly hunted around until he found it.  Independently of whether Sinapius's signature is legit or Voynich's forgery.

Again, I don't think that the Book Switch Theory ("MS408 != BookA") is particularly likely.  But I think it remains possible; and my probability is not negligible, because I think that Voynich could have had a $$$trong motivation for doing it, and in my view he was sleazy enough to do it. 

All the best, --stolfi