I've written a book which has the following line:

It is this curse which has brought many sleepless nights upon me, for one’s egotistical ambition to be certain of one’s knowledge is the precursor for dissatisfaction and dissociation.

The proof reader/editor left a comment on it, noting that it's not good/common practice to have a comma before for when used as an alternative for because.

Is this true? If so, why not?

  • 1
    You'll have to ask your proof reader.
    – Colin Fine
    Sep 26, 2020 at 21:24
  • 2
    I would disagree. Without the comma, I'm inclined to see "for" as introducing a prepositional phrase rather than a subordinate clause. I find it more easily readable with the comma.
    – phoog
    Sep 26, 2020 at 23:33
  • 1
    I also disagree with your proofreader. Reads fine to me.
    – rcook
    Sep 27, 2020 at 3:01
  • Judging by the answers, this seems to be a case of a (supposed, disputed) grammar-book rule being put ahead of clear and readable writing. Well, personally, this is the sort of English up with which I will not put.
    – A. B.
    Jun 3, 2021 at 15:12

2 Answers 2


Well, I was "scandalised" to find information in favour of your proofreader's opinion! On the ProWritingAid site I found this explanation:

Sometimes "for" can be used as a subordinating conjunction in place of "because". If it starts a dependent clause after the main clause, it shouldn't be preceded by a comma:

She bought more gloves for she was always losing them.

However, if the independent clause that comes before "for" contains a negative verb, you need a comma:

He didn't take his umbrella, for the rain had stopped that afternoon.

On another site I found a more determined "pro comma" opinion:

When “for” is used as a conjunction between two clauses (“for” is the F in FANBOYS) then you need a comma before it. When it’s used as a preposition (e.g., some flowers for my mom) you probably don’t need a comma before it, unless it’s in a list or some other structure that needs commas.

I also found a rule on the PurdueWritingLab about FOR linking two independent clauses:

Use a comma before a conjunction (and, but, for, nor, or, so, and yet) to join two independent clauses.


Use commas to separate independent clauses when they are joined by any of these seven coordinating conjunctions: and, but, for, or, nor, so, yet.

So I presume it is finally a matter of deciding if FOR links an independent clause to a dependent one, or two independent clauses.

Here is the guideline I would personally follow:

A comma always comes before the fanboys when they introduce an independent clause or a complete thought. However, if the fanboys in a sentence do not connect two complete ideas, then we do not use a comma in front of them.

(ius.edu/writing-center site)

Note: FANBOYS is made up of the initials of the seven coordinating conjunctions: For, And, Nor, But, Or, Yet, So.


I would much rather see a comma before the "for" in that usage. The comma to me would mark the distinction between effect and causation, and the pause is mirrored by actual speech: speaking that line aloud, I would naturally insert the pause to separate the two clauses.

Without the comma, the reader easily mistakes "for" as being part of "sleepless nights upon me for", where "for" is a preposition potentially followed by "x number of years" or the likes. When the sentence then continues with "one’s egotistical ambition to be certain of one’s knowledge is the _____", the reader is jolted out of that interpretation and must go back and try to make sense of the sentence.

I would recognize "for" as a word that starts sentences/clauses that imply causation, and that comma tells me as the reader that "for" is the first word of a clause rather than a preposition. The clause can grammatically hold its own as a sentence. It gets a comma, whereas omitting the comma signals that the following is not valid as a complete grammatical sentence. Interfering with this convention disrupts the writing.

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