Expert opinions about the VMS

[Sam G]

Blimey, if I had a dollar for each time someone takes a snidey pot-shot at me in online forums, I'd surely have been able to buy my own Flaming Cross of Goa by now, right? *sigh*

It wasn't intended to be a potshot at you, and I'm sorry that I did not make that clearer.  What I was objecting to was Rene's rather selective criteria for determining who is and who is not an authority in a given field.

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My analysis, I believe, shows that the text cannot be the result of substituting single symbols for letters in the natural order.

This statement, in the first place, means that Tiltman believes it impossible that the text is a simple substitution cipher - an opinion which, I think, is not presently disputed by anyone.

But in the second place, this statement (just by way of definition of a simple substitution cipher) means that Tiltman believes it impossible that the text is a natural flow of a plain text in any language. He adds immediately:

Languages simply do not behave in this way

Removed from context, it's easy to see this as a blanket statement that the VMS could not be a "plaintext" in any language.  But from context it's pretty clear that he was mainly trying to make a point that it could not a be a simple substitution cipher presumably of a European language.  The idea that the VMS could be written in some kind of very unusual (from the European point of view) natural language is not a possibility that he addressed one way or the other in this paper.

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Tiltman concludes:

My analysis seemed to me to reveal a cumbersome mixture of different kinds of substitution

It is not clear whether Tiltman means a complex substitution cipher here or some other thing,

It's clear that his primary point was that the substitution would have to act not on individual letters, but on whole words or parts of words.  This is the "code book" or "artificial language" idea, and this is precisely what he goes on to describe following these remarks.