‘No darling,’ I said, ‘nothing to do with mushrooms.’ My husband had responded to my exclaiming ‘What does she think that means?’ on hearing Theresa May use the word fungible. This rare word now crops up in discussion of Brexit, perhaps caught from lawyers and business types. They seem to think it means ‘porous, malleable, flexible, convertible’.
Dominic Grieve told the Commons last month that he’d prefer ‘a longer and fungible extension’ to the Article 50 process. Stephen Doughty spoke of a ‘flextension, fungible extension or whatever’. Jo Johnson said on another day that he wanted train tickets to be ‘fungible between operators’. Claire Perry assured the House that ‘scientists are not fungible’. Nick Clegg told the New Statesman that ‘time is the most fungible thing of all’.
The Oxford English Dictionary rejigged its entry for fungible in 2017, with the definition: ‘Of a good that has been contracted for: that can be replaced by another identical item’, or more generally ‘interchangeable’. A quotation from America in 1914 says: ‘When a man puts his grain in an elevator and draws money against that number of bushels of grain he does not necessarily have those particular bushels of grain. They commingle.’ The derivation is from Latin fungi, ‘to perform’, especially as a stand-in.
What’s lost now is a concept essential to the idea of usury. In the 13th century, Thomas Aquinas defined fungibles as ‘things the use of which consists in their consumption: thus we consume wine when we use it for drink’.
In that, wine differs from a book. You can charge someone to borrow a book and use it, and also ask him to give back the book. But it would be strange for a pub landlord to say: ‘Here you are: pint of bitter, £3.70, and I’ll want it back when you’ve finished with it.’
Aquinas and everyone else said it was immoral to charge twice for a fungible thing. People at the time regarded money as fungible in that sense. If money is no longer fungible, it is licit to charge reasonable interest on it, like rent on a house.
I don’t think I’d use fungible if I wanted to be clear. With politicians, that is not always the object.