The quote “If you remember the Sixties, you weren’t there,” variously attributed (sometimes with slight differences in wording) to various iconic figures of a distinct cultural era, can appear at least seven ways based just on the treatment of the number. Which version is correct?
The answer to the question is a matter of style, a qualitative quality of writing based on precedent or preference, in which a choice is not necessarily right or wrong, though one option usually stands out as most logical. Here’s my judgment about this issue:
1. “If you remember the Sixties, you weren’t there.”
If the decade is to be considered a well-defined phenomenon, akin to the Gay Nineties, the Roaring Twenties, and the like, this style is justified. However, capitalizing Sixties creates an inconsistency if, in the same document or in other issues of the same publication, other single-word references to decades are correctly treated generically, with no contextual emphasis: “The people who became prominent in this era were born during the forties.” But most writers and editors — including me — would accept adjacent references to “the Roaring Twenties” and “the thirties” without question, so this style is my preference.
2. “If you remember the sixties, you weren’t there.”
This option presents a lowercased label for something that is more than the sum of its parts; it is not equivalent to “the years 1960 to 1969” (or, as some people prefer, “the years 1961 to 1970”). The phenomenon arguably didn’t start at the beginning of the decade or end at its close. “The sixties” and “the Sixties” are distinct concepts, and if you understand the context of the quotation, you should agree that the latter concept is the pertinent one. Therefore (and for the reason noted in the next item), this version is unsatisfactory.
3. “If you remember the 60s, you weren’t there.”
A two-digit number rounded off to zero is usually construed to refer to a person’s age. (The spelled-out treatment has the same association, though, as noted above, it also applies to decades.) Furthermore, style guides generally agree, at least tacitly, that this treatment is undesirable, because 60s is a truncated form of 1960s, and the custom is to signal the elision of the first two digits in such a term with an apostrophe. This treatment, therefore, is the only one on this list that is unequivocally incorrect. (And if the pertinent style guide calls for spelling out most numbers below 101, it is erroneous on that basis as well.)
4. “If you remember the ‘60s, you weren’t there.”
This version eliminates any concern about consistency in capitalization between an iconic reference to “the Sixties” and the quotidian term “the seventies,” but it introduces another problem: If you refer to the era as “the ‘60s,” even though it’s not a literal reference to a decade, shouldn’t every reference to a range of ten years in a given document or publication, whether literal or figurative, be in numeral form? Therefore, I don’t consider this the best choice.
Also, I hope you noticed the glaring error I deliberately introduced: As I mentioned in the preceding item, the mark preceding a truncated numerical reference to a decade should be an apostrophe (’), not an open single quotation mark (‘). To correctly punctuate the elision of 19, type any character, press the quotation-mark key to produce a close single quotation mark, type the number, and delete the random character that enabled the correct orientation of the mark to serve as an apostrophe. (Or, more simply, copy and paste an apostrophe from elsewhere in the document — here, from weren’t.)
5. “If you remember the 60’s, you weren’t there.”
When an apostrophe and the letter s follow a term, the implication is of possession, but this statement does not pertain to something belonging to 60. This rule is not timeless — well into the twentieth century, the form shown in this example was standard — but is now widely seen as an aberration, or at best an affection perpetuated, for example, by the dowdy New York Times (which still also inserts the social titles Mr. and Ms. — at least it acknowledged the feminist-fueled alteration of the latter label from Mrs. — before people’s surnames). I consider this option, except when used in such publications that employ the outmoded mode, indisputably incorrect.
6. “If you remember the 1960s, you weren’t there.”
If the consideration is of how to transcribe the quotation of one of the people credited with stating this sentiment, this choice is wrong, because none of them pronounced the word nineteen. However, in any other similar comment, if the context implies discussion of the era, I advise against using this form for the same reason I would avoid the form shown in example number two: 1960s strongly implies the decade, not the cultural phenomenon that occurred roughly at that time. Only “the Sixties” evokes the resonance of the era.
7. “If you remember the nineteen-sixties, you weren’t there.”
Some style guides call for spelling out numbers in quotations regardless of the overall style called for in the document or publication, but my mantra of “Minimize exceptions” is at odds with this idea, so I reject this option.
I just wrote nearly 900 words to analyze how to write one word in a given context. Am I overthinking it? No, though I exerted more physical effort than is necessary: One can think through such a decision in the time it takes to read, much less write, that much text. The point of this exercise, though, is that style decisions should ideally be grounded in solid logic — and once you select your preference on such a firm basis, it is always there for you, enshrined in a style guide for personal or professional use.