This is an interesting and hotly debated topic. One web discussion of it, by the name of “Number Symbolism in Bach Cantatas,” gives us some idea of how the issue has fared and suggests that there is an infinite amount of exploration to be done on the fascinating issue of number and number symbolism in Bach. Thomas Braatz, the writer who started the discussion, was especially interested in the question of whether there was a tradition for theological interest in number symbolism in Bach’s day. He cites a book he read called “The Occult Bach.” This appears to be impossible to find, but I believe it is written in Dutch by Dutch musicologists Kees van Houten and Marinus Kasbergen. Another book on the subject was written by Friedrich Smend (1947). Smend argued that Bach used the alphabet as code. Attempts have been made by Ruth Tatlow, among others, to debunk the work of these three scholars on the grounds that the arguments are implausible and implicate Bach in occult reasoning. However, people continue to be fascinated with the incredible ways in which Bach’s music expresses itself in number relations.
Thomas Braatz’s comments on problems finding the source mentioned above are as follows: “The book is based primarily on the work of Marinus Kasbergen and Kees van Houten’s “Bach en het getal” (1985), a book I have tried to order from some German on-line booksellers, but to no avail. Must be a popular book! The other references were to the MGG I, 1028ff and MGG 16, 1971ff (MGG=Die Musik in Geschichte und Gegenwart, the German equivalent to The New Grove Dictionary of Music) Just a few important authors to mention: Arnold Schering, 1940; Martin Jansen, 1937; Friedrich Smend, 1947-8; A. Schmitz, 1950, Walter Blankenburg who wrote one of the articles for the MGG, Henk Dieben (1954-5)”Getallenmystiek bij Bach”. This is all very new to me, but very interesting.” (Braatz from the above-mentioned 2001 discussion based on the question he asked “Was there a tradition for theological interest in number symbolism in the Lutheran Church in Bach’s day?”)
