Now that the Universe Splitter is out, it might be that a lot more people are going to trip over the word “mu” and wonder about it. Or it might be the word only occurs in the G+ poll about Universe Splitter – I don’t know, I haven’t seen the app (which appears to be a pretty good joke about the many-wolds interpretation of quantum mechanics) itself.
In any case, the most important thing to know about “mu” is that it is usually the correct answer to the question “Have you stopped beating your wife?”. More generally, it is a way of saying “Neither a yes or no would be a correct answer, because your question is incorrect”,
But the history of how it got that meaning is also entertaining.
The word “mu” is originally Chinese, and is one of the ways of saying a simple “no” or “nothing” in that language. It got its special meaning in English because was borrowed by Japanese and appears in translations of a Zen koan titled “Joshu’s Dog” from the collection called Gateless Gate. To some (but not all) interpreters in the Zen school, the word “mu” in that koan is interpreted in a sense of denying the question.
Wikipedia will tell you this much, tracing the special question-denying sense of “mu” in English through Robert Pirsig’s Zen and the Art of Motorcycle Maintenance (1974) and Douglas Hofstadter’s Gödel, Escher, Bach (1979).
However, Wikipedia’s account is incomplete in two respects. First, it doesn’t report something I learned from the Japanese translator of The Cathedral and the Bazaar, which is that even educated speakers of modern Japanese are completely unaware of the question-denying use of “mu”. She reported that she had to learn it from me!
Second, Wikipedia is missing one important vector of transmissions: Discordians, for whom “mu” seems to have have had its question-denying sense before 1970 (the date of the 4th edition of Principia Discordia) and from whom Pirsig and Hofstadter may have picked up the word. I suspect most contemporary usage traces through the hacker culture to the Discordians, either directly or through Hofstadter.
Regardless, it’s a useful word which deserves more currency. Sacred Chao says “Mu!” and so should you, early and often!