Could you justify spending over £1bn of taxpayers' money on finding out why the universe contains more matter than antimatter? The US National Science Foundation says it can't. So it has pulled out of a project to create an underground physics laboratory in an abandoned mine in the Black Hills of South Dakota.
Fundamental physics projects are a hard sell. You certainly can't plug them for the likely immediate benefits. Cern's Large Hadron Collider (LHC) won't improve your life directly. We won't wake up to headlines shouting that particle collisions have, at last, revealed the source of the iPhone 5. An improved understanding of antimatter is not going to benefit the million Africans who die a year from malaria.
The mine-based experiments are an even harder sell than the LHC. They're not anywhere near as exciting, for a start. While the LHC smashes particles together with the energy of two colliding trains, these are passive, wait-for-decades attempts to trap and identify exotic particles that may or may not exist.
Nor are experiments in disused mines as photogenic or impressive as those at the LHC. The reason for going underground is that these tests require unparalleled isolation: 1,500 metres of rock will stop the universe's cosmic rays - high-energy particles that constantly bombard the earth's surface - from creating false alarms in the experiment's particle detectors.
The South Dakota mine is not just about antimatter; it would also look for dark matter, the elusive particles thought to make up a quarter of the mass of the universe. Another proposed experiment aims to examine a strange and (so far) hypothetical process called neutrinoless double-beta decay. You're still not signing the cheque, are you?
On 12 July, the US National Academy of Sciences (NAS) issued a report declaring that someone should put up the money because the project is
of "paramount scientific importance". The NAS, however, is missing the central point: it's the societal significance that matters.
Human civilisations have always sought knowledge for the sake of it as they mature. This often turns out to be a good idea. Yes, the only motivation of many of these scientists is that they want to find out how the universe works. Yet indulge them, and you raise together with them the people who eradicate smallpox, invent the internet and give you twice the lifespan of those who lived two centuries ago.
Also easy to overlook is the feel-good factor. There is something uplifting about being part of a society that addresses big questions, rather than concerning itself only with where the next bit of profit will come from. It's hard to put a number on it, but the value unquestionably exists.
Anyway, the numbers don't look that bad. UK taxpayers spend about the cost of two pints of beer a year on the LHC: the total price tag, which is shared by European partners, is roughly £6bn. To put that in context, replacing the Trident nuclear missile system is likely to cost just shy of £100bn.
Which cheque are you most proud of allowing the politicians to write?
Michael Brooks's "Free Radicals" is newly published by Profile Books (£12.99)