Q: So, BK, what about starting a sentence with "but"? Is there a rule for that? Because I do it all the time. But I really don't want to, if it's against the rules. It's just so hard to be good sometimes. —Amanda Joann Smith
A: I once covered this in the magazine and what I wrote then still rings true today, so I’m reposting it. (Oh, and it’s definitely hard to be good sometimes—especially when the world is full of bad grammar, run-on sentences, and ice cream.)
Many grammar buffs will slap you on the hand with a ruler for starting sentences with a conjunction—to them, placing the conjunction (but, and, yet, etc.) first creates a grammatically incomplete thought like a sentence fragment. But that doesn’t mean you can’t or shouldn’t do it.
By Merriam-Webster’s definition, a conjunction joins together clauses, phrases, words, or sentences (that’s right, sentences). Contrary to belief (and probably what your English teachers told you), there’s no definitive rule prohibiting writers from using this great device. A conjunction at the beginning of your sentence will tend to draw attention to itself and its transitional function, communicating certain points clearly and effectively.
You should, however, consider a couple of things before going this route. Would the sentence function just as well without the conjunction opening? If so, don’t use it. Also, should the sentence simply be connected to the previous one? If the two ideas work better as a compound sentence, combine them. If an initial conjunction doesn’t really do anything to help you get across the point you’re trying to make, it’s best to bid it adieu.
But it can sure come in handy sometimes.