Matthew Du Plessis: The idea of a multiverse is the stuff of science fiction, which plonks it down firmly in the realm of what the sherry-drinking classes refer to as "low culture", and overtly self-conscious hipsters nervously dismiss as "prolefeed", after the newspeak term George Orwell coined for the artless and stupefying media fed to the proletariats of 1984 , to subdue and neuter their aspirations.

It's hard to imagine science fiction as anything other than aspirational, but enough dystopic predictions of hard-done-by futures exist, I suppose, to provide the doom and gloom necessary to discourage jittery readers from contemplating life beyond the here and now.

But then this idea of alternate universes that more or less mirror our own, the idea of an infinite multiverse in which every possible history and future is real and exists, is also the stuff of hard science, specifically within the many-worlds interpretation of quantum physics, the details of which I am able to hold together in my own mind for but the briefest of instants and ... oh, it's gone again.

Never mind, it's not usually the actual science that prolefeed excels at exploring, but rather its implications. Sir Terry Pratchett, for example, has gleefully entertained suggestions that he is guilty of "literature", but happily describes the many-worlds idea in terms of "the trousers of time": even though someone faced with a decision may choose option A and get dragged down one trouser leg, a whole new universe split off at the moment of decision, a trouser leg in which they chose option B instead.

That's simplifying it to the point of pleasant silliness, but it's a tough concept to sell to people who have their feet firmly on the ground, or stuck in the mud.

What serious implications do you suppose are offered by the idea of "other dimensions" that contain identical versions of us who, where we have taken the high road, have taken the low (or vice versa)?

It's strange what spurs one into thinking about such things, but fortunately for us, much of prole-culture is gratuitously strange.

For instance, the film Justice League: Crisis of Two Earths.

Now, in keeping with the etiquette governing such matters, I'm obliged to offer a SPOILER WARNING. I am about to spoil the plot, so if you plan to watch the film and wish to keep its story a mystery for now then, for the love of all that is escapist, novel and pulp, stop reading at once!

For those still with us, the story of Crisis of Two Earths takes us to a parallel Earth, where the world is held to ransom by evil mirror versions of everyone's favourite (DC) superheroes.

The main villain of the piece is an owlish Batman counterpart, voiced lugubriously by James Woods, who considers this idea of an infinite multiverse, that for every universe in which a person decides at a given time to go left instead of right, there is another universe where they go right instead of left, and another where they go back the way they came, and so on and so forth.

What, then, wonders our arch-villain, is the point of making any decision at all? Doesn't the idea that anything that can happen does happen render the idea of free will irrelevant?

He comes to the conclusion that the only truly free and meaningful action that can be taken is the destruction of all realities, of the entire multiverse. And so he does the only thing he feels he can: he builds a Bloody Big Bomb.

Of course, his plan is thwarted. At the last minute, he is transported, alone, to a barren planet with a less potent version of his doomsday device. Facing the prospect of his own imminent demise, the villain looks around blankly, and shrugs: "It doesn't matter."

Boom! Bright light. Fade to black.

Now, I realise that literary explorations of existentialism aren't exactly new, but tell me this: when last did Jean-Paul Sartre get to blow up an entire planet?