Her supporters said she was merely setting everything in context. No experiment happened in isolation; quantum mechanics had been hammering that point home for the last hundred-and-twenty years. Asking a Theory of Everything to predict the chance of observing some microscopic event – without adding the proviso that “there is a universe, and it contains, among other things, equipment for detecting the event in question” – would be as nonsensical as asking: “If you pick a marble out of a bag, what are the odds that it will be green?”

Her critics said she used circular reasoning, assuming from the very beginning all the results she was trying to prove. The details she fed into her computations included so much about the known physics of the experimental apparatus that – indirectly, but inevitably – they gave the whole game away.

I was hardly qualified to come down on either side … but it seemed to me that Mosala’s opponents were being hypocritical, because they were pulling the same trick under a different guise: the alternatives they offered all invoked a cosmological fix. They declared that “before” the Big Bang and the creation of time (or “adjoining” the event, to avoid the oxymoron), there had been nothing but a perfectly symmetrical “pre-space”, in which all topologies carried equal weight … and the “average result” of most familiar physical quantities would have been infinite. Pre-space was sometimes called “infinitely hot”; it could be thought of as the kind of perfectly balanced chaos which space-time would become if so much energy was poured into it that literally everything became equally possible. Everything and its opposite; the net result was that nothing happened at all.

But some local fluctuation had disturbed the balance in such a way as to give rise to the Big Bang. From that tiny accident, our universe had burst into existence. Once that had happened, the original “infinitely hot”, infinitely even-handed mixture of topologies had been forced to become ever more biased, because “temperature” and “energy” now had a meaning – and in an expanding, cooling universe, most of the “hot” old symmetries would have been as unstable as molten metal thrown into a lake. And when they’d cooled, the shapes into which they’d frozen had just happened to favor topologies close to a certain ten-dimensional total space – one which gave rise to particles like quarks and electrons, and forces like gravity and electromagnetism.