Pointing Out Reasons with As, Since, For, and Because

The conjunctions as, since, and for tend to be used interchangeably with the conjunction because; however, it’s worth taking the trouble to distinguish them, because their use can sometimes introduce ambiguity or seem stilted (Cook 168, 179).

The relevant meaning of because is “for the reason that” (“Because”).

I wanted to visit Bamakao because I’d heard good things about its music scene.

As and since are often used as substitutes for because.

Locals avoid swimming in the river, as the current is treacherous.

I bought another bag of popcorn since more guests are coming.

But beware of ambiguity when using as or since. In the following sentence as could mean either “because” or “while,” to differing effect: As interest rates soared, our firm moved its operations overseas. Rephrase to avoid the ambiguity.

Because interest rates soared, our firm moved its operations overseas.

Or

While interest rates soared, our firm moved its operations overseas.

Likewise, in the next sentence since could mean either “because” or “at a time in the past after or later than” (“Since”): Since she graduated cum laude, she has received a fellowship for her preferred graduate program. Rephrasing again solves the problem.

After graduating cum laude, she received a fellowship for her preferred graduate program.

Or

Because she graduated cum laude, she received a fellowship for her preferred graduate program.

The conjunction for is sometimes used in place of because but may seem stilted or old-fashioned to some readers (Cook 179): The new committee members were quiet in their first meeting, for they preferred to listen and learn before contributing. If you’re uncertain about using for, you may use because or another conjunction instead.

The new committee members were quiet in their first meeting because they preferred to listen and learn before contributing.

If you use for in the above example, a comma should precede the word. Such a comma is needed whenever a coordinating conjunction (such as and, but, or, for, or nor) connects two independent clauses. If, however, you use because, a subordinating conjunction, then no comma is needed since what follows because is essential to the sentence. (See our post on when to use commas with because.)

For is also commonly used as a preposition, in which form it poses no risk of seeming stilted.

She received an award for her research on gene editing.

Works Cited

“Because, Conj. (1).” Merriam-Webster Unabridged, 2023, unabridged.merriam-webster.com/collegiate/because.

Cook, Claire Kerhwald. Line by Line: How to Edit Your Own Writing. Houghton Mifflin Harcourt, 1985.

“Since, Conj. (1).” Merriam-Webster Unabridged, 2023, unabridged.merriam-webster.com/collegiate/since.