I have the greatest respect for punctuation. It is not only useful, it can be enlightening, entertaining, even lyrical. I know that teaching grammar is a lost art in American schools, and recent experience has convinced me that the very idea of punctuation is alien to much of the current generation. So call me old-fashioned, but I am a champion of punctuation, and proud to say so.
In my forty years as a professional writer, I have written millions of words, hundreds of thousands of sentences, tens of thousands of paragraphs, yet despite all that, I remain in awe of, and puzzlement before, the comma. That simplest and most common of all marks of punctuation (a sentence with only one period may have two, three, or more commas), is as ubiquitous as it is ineluctable. And in today's semi-literate popular culture, it is often abused, occasionally overused, sometimes unused by people who have never been trained in its latent and prolific possibilities. This, to me, is a woeful sign of our times, of a verbal culture that is declining at roughly the same rate as cellphone usage is increasing. Recently I read that Elon Musk, that pied-piper of technology, has begun an effort to interface computers with brains to obviate what he calls the slow and cumbersome process of translating thoughts into... language. Simply transporting an idea into speech is, to Mr. Musk, too unwieldy and laborious for the current cyber-spaced-out culture. The mouth, the lips, the tongue, and the vocal chords are too slow for him, and ought to be bypassed in the expression of, what? LOL, BTW, CLD, OTW and RN (which my step-daughter only recently informed me means, not 'registered nurse,' but 'right now').
Even if computer/cranial interface does manage to speed up human self-expression, it is unlikely to do anything to improve the quality or depth of expression. Those who have absolutely nothing to say will be able to say it much faster; indeed, as quickly as their brains can conceive of the latest nonsense, gossip, fads, or insults. Personally I would rather my brain remain separate from my computer, so that I can at least have a nanosecond to think about what I am going to say before I say it. What Mr. Musk considers the slow and laborious process of translating thought into speech may, in fact, be a built-in evolutionary survival mechanism that saves us from making damn fools of ourselves in public.
Well, I have strayed far from my intended topic: the comma. Does anybody really know how it should be used, how it came to be, what it is meant for? Certainly not me. Among those millions of words I have written in my career, there are probably tens of millions of commas, and while some of them must have been inserted correctly, I fear that whole basketfuls of them were either unnecessary or just plain wrong. I have always been very wary of commas, following Hemingway's dictum about adjectives: Mistrust them as you would certain people. In fact, I am downright suspicious of commas, or rather my ignorance of how properly to use them, and so I tend to use them more and more sparingly.
Now, this goes against my early training. I used to love to read turn-of-the-twentieth-century British writing, in which the comma is as omnipresent as Tommies were in the Third World (and just about as stifling of speech). I can recall books by P. C. Wren or Alexander Kinglake (whom Churchill recommended every young man read), or Sir Richard Francis Burton, or Kipling or Conrad or even Churchill himself. All were virtuosos of the comma and they used them elegantly and liberally.
Then along came Hemingway and everything changed. Prose became spare and unvarnished, and oddly bereft of punctuation. He seems to have felt that a writer should use punctuation marks as if they were bullets: only if you intend to do some damage with them. I began reading Hemingway just around the time I was becoming comfortable with the semi-colon, and he quickly put an end to that. The exclamation point he taught me to handle as if it were nitroglycerin. And he began my lifelong wariness of the comma. Oh, he uses commas, of course, but in a sort of utilitarian fashion as if they were nuts and bolts of construction and not enablers of expression. They are meant to tack phrases together, not to adorn or elucidate them, which is what, I suspect, the comma was invented to do.
As far as I know, the comma was born as a breathing mark in ancient Greek. It was placed in front of an initial vowel to indicate that one should aspirate it, that is, exhale as one pronounced it. (For example, the definite article ὁ was pronounced "ho," and ἣ was pronounced 'hey.') This, if it is correct, would validate the advice once given me by a professor to avoid using commas in short sentences, and, in a long sentence, use them at any point where a person would normally pause to take a breath if reading aloud. This, I have always found, was sound advice, though breathing patterns and reading habits do vary from person to person. And so we are forced back on the legal formulation; namely, where any reasonable person would conclude it necessary to do so. This, however, becomes less and less reliable as a criterion since, as our politics show, reasonableness is a withering fruit of virtue.
