Fixing an Ambiguous Sentence

Sometimes, when you read a sentence with two modifiers or two antecedents, you can find it confusing to decide which modifier goes with which part of the sentence. Then you have to pause and figure out the most logical meaning. Take a look at this sentence:

The vapor trails were observed dispersing from several ground stations.

https://apod.nasa.gov/apod/ap190408.html

Okay, we have two antecedents here. Were the trails “observed from several ground stations” or were they “dispersing from several ground stations”?

Lots of times you can solve the ambiguity by changing the order of part of the sentence.

• The vapor trails from several ground stations were observed dispersing.
• The vapor trails were observed from several ground stations dispersing.
• The vapor trails were dispersing observed from several ground stations.
• The dispersing vapor trails were observed from several ground stations.
• Several ground stations observed the dispersing vapor trails.
  

The first three are all pretty awkward; the fourth one is better, but it implies the existence of vapor trails that weren’t dispersing. The last one is best, and notice it doesn’t use the passive!

I’ve been cheating on you. Here’s the context:

The atmosphere over northern Norway appeared quite strange for about 30 minutes last Friday when colorful clouds, dots, and plumes suddenly appeared. The colors were actually created by the NASA-funded Auroral Zone Upwelling Rocket Experiment (AZURE) which dispersed gas tracers to probe winds in Earth’s upper atmosphere . AZURE’s tracers originated from two short-lived sounding rockets launched from the Andya Space Center in Norway. The harmless gases, trimethylaluminum and a barium / strontium mixture, were released into the ionosphere at altitudes of 115 and 250 km. The vapor trails were observed dispersing from several ground stations.

Since the context tells so much about the vapor trails, you don’t need to describe them again in the last sentence. Just add the new information; say this:

The vapor trails were observed from several ground stations.

Or

Several ground stations observed the vapor trails.

And here’s a picture:

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The rule:

• “Who” refers to people
• “That” doesn’t.

Here’s a good illustration of why this matters:

Is he referring to the ex-wife or to the phone message? Ambiguity is bad except in poetry and lies.

A writing tip: pronouns are supposed to refer to the closest possible antecedent. That’s why I avoid pronouns. Too easy to lose track of the antecedent.

These are possible alternative sentences:

• …message from an anonymous ex-wife who told me…
• An anonymous ex-wife sent me a message that told me…
• An anonymous ex-wife told me…

I suppose I could add that the doctor appears to be violating patient confidentiality.

I ran into a sentence that’s easy to misunderstand even though it’s written “correctly.”

Here’s the sentence:

Ocean temperatures are also much less variable than surface temperatures, which can swing greatly from year to year, and therefore give a clearer signal of global warming.

https://insideclimatenews.org/news/10012019/ocean-warming-accelerating-sea-level-rise-hurricanes-climate-change-science-review

What is the subject of “gives the clearer signal of global warming”? Is it surface temperatures or ocean temperatures? Put another way, what does the “therefore” refer to, the “swing greatly” or the “much less variable”?

“Surface temperatures” and “swing greatly” are both closer to the “therefore give,” so that’s what the clause should refer to, right? Nope!

I think the writer of this article, Nicholas Kusnetz, (and maybe his editor) are so familiar with the mechanics of the topic that they assumed the readers would already know that the more stable temperatures are better indicators of change.

They expected the readers to jump over two wrong answers to get to the correct reference, a serious mental jolt. Mental jolts are not good. The sentence should have ended:

… and therefore ocean temperatures give a clearer signal of global warming.

Now the reader can’t get it wrong. And that’s how you should write!

PS—I like to include pictures in this blog when I can, so here’s one from the article. Notice that it describes ocean temps, not air temps.:

I’ve mentioned in the past that ambiguity is bad except in poetry. (For more on this topic, put “ambiguity” in the search box in the upper right corner.) When you explain something, you want to be clear. I ran into someone pointing this out in a recent Delaware Mensa newsletter, DelaMensa:

I read the newspaper everyday. —Is that past tense or current tense? Did you read that as “I red” or “I reed”? Both are valid. Context is usually helpful, but what if the paragraph started with that?

He suggested a solution, too. Context. I’m a little wordier; I say rewrite the sentence.

Write your sentences so they aren’t ambiguous!

English, being light on inflections, uses word order a lot. Classical Greek, for example, is heavily inflected, so word order can be played with more than it can be played with in English. They even have a figure of speech called chiasmus, in which they arrange the words symmetrically in the sentence (for example, noun, adjective, adverb, verb, adverb, adjective, noun) and you use the inflections to figure out what refers to what. 

Sometimes getting the word order correct in English can be tricky. I have mentioned where “only” should go several times. (Search for “only” in the search box in the upper right corner to see some examples.)

So this Buckles comic, first panel, gets it wrong, at least in expository writing. Perhaps we’re more relaxed in conversational speech.

The rule is that adjectives go right before the word they modify, so technically, the dog is saying that it’s Paul’s good pair, not good shoes. 

Not a lot of difference there; it could go either way, and you might even make the excuse that “pair of shoes” counts as one word. Well, maybe.

But when you’re explaining something, be on the lookout for ambiguity, and avoid it.