Recently a friend lent me an issue of the magazine What If which contains articles in which the author considers possible alternative timelines, had an historical event occurred differently. These cover a wide range of possibilities from what might have happened if John Kennedy hadn't been assassinated, what if the Gunpowder Plot had succeeded, to what would have happened if Queen Elizabeth I had married.

The speculations are interesting, and this is a game anyone with a knowledge of history can play, but in the end, although the authors are experts in their fields, they can only amount to guesswork. The ramifications of a significant change to history are too complex, and the theories rapidly become no more than one alternative to a vast number of effects which might, or might not, have been realised.

The magazine also carries details of the large number of novels which considered alternative timelines, such as Fatherland by Robert Harris, set in a Britain subjugated by the Nazis, The Guns of the South by Harry Turtledove, where the Confederacy defeated the Union, and Resurrection Day by Brendan DuBois, imagining a world where the Cuban Missile Crisis led to a nuclear war. Of course alternative realities are a staple of science fiction films, and TV series. Indeed the episode The City on the Edge of Forever is regarded as one of Star Trek's best.

However what all these admittedly entertaining books and films omit is that the universe has no interest in human history, and what are regarded by humanity as consequential decisions are irrelevant to the cosmos. If new timelines were to be created they would have to be in response to decisions at the atomic level, and quantum mechanics tells us that such would occur constantly in every atom. Therefore trillions of alternative universes would spring into being every nanosecond, and the same thing would happen in those new creations. This could be true, but seems unlikely.

Perhaps the most appropriate on this subject comes from the the poem The Rubaiyat of Omar Khayyam The moving finger writes; and, having writ, moves on: nor all thy piety nor wit shall lure it back to cancel half a line, nor all thy tears wash out a word of it. By all means enjoy the various notions presented, but they are really nothing but hot air.