But sender and recipient both know that it’s a poor substitute for purchasing a card in a shop, writing on it by hand, and then walking to a postbox to post it, because contrary to the cliché, it isn’t really the thought that counts, but the effort – which is to say, the inconvenience. When you render the process more convenient, you drain it of its meaning. ... But the other reason we might not realise some everyday process is broken is that it isn’t broken to begin with – and that the inconvenience involved, which might look like brokenness from the outside, in fact embodies something essentially human.

It turns out that when people make enough money to meet their needs, they just find new things to need and new lifestyles to aspire to; they never quite manage to keep up with the Joneses, because whenever they’re in danger of getting close, they nominate new and better Joneses with whom to try to keep up. As a result, they work harder and harder, and soon busyness becomes an emblem of prestige. Which is clearly completely absurd: for almost the whole of history, the entire point of being rich was not having to work so much.

But Keynes was wrong. It turns out that when people make enough money to meet their needs, they just find new things to need and new lifestyles to aspire to; they never quite manage to keep up with the Joneses, because whenever they’re in danger of getting close, they nominate new and better Joneses with whom to try to keep up. As a result, they work harder and harder, and soon busyness becomes an emblem of prestige.

The futility of this situation – in which the addict’s efforts to regain control send him spiralling further out of control – is the basis of the paradoxical-sounding insight for which Alcoholics Anonymous has become famous: that you can’t truly hope to beat alcohol until you give up all hope of beating alcohol. This necessary shift in outlook generally happens as a result of ‘hitting rock bottom’, which is AA-speak for when things get so bad that you’re no longer able to fool yourself. At that point, it becomes impossible for the alcoholic to avoid surrendering to the unpalatable truth of his limitations – to see that he simply doesn’t have the ability to use alcohol as a strategic tool to suppress his most difficult emotions. (‘We admitted,’ reads the first of the Twelve Steps, [that] ‘we were powerless over alcohol – that our lives had become unmanageable.’)

He might have been a genius, but he was also a perfectionist: the mosque of his imagination was perfect, and it agonised him to contemplate the compromises that would be involved in making it real. Even the greatest of builders would inevitably fail to reproduce his plans absolutely faithfully; nor would he be able to protect his creation from the ravages of time – from the physical decay or marauding armies that would eventually reduce it to dust. Stepping into the world of finitude, by actually building the mosque, would mean confronting all that he couldn’t do.