Should "W" of watch be capitalized as it is starting after a colon?
The Associated Press Stylebook and Briefing on Media Law (2002) offers an opinion that is very similar to the one Father Luke identifies in his answer:
Capitalize the first word after a colon only if it is a proper noun or the start of a complete sentence: He promised this: The company will make good all the losses. But: There were three considerations: expense, time and feasibility.
Words Into Type, third edition (1974) comes very close to fully endorsing AP style on this point, except that its formulation includes a striking (and unexplained) "usually":
Following a colon. The first word after a colon usually should be capped when it begins a complete sentence.
But The Chicago Manual of Style, fifteenth edition (2003) has a substantially different rule:
6.64 Lowercase or capital after a colon? When a colon is used within a sentence [cross reference omitted], the first word following the colon is lowercased unless it is a proper noun. When a colon introduces two or more sentences [cross reference omitted], or when it introduces a speech in dialogue or an extract [cross reference omitted], the first word following it is capitalized.
Kenneth Wilson, The Columbia Guide to Standard American English (1993) seems to side with Chicago:
COLON This punctuation mark (:) can ... (3) let one clause explain another, as in He was late: his car had broken down; ...
And so does Oxford Style Manual (2003), which offers an interesting rationale for the rule it adopts:
5.5 Colon The colon points forward: from a premise to a conclusion, from a cause to an effect, from an introduction to a main point; from a general statement to an example. It fulfils the same function as words such as namely, that is, as, for example, for instance, because, as follows, and therefore: [relevant example:] There is something I must say: you are standing on my toes.
Hodges' Harbrace Handbook (1998) points out the rules used in MLA and APA style:
Style manuals vary in their instructions on whether to capitalize a complete sentence after a colon. MLA permits the use of a lowercase letter, but APA does not. All style manuals, however, use a capital letter to begin a quoted sentence that follows a colon.
Bryan Garner, Garner's Modern American Usage, second edition (2003), too, observes that style guides differ on this point:
Authorities agree that when a phrase follows a colon, the first word should not be capitalized (unless, of course, it's a proper noun). But when a complete clause follows the colon, authorities are divided on whether the first word should be capitalized. ... Although the uppercase convention is a signpost to the reader that a complete sentence is ahead, that signpost generally isn't needed.
Those who follow the lowercase convention typically recognize an exception and capitalize what follows the colon when the colon introduces a series of sentences: "He made three points: He wanted some water. He needed sleep. And he wanted to go home."
I've had time to get used to both styles. When I did freelance book copyediting, every publisher I can remember adhered to Chicago style, with a lowercased first word following a colon unless the following clauses took the form of multiple sentences or appeared in quotation marks or began with a proper noun. But the magazines I've worked for—despite following Chicago on most style recommendations—adopted the AP/Words Into Type initial capping rule.
I think the magazines' preference for initial capping reflected a broader preference for relatively short sentences and paragraphs. This preference never made complete sense to me: it seemed slightly patronizing, as though magazine readers couldn't be expected to read sentences that went on as long as the sentences in books. But "shorter is better" is an article of faith in journalism—and of course, capping after a colon does wonders for reducing the average number of words per sentence when you deal with authors who regularly used colons to introduce complete clauses.
Do not capitalize the first item after the colon unless it's a proper noun, or the start of a complete sentence.
So, in the example in question, sure.
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Watch begins a complete sentence and would, comfortably, be capitalized. The question then becomes: Is the sentence complete? If yes, either a period, question mark, or...
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