Take for example the following run-on sentence: 'In any very long, tedious sentence, commas should be used at points where a reasonable person would pause to take a breath, while reading aloud, since the commas, while not strictly necessary, nevertheless make it possible to read the sentence in a fluid and pleasing rhythm, reinforcing its meaning, and clarifying it, regardless of how long the sentence might be, by breaking it into smaller phrases, each of which has its own duration, integrity, and, even, independent meaning.' Fifteen commas-worth of clarity and convenience, and all the usual rules observed. Kinglake would be proud.
Now this obnoxiously long sentence could just as reasonably be punctuated: 'In any very long, tedious sentence, commas should be used at points where a reasonable person would pause to take a breath while reading aloud, since the commas, while not strictly necessary, nevertheless make it possible to read the sentence in a fluid and pleasing rhythm, reinforcing its meaning and clarifying it regardless of how long the sentence might be, by breaking it into smaller phrases each of which has its own duration, integrity and even independent meaning.' Eight commas, and no less clear and convenient to read -- a net saving of seven commas which might be set aside and better used elsewhere.
From this it should be obvious that, for most purposes, the use of the comma is largely a matter of judgment, opinion, and style. Trying to anticipate how a reader will frame the sentence in his speech or his own mind is, of course, a risky business, and so I think that two principles for comma usage should come into play: In the spirit of Hemingway, use them as sparingly as possible consistent with clarity, but give some thought to the comma's potential to enhance rhythm, meaning, and nuance.
The endless sentence above does contain, however, a few inflexible points of comma usage. The opening phrase, 'In any very long, tedious sentence,' is, of course, a misplaced prepositional phrase used as an introduction, and must be set off by a comma. Likewise, the phrase, 'very long, tedious,' requires a comma to separate the two sequential adjectives, 'long,' and 'tedious.' However, in my writing I find that these separational commas are less often necessary than the formula would require. If the sentence read, 'In any long, tedious ambling-on-forever sentence,' one could argue that there should be a comma between 'tedious' and 'ambling-on-forever,' since they are both adjectives; but to my mind, the phrase reads better without this particular comma. To me, there is a clear distinction between a simple adjective like 'tedious' and a synthesized compound adjective like 'ambling-on-forever,' and so there is no chance of mistaking the meaning since the latter is organically linked to the word 'sentence.' This is so, I think, because compound adjectives, which are often whipped up for convenience sake or for expressiveness or rhythm, are almost always placed right next to the nouns they modify, and are, therefore, organically connected to them.
And here, I think, I may have stumbled on a new comma rule: If sequential adjectives are mechanical in their relation to each other and to the noun - just straightforward modifiers - separate them with commas; but if their connection to the noun is organic, let them flow together. I don't find any problem (from a punctuation viewpoint) in writing: 'Donald Trump's incessant, juvenile, gratuitous drunken-binge-like tweets are beneath the dignity of his office.'
Which brings us to the conundrum of the Oxford comma, and here we encounter what can only be described as a cultural difference. In British writing, all the elements in a list of things need to be set off with commas, as in: 'The first, second, third, fourth, and fifth tweets were bad enough; but the sixth, seventh, eighth, and ninth were killers.' The Oxford comma is the comma which proceeds the 'and' in the list. It is usually not used in American writing, the feeling being that it is not necessary for clarity or meaning. But in my writing I have often found that it is necessary, as in the phrase above: 'The mouth, the lips, the tongue, and the vocal chords...' Not using the comma before 'and' in this case tends to lump 'tongue' and 'vocal chords' together as a single organ, when my intention was to separate them as distinct parts of the list. It is a judgment call based on intended meaning; a nuance which the comma makes clear. At times it is useful; at other times, unnecessary. And so, given that one either uses the Oxford comma or one does not, I do tend to use it. Better safe than sorry; better clear than cloudy.
