comma before 'but' [conjunction]: He came early but she came late.

[ElAjedrezEsLaVida]

Between two clauses I had always been taught throughout primary school that two independent clauses within one sentence must be separated by a comma; however I see many writing or typing sentences such as, "He came early, but she came late." as, "He came early but she came late." Is this some new rule or is there more incorrect omission of commas nowadays? Given that I am not entirely old, as I started attending primary school in the early 1990s, I remember that omission of a comma in such cases was absolutely incorrect and was castigated via the lowering of marks of the assignment for each comma omitted, amongst other grammatical errors (e.g. subtraction of one mark per omitted comma).

 

[JulianStuart]

Some punctuation rules cannot be broken. Others are contentious.

One of the resources provided here at WRF, has this to say on the comma/conjunction question. (US English, Capital Community College Foundation:
http://grammar.ccc.commnet.edu/grammar/marks/marks.htm)

Use a comma + a little conjunction (and, but, for, nor, yet, or, so) to connect two independent clauses, as in "He hit the ball well, but he ran toward third base."

Contending that the coordinating conjunction is adequate separation, some writers will leave out the comma in a sentence with short, balanced independent clauses (such as we see in the example just given). If there is ever any doubt, however, use the comma, as it is always correct in this situation.

You will never be wrong using the comma, but on occasion (not this one) it will be accepted by many if you omit it.

 

[MikeNewYork]

Between two clauses I had always been taught throughout primary school that two independent clauses within one sentence must be separated by a comma; however I see many writing or typing sentences such as, "He came early, but she came late." as, "He came early but she came late." Is this some new rule or is there more incorrect omission of commas nowadays? Given that I am not entirely old, as I started attending primary school in the early 1990s, I remember that omission of a comma in such cases was absolutely incorrect and was castigated via the lowering of marks of the assignment for each comma omitted, amongst other grammatical errors (e.g. subtraction of one mark per omitted comma).

Comma use has become somewhat individualized over the last decade or so. I am a moderate comma user. There are heavy and light comma users. I would probably use the comma in your sentence, but because the clauses are short, many would leave it out.

 

[Loob]

I'm a "light" comma user.

Whether or not I used a comma in your sentence would depend on how much of a pause I would make in speech between the two clauses.

He came early, but she came late would equate, for me, to something like a spoken He came early ... but she came late.

 

[Wordsmyth]

[...] Is this some new rule or is there more incorrect omission of commas nowadays? Given that I am not entirely old, as I started attending primary school in the early 1990s, I remember that omission of a comma in such cases was absolutely incorrect [...]

Frankly, many such "rules" that have been taught over the ages are not universal rules at all, but rather the preferred styles of particular teachers. I remember a primary school teacher imposing commas in places that didn't seem at all natural to me; then a couple of years later another teacher stripping my work of commas in those very same places: she hated "commas strung around like Christmas decorations" (by which she often meant more than one in any sentence!), because she claimed they broke up the flow.

I totally agree with Loob: a comma essentially represents a pause. So "He came early but she came late" comes over to me as a flat statement of when the two arrived. Whereas "He came early, but she came late" puts the two statements more in contrast.

Ws