Since teaching grammar to children is so challenging, teachers often resort to “rules,” using memory tricks to hammer them home. Because of that, some of you may be cringing at the use of “since” in that first sentence.
The cringers were taught that since “because” has a “cause,” it should be used when a cause-and-effect relationship is at issue. “Since,” they learned, should be used only to indicate the passage of time, and not cause and effect in any form. You can say “Since you went home, I ordered a pizza” to mean that you ordered the pizza after she had gone home (time had passed). But you can’t say “Since you went home, I ordered a pizza” to mean that you ordered the pizza as a result of her going home (a direct relationship between two actions).
Garner’s Modern American Usage calls that “a canard.” The usage of “since” to indicate a connection “has existed continuously in the English language for more than a thousand years,” it says. “Since” in the sense of “because” is one of the “Tombstones” in Patricia T. O’Conner’s popular book Woe Is I, and gets a pass from Bill Walsh’s Lapsing Into a Comma “except in the most formal writing.”
The nuance is that many usage guides accept “since” to mean “because” when the relationship is indirect. As The Associated Press Stylebook says:
Use because to denote a specific cause-effect relationship: He went because he was told.
Since is acceptable in a causal sense when the first event in a sequence led logically to the second but was not its direct cause: They went to the game, since they had been given the tickets.
And since it’s far easier to teach rules than nuance, avoiding “since” when there’s any whiff of “cause” has become a rule for many people, and even some style guides. Here’s a blog post about the American Psychological Association’s style guide, used by many academics:
According to the 6th edition of the APA Publication Manual (p. 84), the use of since is more precise when it is used to refer only to time (to mean “after”). You should replace it with because when that is what is really meant.
That all but screams “rule.” But the APA has its reasons, as the relevant entries say:
Some style authorities accept the use of while and since when they do not refer strictly to time; however, words like these, with more than one meaning, can cause confusion. Because precision and clarity are the standards in scientific writing, restricting your use of while and since to their temporal meanings is helpful.
Since versus because. Since is more precise when it is used to refer only to time (to mean “after that”); otherwise, replace it withbecause.
In other words, when precision is key, think.
You do have to watch out for those times when “since” could indicate either time or relationship, as in “Since you went home, I ordered a pizza.” That ambiguity almost always occurs when “since” begins a sentence and is followed by a past-tense configuration. In those cases, say something else: “Because you went home” or “After you went home.”
Since you want to be clear, thinking about which word to use should be easy; don’t do it just because we say so.