What is the conceptual distinction between coordinating conjunctions and subordinating conjunctions?

Question

While it is easy enough to identify coordinating and subordinating conjunctions by memorizing lists of them, the actual distinction seems arbitrary. Coordinating conjunctions are said to join (among other sentence elements) two independent clauses, while subordinating conjunctions are said to join a subordinate clause to an independent clause. The problem is that it appears to be the very presence of a subordinating conjunction which makes an otherwise-independent clause subordinate. For example, in the sentence... > Stock prices would have plummeted, unless the company issued a public > apology. ...the second clause is only subordinate by virtue of including the word "unless." "The company issued a public apology" expresses a complete thought, but "unless the company issued a public apology" does not. So the presence of the word "unless" explains why the second clause is subordinate, which explains why "unless" is a subordinating conjunction. However, in the sentence... > Stock prices would have plummeted, but the company issued a public > apology. ...the same analysis is not applied. Rather, the word "but" is considered to stand between the two clauses, belonging to neither. This grants independent status to the second clause, "the company issued a public apology," whereas if the word "but" were to be included, it would be a subordinate clause, and therefore "but" would be a subordinating conjunction. A sort of explanatory circularity is apparent, and it's not at all clear to me why "unless" and "but" should be treated differently in these examples. What is so special about the FANBOYS conjunctions that they are said to stand outside of independent clauses, while the rest are said to be part of otherwise-independent clauses, making them subordinate?

Answer 1

This is such a cool question! I love how much you are thinking about this. I'm honestly not an expert on this particular matter, but here is what I immediately notice about the difference created by the use of "unless" vs. "but":

In the first sentence (with "unless"), the second clause is expressing more of a hypothetical idea - a condition that needs to hypothetically be met in order for the first clause to occur. So in terms of the actual meaning of the sentence (beyond general grammar), the full expression of "the company issued a complete apology" is very much dependent on the first clause in order to convey the right meaning (i.e., we don't know if the company actually issued an apology - we aren't declaring this - but rather, that this was the requirement or condition needed to be met in order for stock prices to have plummeted). Additionally, I would note that syntax is more flexible with "unless" than in the case of "but". In other words, the two clauses could be flipped around: Unless the company issued a public apology, stock prices would have plummeted.

In your second example, however, this is not the case. You can't flip the clauses around and include the word "but" at the beginning, and still have a full sentence that reads well: But the company issued a public apology, stock prices would have plummeted. Notice the difference? "But" most definitely is independent of either clause, whereas "unless" definitely belongs with the second clause only. The word "but" also really just serves to contrast the idea presented in the second clause with what's expressed in the first clause.

This is kind of tedious stuff, so I hope I'm being clear. And I know this may not be a full answer to your question, but it's what I've got at the moment! Please let me know if you have any questions about my explanation. I'm happy to explain further (or try to)!

Warmly,

Alissa G.