How do you connect complete thoughts in a sentence?
Editing grammar for accuracy
The Short Story
Complete thought is the layman’s term for an independent clause, which can stand on its own grammatically and makes sense doing so. Yet, sometimes it’s beneficial to combine complete thoughts into a compound sentence. You can accomplish this with a specific kind of connector word, called a coordinating conjunction, or with certain kinds of punctuation. But for all our sakes, abandon the notion that a comma (on its lonesome) is one of your options.
The Real(ist) Story
Writing doesn’t work well if the writer doesn’t communicate his or her complete thoughts to the reader. Complete thoughts need an actual subject and an actual verb, not decoys lurking in prepositional phrases. Sentence fragments (partial thoughts that may imply complete thoughts) aren’t out of the question, but use them sparingly to avoid choppiness.
The highfalutin name for a complete thought is an independent clause. It may be a complete sentence, or it may be attached to another clause. A clause is a group of words with a subject (which may have others words hanging off of it, like little grammatical gargoyles) and a predicate (which is a fancy name for a verb and any words hanging off of the verb).
But don’t be too hasty, Master Took: some clauses, called dependent (subordinate) clauses, still aren’t complete thoughts. Moreover, a noun isn’t always the subject of a clause. Decoy subjects abound! A decoy subject is often:
a direct object—a noun that’s the focus or “recipient” of a verb’s action or state of being
The warrior’s comrade handed him his shield.
an indirect object—a noun that’s the focus or recipient of a direct object
The warrior’s comrade handed him his shield.
an object of the preposition—a noun that’s the focus of a preposition
The warrior’s comrade returned his shield to him.
an appositive—a word (or phrase) that puts the actual subject in different words (so at least you’re getting warmer)
The warrior’s comrade, a stout fellow, returned his shield to him.
There’s no shame in finding it tough to spot decoys. These matters require a certain level of grammatical understanding. A knowledgeable copyeditor or proofreader is like a blacksmith examining a sword, or an engineer or architect looking at a building, and perceiving how it was constructed—how it works under the surface. With pointers, practice, and perseverance, you can get the hang of grammatical analysis, but some sentences are tricksy. That’s why each editorial pass, and each pair of eyes, helps.
Let’s return to the fray. If you choose to combine independent clauses, you’re forging a compound sentence. There are relatively few ways to go about this properly.
The most popular method is with the coordinating conjunction as a connector word (preceded by a comma to mark the separateness of the clauses):
A, and B.
A, but B.
A, or B.
A, so B.
A, yet B.
A, for [because] B.
The alternative method, to be used selectively because it’s more noticeable to the reader, is punctuation without connector words:
A; B. The semicolon is oft maligned by full stop (period) fetishists and those with low expectations of their readers’ attention spans. This is due to guilt by association with long-winded narrative styles. The reputation may hold a grain of truth, yet the semicolon remains an understated, elegant option for fusing two complete thoughts. The trick is, it works best when the second clause logically follows the first clause very closely, whether in a causal sense (like so), as a restatement, or as a closely related addition (like an extra-strength and).
A—B. I’d recommend the semicolon, or keeping the two independent clauses separate, before resorting to the em dash, because the latter is so obtrusive that better options almost always exist. Technically it’s permissible, as a more in-thy-face version of the semicolon, but I’d try to reserve the em dash for attaching sentence fragments.
A: B. You can use a colon when the second clause offers an illustration or other clarification of the first clause. But before using a colon this way, double-check that it’s necessary to connect the clauses in the first place. Is the relationship between the two thoughts any clearer with the colon, or would a period serve just as well?
A, “B.” It’s a stretch at best to call this scenario—the kind of thing you encounter with dialogue or a direct quotation—a compound sentence. The B clause functions as a direct object of the introductory A clause. (The diminutive creature [subject] told [verb] the woman [indirect object], “I thought you’d be taller” [second clause, direct object].) Strictly speaking, the sentence comprises two independent clauses and naught else, yet it doesn’t make sense standing on its own without the B clause to supply the object. Semantics aside, this option applies only in limited situations involving quotation marks.
Splicing two independent clauses together with a comma, as if it were a semicolon, is a mark either of a grammatical novice or of a fiction writer playing fast and loose with punctuation rules as a style choice. (Commas separating three or more independent clauses in a series, or list, doesn’t count. Just hold tight and wait for that coordinating conjunction right before the last clause.)
If you’re considering a comma to connect two complete thoughts, let me help you: don’t. Please, don’t do it. Find your editorial backbone and lay down the law with a conjunction, a semicolon, or—brace yourself—a humble stop in the form of a period.
Story Time
Take these examples from my Dustsong novella:
The sheep had scattered without a trace, but the sun wasn’t long in its descent.[coordinating conjunction]
The moment passed; the hedge held. [semicolon]
“I’m a fool—I know it.” [em dash]
Yet they dressed more like his mother: each was clothed in a hide tunic that covered neck to knee. [colon]
Godspeed, folks, and happy (re)writing!