One of the most fascinating things about language is that we can use it so well, so expertly, without understanding how we do it.
The following two sentences are perfect examples.
If the burglar was smart, he left the country.
If the burglar were smart, he would have left the country.
Specifically, I’m talking about the difference between “was” and “were” in sentences like these. “Was” suggests it’s possible the burglar had a good head on his shoulders. “Were” suggests he did not.
Any native speaker can pick up on that. But if you asked 100 of them to explain what’s going on with those two verbs, somewhere between 99 and 100 would have no idea.
And if they spent all day reading dictionary definitions they would be no closer to understanding the basis of these different meanings of “was” and “were.”
To understand them from an academic perspective, you need to start with a single word: subjunctive. That’s the grammar term that describes what’s going on here.
The subjunctive is one of two “moods” in English grammar. The other is called the indicative. To oversimplify just a bit, the subjunctive mood is used for statements contrary to fact, whereas the indicative mood is the standard form we use for factual statements.
We can pick up on this contrary-to-fact quality in “If the burglar were smart.” That “were” tells us that he wasn’t. Our suspicions are confirmed as the rest of the sentence plays out, with “would have” left the country, which tells us he didn’t.
But even before we got halfway through the sentence, we knew the burglar wasn’t smart. We knew it because subjunctive “were” slaps that contrary-to-fact quality on the statement.
In “If the burglar was smart,” we don’t know that he was, but we don’t know that he wasn’t, either. It’s possible he was smart — or not. We’ll find out when the cops run his passport number. Until then, his intelligence is a real possibility. It’s not counter-factual.
The contrary-to-fact situations that call for the subjunctive include suppositions and wishes. But demands, commands, suggestions, proposals and statements of necessity are also subjunctive-mood situations.
Forming the subjunctive in the present tense is different from doing so in the past tense. In past-tense forms, the subjunctive applies only to the verb “be” and it manifests in just one way: It changes “was” to “were.”
“Brett was here,” in a wish, becomes “I wish Brett were here.” “I was in charge,” in a supposition, becomes “If I were in charge.”
But you’ll only see the difference in first-person singular and third-person singular subjects like I, he, she and it. The reason? All the other subjects take “were” for the indicative: I was. You were. He was. She was. It was. We were. They were.
The subjects that take “were” in the indicative don’t change at all in the subjunctive: They were here. I wish they were here.
In the present tense, the subjunctive is more complicated. To change the verb from indicative to subjunctive, use its “base form,” which is essentially the infinitive.
If the indicative is “Stella is here,” you would swap out the “is” for the infinitive “be.” “It’s imperative that Stella be here.” If the indicative is “Zeke brings a raincoat,” you would swap out the conjugated “brings” for the base form “bring,” giving you “I suggest Zeke bring a raincoat.”
If that has an old-fashioned or even pirate-y flavor to it, that’s because the subjunctive has partially faded from the language, leaving old-timey forms like “If he be thar at starboard” to history and comical portrayals thereof.