On July 21, 2010, Arbitrary Musing, unknowingly "the First" but nevertheless dubbed thus, was born.
Arbitrary Musing was born of two parents, of course, as most creatures were, in a very unlikely event that occurred "somewhere between gastrulation and meiosis II," according to a biologist from the University of Flibbertigibbet.
His father was Arbitror A. Arbitratus, and his mother was one of the nine muses. No one knows which because they all look the same anyway. Or at least that's what Zeus claims. It didn't save him from a fate of a night on the couch as decreed by Hera, though.
No one knows how the two met, but when they did, the craziest of things began to happen, including the inexplicable process of the birth of Arbitrary Musing. Many historians and biologists have teamed up to formulate an explanation, but all have failed and they resorted to enlisting the help of mathematicians and physicians. They all said the same thing, uncannily verbatim: "figuring that out would be like figuring out the Grand Unified Theory of the Universe." In they end, they all gave up, had a few drinks, composed Vogon poetry, and conceived a ridiculous idea called "the Matrix," which all but the mathematicians considered a bad joke.
The union of Arbitror and the muse was recorded but mistranslated as "Random Music," since the translation of Xhosa into Srpski was a field in its infancy at the time. It inspired a new musicological field, starting with Stravinsky's Rite of Spring, going on through Schoenberg's twelve-tone serialism, culminating in the Darmstadt school of avant-garde music, and concluding with John Cage's nonsense, although it is rumored that figures like Pierre Boulez have kept it alive underground. "That music had a chance to find an audience, and it failed," said a well-respected composition professor.
Anyway, I digress.
We all know where the muses came from; Mnemosyne and Zeus. Arbitror came from the land of Protoindoeuropa, from the Italic village of Latin. He hailed from a very old family, and his "deponent" status would attest to that fact.
No one knows how they met. Everyone just figured they bumped together in a statistically perfect "random" event, clashing with Einstein's famous God's dice quote. Poor Einstein. He beat himself up so much he had to be confined to a wheelchair and changed his name to Stephen Hawking.
Arbitror and his wife decided to name their child "Musa Arbitrans," but decided to come up with a more "modern name" (Protoindoeuropa had fallen by that time and the villages had become independent city-states, one of which was huge: the Germanic city-state English), and thus, when their son was born, they named him "Arbitrary Musing"
What now? Who knows? As a very very well-respected calculus teacher said, repeatedly, to great effect, "it's arbitrary."