This week’s Music Box is ‘tacet’ because it’s ‘Youth Sunday’. ‘Tacet’ is Latin for ‘is silent’, and it’s the music term for ‘don’t play’. In a set of orchestral parts, for example, if the 3rd bassoon doesn’t play, there will be a printed part that says ‘3rd bassoon: tacet’. You’d think this is odd – if they don’t play then why don’t they simply not get a printed part? But in the chaos of rehearsals and distributing sheet music, if the 3rd bassoon doesn’t get a part she can wonder, “Do I simply not play, or did my part get lost?”

It reminds me of those pages in manuals that say “This page intentionally left blank.” But, it’s not blank – it has “This page intentionally left blank” printed on it. Which seems to me something like the classic logical strange loop of “The barber (in a small town) shaves everyone who doesn’t shave themselves.” But then – who shaves the barber? No less than the eminent 20th century philosopher/logician Bertrand Russell (1872–1970) invested a considerable amount of his considerable intellect to this class of conundrums.

In computer programming there are entities called ‘variables’ that are simply containers for values. A numeric variable is one that stores a number (and there are text variables for storing text, etc.). It took a while for computer science to figure out that all sorts of problems are easier to deal with if variables can also store the value “don’t know”, commonly called ‘null’. Null is different from zero – zero is a definite value and null isn’t. For example, “my bank account balance is zero” is quite different from “I don’t know what my bank account balance is” (that is, null).

’Null’ is hardly a new concept, however, considering that it’s been part of Zen Buddhism for eons, or at least since the 13th century. Their word for it is ‘mu’ – their answer for unanswerable questions. For example, their classic koan: “A monk asked a Chinese Zen master: ‘Has a dog Buddha-nature or not?’ The Zen master answered, ‘Mu’”.

In our Western tradition we have a mythology that all questions are ultimately answerable. That’s not so, however. The 20th century mathematician Kurt Gödel (1906–1978) showed that even in the ideal world of mathematics there are always unanswerable mathematical questions – the so-called “Incompleteness Theorem”, a remarkable landmark in the history of mathematics. Gödel’s theorem in one swell foop took a big chunk of Bertrand Russell’s work and drop-kicked it into the recycle bin. And if there are unanswerable questions in the ideal world of mathematics, how much more so in our messy real world?

Meanwhile, when theologians say that God created the Universe out of Nothing (‘ex nihilo’), do they mean S/He created it out of Zero, or out of Null? Or maybe ‘Mu’? Hmm, on that question I think I had better remain tacet.