Meh. It's "evil", supposedly, because if you add up the first N decimal digits of its fractional part then, for carefully chosen N, you get 666, the Number of t

Meh. It's "evil", supposedly, because if you add up the first N decimal digits of its fractional part then, for carefully chosen N, you get 666, the Number of the Beast. I say we should be using binary rather than decimal -- ten is a terribly arbitrary number -- in which case, of course, all numbers are "evil" other than a few dyadic rationals. Here's a better reason why the golden ratio is evil. As you know, Bob, in mediaeval times the musical interval of a tritone -- three tones, or six semitones -- was called "diabolus in musica", the devil in music. It was called that because it's a highly discordant interval; in equal temperament (which of course they didn't have back then, but hush) it corresponds to a frequency ratio of sqrt(2). And why does that sound highly discordant? Well, basically because there's no simple rational number that's a really good approximation to sqrt(2); for much much more about what's going on here, put "William Sethares" into Google and consider buying his book. In fact, in a certain sense sqrt(2) is the second-worst-approximable-by-rationals irrational number, which is related to the fact that its continued fraction is [1,2,2,2,2,2,2,...]. And what's the worst-approximable irrational number, which would produce an even more dissonant musical interval -- a maximally dissonant one -- something even worse than the devil himself in music? Why, the golden ratio, of course. Continued fraction [1,1,1,1,...]. Evil incarnate. (Note: there are a few half-truths in the above, but only for convenience of exposition.)