Quote:many of these theories include opinions that cannot be measured (are unfalsifiable)
I was specifically referring to opinions, and those that cannot be measured. Referring to the wiki page about the scientific method, they do not allow to define experiments from which we learn more about them.
Examples: anything related to the intention of the author(s) / scribe(s) / artist(s).
There are plenty of things that we will only be able to verify once the MS has been translated.
In that sense they would seem to be falsifiable, but not in any useful way. They would not lead to more knowledge before the whole thing is solved.
Questions whether or not person X had anything to do with the MS can be considered falsifiable, even though chances may be slim.
Examples: Averlino, someone in the Barbavara family, or indeed Widemann.
This is where research of documents comes in - libraries, archives.
The case of Widemann (who was of course always envisaged as an early owner, never a creator), is different because his name came from an archival document in the first place, and over time more and more items have been found. Very much research that is still in progress, and the conjecture of his involvement could be broadened to include additional names: Geizkofler, Popp, Rauwolf.
Whether one finds evidence in an archive is only know after the search, regardless how confident one may feel beforehand about the success of the seach.