I'm in a mood today, and I keep remembering that most people don't know about this, so while a good many of us are at home fearing one kind of hazard, let me tell you of the campfire story among mathematicians of another one.

Let us begin, as all good mathematicians do, with premises. First, that as G. K. Chesterton once said, “Poets do not go mad; but chess-players do. Mathematicians go mad, and cashiers; but creative artists very seldom. I am not, as will be seen, in any sense attacking logic: I only say that this danger does lie in logic, not in imagination.”

Second, let us remark on the sheer number of prominent logicians and statistical mechanists that have gone mad and ended their own lives, or died in an insane asylum. Among them we count Goedel of his sentence, Cantor of his set and his infinities, Mayer, Boltzmann, Lewis, Ehrenfest, Kaczynski (better known for his other work), Hausdorff, Lyapunov, Turing.

With this firmly in mind, we have what it takes to behold the story of the Black Theorem. The Black Theorem, so they say, is a piece of unearthly logic not meant for even those skilled in navigating the shoals of truths, let alone those mere mortals who have long since fled the field, whether that flight came at the end of a doctorate or in secondary school.

The Black Theorem, as it is told, is a theorem in logic, a *lethal* theorem, which drives its prover (or perhaps its comprehender, though for obvious reasons none are known) to immediate and irrevocable departure from even that tenuous sanity that mathematicians tend to have.

If you doubt me - and you are right to doubt me, as one doubts the teller of any ghost story! - then I still point to the long list of departed hallowed names, and I ask you - if the Black Theorem were real, how would you ever know?