Should I use a comma before "but"?

Should I use a comma before "but" in this sentence:

Nowadays, those two groups do not consider themselves as disabled, but as a minority which uses a different language.

Solution 1:

Yes, use a comma. The rule is:

Use a comma to separate contrasting parts of a sentence.

At first, I said yes, use a comma because you do use a comma to connect two independent clauses. Then I realized the part after the comma really isn't independent, so I changed my answer.

THEN ScotM pointed out rule 15 on the page I cited applies, and he's right. So, answer changed again. Note to self: don't answer comma questions anymore.

Solution 2:

Ultimately, the comma is used to aid the reader in the interpretation of the sentence, in the same way that pauses in speech and changes in inflection would be used for the spoken language. Thus, while there are guidelines (that have been codified by some as "rules"), they are not hard-and-fast. Ultimately you must decide whether the presence of a comma helps or hurts reader comprehension, and whether it helps or hurts the "tone" of the work.

In this regard I'd actually consider discarding the comma after "nowadays" before I'd consider discarding the one before "but". The comma after "nowadays" is not needed for comprehension, nor does it mimic a significant pause in spoken speech (though there typically would be a brief one, since it takes the mouth a non-trivial amount of time to recover from saying "nowadays"), while the comma before "but" does coincide with a pause, plus it signals what would usually be a change in inflection.

But, of course, if you are writing for a journal or some other medium which will be formally edited you should attempt to conform to whatever "standards" are used by those editors. They should be able to provide you with a reference.

Solution 3:

You should only use a comma before "but" if it connects two complete sentences. If it connects a complete sentence to an incomplete sentence, you shouldn't use a comma.

I ate the cake but not the ice cream.

No comma is used because "not the ice cream" is a fragment (incomplete piece of a sentence).

I ate the cake, but I didn't eat the ice cream.

A comma is used here because "I ate the cake" and "I didn't eat the ice cream" are both complete sentences.

Note: Two complete sentences joined together by a comma and a conjunction like "but" or "and" is called a compound sentence.