Cribs in the Voynich MS

[RenegadeHealer]

If the Voynich MS were a regular cipher from the late middle ages, even a relatively complicated one, then these cribs would have been extremely helpful.

Obviously this depends what one means by 'regular'.

I’ll have to let ReneZ speak for himself, but my interpretation of his use of “regular” is “historically documented and precedented”. If the VMs text had many features that drew strong parallels to contemporary ciphers, that would be a strong argument in favor or it being a cipher. But instead, its similarities to contemporary ciphertexts are tenuous and tantalizing, not pervasive. So one cannot rule out the possibility that the VMs in fact isn’t a cipher, but just resembles one, perhaps by design. If it indeed is a late medieval cipher, it must be a highly innovative one in its form and function, the likes of which has yet eluded the historical record.

Mark Knowles, I understand you’ve been doing some in-depth historical research on late medieval ciphers, digging through European archives and other primary sources in person. If there is a “missing link” still in existence — a late medieval cipher with numerous features in common with both the VMs text and well documented specimens — you’re one of the most likely researchers here to have seen it. In any event, I’m curious to see what you’ve found and how it compares, and will definitely buy anything you publish on the topic.

I agree with David Jackson that the work of Ramon Llull, and his students and followers, is a potentially promising lead, when looking for novel ways a late medieval writer might have designed a newer and better cipher from scratch.

The frustrating part of all this, is that comparison to well-documented contemporary ciphers has good positive predictive value, but not good negative predictive value. In other words, finding strong parallels would argue in favor of the VMs text being a ciphertext. But failure to find strong parallels does not rule out that possibility. Which possibility involves fewer additional assumptions for Occam’s Razor to shave away: A) That someone in 1405 designed a very novel and highly effective form of encryption that never took off after the VMs, or B) That someone in 1405 arranged a whole book full of written marks in a way that superficially resembles a cipher, but isn’t one?