The comma does, of course, have certain prescribed and formal uses, as, for example, to set off nouns or phrases in apposition, and to indicate nouns in direct address. I am a great believer in these, although apposition has proven to be a matter less of formula than of usage. But direct address by all means. 'Shut up, you damn fool!' is necessary and clear. The comma makes it certain that we are addressing an individual, say, Donald Trump. And there is, of course, the popular example of the deadly effect of a lack of a comma as in: 'Let's eat grandma!' While members of a few tribes in the outbacks of the world might actually mean this, the sentence normally should read, 'Let's eat, grandma!' the comma marking the difference between civilization and barbarism; indeed, between life and death. Apposition is slipperier. 'Donald Trump, though an embarrassment, is nonetheless president.' The apposition defines or characterizes the subject, and needs to be set off in commas (or, in this case, in something more restraining than that).
But I have found in my writing that the most common use of the apposition comma, to define a noun or pronoun with another noun, is more a matter of convenience than formulation. 'My wife, Betty, is a great cook.' This, as I understand it, is correct, yet I find the commas here intrusive rather than necessary and, surely, not elegant. To my eye, the sentence reads better: 'My wife Betty is a great cook.' There is no possibility for misunderstanding without the commas, and, indeed, in the current politically correct climate, their presence can become downright confusing. 'My wife, Frank, is a great cook' should mean that I am telling someone named Frank about Betty. But now it is perfectly correct to say, 'My wife Frank is a great cook,' and no one but a fundamentalist Christian will be either confused or perplexed. Thus does progress push or punish punctuation.
If you have read this far, then you must be as fascinated by and frustrated with punctuation as I am. There is much more that can be said about the use of the comma, but I will forego that and simply add that among the best writers all rules of grammar, punctuation, syntax, diction, and even spelling are up for grabs. Good writers, and especially great writers, act as if punctuation should be the servant of prose and not its dictator. They know that punctuation, like any of the mechanics of writing, is meant to serve the purpose of the piece and not to impose a formula upon it. I have learned over the years that, though there are a few rules in English, they are more often honored in the breach than the observance. In fact, no sooner do I find a rule than an exception immediately appears.
I recall being unsure about the relation between certain punctuation marks and the ends of quotations, so I looked up the rule in the writer's best friend, the Chicago Manual of Style. 'Punctuation marks inside quotation marks; no exceptions,' it said. But that same afternoon, an exception did, in fact, rear its head in my work. I don't recall what the sentence was, but it was on the order of: Don't ever try to tell me "charity begins at home"! Since the exclamation mark is not part of the cliché, then it has to go outside the quotation mark. The same was true for the question mark, as in: You don't know how to sing "Sweet Adeline"? The question mark is not part of the title of the song, and therefore must go outside the quotation mark. And gradually I began discovering others; lots, in fact. Through decades as a writer, I have learned that it is sufficient for English to posit a rule, for English to break it. That is one of the reasons I love the language as I do.
So I think the rule regarding the comma has to be elastic rather than rigid. While one ought to be familiar with the formal rules, and observe them as far as possible for the sake of clarity, the fact is that the use of the comma is a matter of feel more than of formula. Commas, like anything else in writing, ought to serve the purposes of the piece, adding to its clarity, meaning, rhythm, and nuance. They are the humble, breathless servants of poetry and prose, enhancing their beauty and power; not nuts and bolts merely buckling clauses and phrases together. The key to learning to use commas, or any other tools of writing, lies, as Yeats would say, 'Where all the ladders start/ In the foul rag and bone shop of the heart.' Think of commas, then, as pulse-beats in your writing, and you probably won't go too far wrong. Use them as naturally you breathe. And read. Read good writing; pay attention to how the author uses the tools of language and learn from it. Do what the brilliant masters have done, and if anyone challenges your choices, you can do no better than to refer him to my favorite poet, Gerard Manley Hopkins, who wrote among many other gems of punctuation-in-poetry:
Soul, self; come poor Jackself, I do advise
You, jaded, let be; call off thoughts awhile
Elsewhere; leave comfort root-room; let joy size
At God knows when to God knows what; whose smile
's not wrung, see you; unforeseen times rather -- as skies
Betweenpie mountains -- lights a lovely mile.
With everything else wonderful and unexpected, he starts a line with an apostrophe S! Now that's breathtaking.