13. Tau (τ), noun; the 19th letter of the Greek alphabet. In mathematics, the little-known nemesis of Pi (π). Where Pi is a mathematical constant denoting the numerical value of the ratio of the circumference of a circle to its diameter (approximately 3.14159), Tau denotes the numerical value of the ratio of the circumference of a circle to its radius, and is equivalent to 2π. Advocates of Tau over Pi argue that the former is a more elemental value in the definition of a circle. Among other things, they note that a circle is a figure whose boundary consists of every point on a particular plane that lies the same distance away from a fixed central point…this distance is the circle’s radius, not its diameter.

So the Tau folk say.

What sort of a debate is this, we non-mathematicians groan. How pointless, how arcane! Why should it matter which symbol we use; twice this, half that. A circle will still be a circle, the first time we draw it and the next, and so on and so forth until the very end.

And having said this, return to what we call the real world—there to labor over our own footling, interminable, exquisitely grave choices between parallel universes.

Meta: