Page "Ian Stewart (mathematician)" Paragraph 58

::" Lawyers have a concept known as ' fungibility '.

Things are fungible if substituting one for another has no legal implications.

For example, cans of baked beans with the same manufacturer and the same nominal weight are fungible: you have no legal complaint if the shop substitutes a different can when the assistant notices that the one you've just bought is dented.

The fact that the new can contains 1, 346 beans, whereas the old one contained 1, 347, is legally irrelevant.