Today I have taken it upon me to detail the undeniable necessity of the Oxford comma, aka the serial/series comma, aka the most essential grammatical rule that you will ever encounter. Ever. Suitably, I’ll steal the definition from the Oxford dictionaries: “A comma used after the penultimate item in a list of three or more items, before ‘and’ or ‘or’ (e.g. an Italian painter, sculptor, and architect).”
While a cultured literary connoisseur likely already agrees with me on this matter, amateur grammarians may be wondering what the necessity for Oxford commas is. Consistency? Clarity? An insatiable thirst for punctuation, even when excessive? The answer is all of the above.
The consistency is a key factor, because if all other list items utilise a comma, there’s no logical reason to omit it from the second to last list item. Clarity, in select cases, is also a consideration. When the last two items are not separated by a comma, it appears as though they are related in some way and should thus be considered one item. Or, maybe the last two items are a subset of the previous item. Consider “the pigs, John and Joe” vs. “the pigs, John, and Joe” — the question becomes whether or not John and Joe are pigs.
Let’s examine an example of not using them:
“There were several boxes, containing dogs, hamsters, cats and gerbils.”
Are the cats and gerbils contained within one box? Besides the fact that animals should not be kept within boxes in general, putting a predatory feline in a box with a meek gerbil is probably not a good choice. In this case, the Oxford comma could result in the death of this poor rodent.
Aside from the practical problems, though, notice the distinctly repulsive air of this sentence. Surely even lowly non-grammarians can detect a whiff of distaste, or at least the vague uneasy sense that the sentence has not reached its full potential. Perhaps it’s just my devotion to this grammatical tradition, but I find the look of this sentence frightful and, frankly, appalling. Many a work of great writing has been substantially reduced in quality by a single missing comma.
Make no mistake: Oxford commas should not be a non compulsory stylistic choice, a mere matter of opinion, a dispensable accessory that uses extra ink. No, Oxford commas are not optional.