At school, like many others I was told that when writing a list you did not put a comma after the penultimate item and before the ‘and’ or ‘or’ preceding the final item. So a grammatical shopping list (are there people who write grammatical shopping lists?) could read ‘apples, pears, blackberries and caviare’, or my favourite crime authors as a schoolboy might be ‘Erle Stanley Gardner, John Creasey, Agatha Christie and Edgar Wallace’. My dear wife, who learned English as a foreign language, was taught likewise.
It wasn’t till much later that I learned about the Oxford Comma. The comma that would come after ‘blackberries’ and ‘Agatha Christie’ in the previous paragraph. The last comma in ‘He went into Rymans to get notebooks, ink cartridges, paperclips, and inspiration.’
Its proponents say that it can avoid ambiguity: eg the sentence “I love my sisters, Claudia Cardinale and Jane Austen” could mean that Claudia and Jane are my sisters. Interesting as that would be, I doubt that many people would come to that conclusion: Claudia’s not the kind of name my parents would have chosen.
People can get exercised about this. But, you might think, it does not have any real consequences, other than whether you think your sentence does or doesn’t flow more smoothly without the comma.
You would be wrong. The Oxford comma (or rather the lack of it) is worth $5 million to the drivers who recently brought a court case against their employers, a dairy in Maine in the USA. The details of the case can be found in the New York Times article at https://www.nytimes.com/2018/02/09/us/oxford-comma-maine.html. In short, the case hinged on the meaning in a state law governing overtime of the following list of exceptions:
‘The canning, processing, preserving, freezing, drying, marketing, storing, packing for shipment or distribution of: 1. Agricultural produce …’
Was ‘packing for shipment’ separate from ‘distribution’, or was ‘distribution’ only involved insofar as ‘packing’ was concerned? The old ambiguity argument. The drivers won. The statute has now been reworded, and semi-colons replace commas in the list: and there’s what you might call an Oxford semi-colon after ‘shipment’, in case you were asking.
The NYT’s attitude to the Oxford comma debate may perhaps be inferred from its description of people interested in it as “punctuation pedants, grammar goons and comma connoisseurs.”
Who’d have thought that a few drops of ink could be worth so much?