There's been a little kerfuffle lately over danglers. Steven Pinker, who is a noted linguist, said in an article in The Guardian that some dangling modifiers are OK to use — in fact, according to him, they're not even ungrammatical.
What are dangling modifiers, or "danglers" for short, you ask? In a nutshell, a dangler is a little phrase — not a complete sentence — that is used at the start of a sentence to describe something, but that something is not the subject doing the main action of the sentence. Since dangling modifiers don't attach to what comes right after them, they "dangle." The result is that they can be read as describing the subject of the sentence when they actually don't, which can be pretty funny, and we must not be unintentionally funny when we are writing.
Danglers can use present participles:
Walking down the street, a statue of King George appeared. [It's not really the statue that was walking.]
They can use past participles:
Trapped underwater, the cook recounted his miraculous rescue. [He wasn't trapped at the time he recounted it, just at the time he was rescued.]
They can use prepositional phrases:
With silver trim and an oversized trunk, Dave knew he'd found his car. [There's nothing wrong with this sentence if Dave, not the car, is the one with silver trim and an oversized trunk.]
They can use other kinds of modifier, too:
Purple with pink polka-dots, she thought it was the loudest dress she'd ever seen. [She wasn't purple with pink polka-dots, the dress was. We assume.]
Obviously sentences such as these are a little problematic. But, according to Pinker — as well as a number of others, including Geoffrey Pullum at Language Log — there are danglers that are perfectly fine. Granted, many danglers are very snicker-worthy because they're ambiguous, but ambiguous is not the same as ungrammatical. There are many perfectly grammatical sentences that are ambiguous — for example, "He asked his son to comb his hair." (Whose hair, son's or dad's?)
Not everything that is ambiguous (and funny) is a dangler, either. Modifiers can be awkwardly placed in other ways: "I saw a boat strolling by the lake." "Scientists have found a chemical that can increase sex drive in spaghetti sauce." "He shot an elephant in his pajamas." These are ambiguously placed modifiers, but not danglers.
So what could make a dangler acceptable? Let's take a look at some kinds of danglers that are used all the time without anyone complaining about them:
With all due respect, you were a bit rude. [No one objects that you couldn't have been rude with all due respect.]
Among other things, the present was placed on the table all by itself. [It's unlikely anyone will tell you that it couldn't have been among other things if it was by itself.]
Considering your behavior this term, you strike us as a very thoughtless fellow. [Few would point out that a thoughtless fellow is probably not considering his behavior.]
Given all that she had gone through, the policeman could have been more lenient. [Did you stop and ask whether the policeman was really given all that she had gone through?]
Speaking of John, did you give his phone back? [Will anyone insist it asks whether you gave it back while speaking of him?]
Frankly, you have not been entirely honest with me. [What sort of a person would reply, "If I haven't been entirely honest, why are you saying I did so frankly?"]
The last example gives the real clue here. All of these are functioning like sentence adverbs. A sentence adverb is a word such as seriously, frankly, luckily, hypothetically, technically, and — although some peevers hate this one for no good reason — hopefully, used at the start of a sentence to give a tone, attitude, comment, or setting for the whole sentence. As it happens, adverbial constructions can involve things other than adverbs. You can also use participle phrases, prepositional phrases, and similar constructions to modify verbs… or to modify the whole setting or presentation of a sentence, as we do in cases such as the above.
We can change those example sentences just a little to make them a bit more obviously snicker-worthy, keeping the syntax as it was:
With all due respect, he spoke rather rudely.
Among other people, John spent most of his time alone.
Considering his options, he made a thoughtless choice.
Given all that had been stolen from her, the policeman didn't bother issuing a fine.
Speaking of mistakes, the grammarian forgot to give his lecture.
Seriously, he is the funniest person here.
You can certainly deliberately read those in ways other than they're probably intended. Does that make them grammatically wrong? No, the grammar is the same. They're just more ambiguous. They could be rewritten — but not because of bad grammar, just because (in case you missed it) we must not be unintentionally funny.
So, having established that sentence adverbials of those sorts are not grammatically improper, let's look at some sentences of the kind criticized as having danglers that really aren't ambiguous. Tell me whether you could really misinterpret these:
Heading out this morning, it was really grey and wet.
Looking at your academic record, this test is the least of your worries.
Without going into too much depth, it's a delicate situation.
To save time, the knives are kept sharp.
In a nutshell, they're not mistakes.
I really do think we all know that "it" was not heading out, "this test" was not looking, "it" was not what was or wasn't going into too much depth, "the knives" were not the things possessing the intention of saving time, and we're not suggesting "they" could be mistakes outside of a nutshell. The only real difference between these ones and the acceptable examples above is that they're not using well-established phrases that we have come to accept. In short, the judgment about their grammaticality is really a judgment of whether they're idiomatic.
Could the sentences be rewritten? Everything can be rewritten. That's irrelevant to questions of grammaticality. The question for good writing is "Could they be rewritten for greater effectiveness?" The answer, when it comes to "danglers," is not always "yes." Sometimes words would need to be added to pacify the peevers without adding clarity; sometimes the conversational tone would have to be altered.
So… go or no go with sentence-adverb danglers? If you're writing for an audience of grammatical vivisectionists, you work is cut out for you, but if you're writing for ordinary people with no axes to grind, just consider the results… and try to remember the difference between ambiguous and ungrammatical.