It takes boldness to split an infinitive.
You may have heard a rule that you shouldn't split infinitives, but I'm here to tell you it's not a real rule, and the idea itself is based on a shaky foundation.
What Are Infinitives?
To understand split infinitives, we first have to clearly define the word “infinitive.” Wikipedia defines “infinitive” as the unmarked form of a verb (1), but you really need examples to understand what that means. In English, there are two kinds of infinitives: bare infinitives and full infinitives. Bare infinitives are the kind of verbs you usually see in a dictionary, such as
Full infinitives are made up of two words, usually putting the word “to” in front of the bare verb:
What Is a Split Infinitive?
The safest choice is to avoid splitting infinitives.
A split infinitive puts an adverb between the two parts of the full infinitive. “To generously sprinkle” is a split infinitive because “generously” splits the word “to” from the word “sprinkle.”
If you want to remember what a split infinitive is, just remember what might be the most famous example: Star Trek's “to boldly go where no one has gone before.” “To boldly go” is a split infinitive. “Boldly” splits “to go.”
The Latin Origin of the Split Infinitive Rule
Many sources say the origin of the misguided rule against splitting infinitives in English comes from a devotion to Latin that was prominent in the late 1800s. The Victorian Era was a time of great language debate, with dueling dictionaries and people pontificating about language. The conventional wisdom is that people decided that because infinitives can't be split in Latin, they shouldn't be split in English (2).
One of the earliest printed instances of the rule against splitting infinitives comes from an 1864 book called The Queen's English by Henry Alford (3), and through the magic of Google Books, you can see the entry yourself. Alford was the Dean of Canterbury. He had given a series of lectures on language and compiled them into a casual book, which became quite popular.
On split infinitives, Alford wrote, “A correspondent states as his own usage, and defends, the insertion of an adverb between the sign of the infinitive mood and the verb. He gives the instance 'to scientifically illustrate.' But surely this practice is entirely unknown to English speakers and writers. It seems to me that we ever regard the 'to' of the infinitive as inseparable from its verb. And when we have the choice between the two forms of expression 'to scientifically illustrate' and 'to illustrate scientifically,' there seems no good reason for flying in the face of common usage.”
The Common Usage Argument Against Split Infinitives
It may be that Alford was influenced by the unsplittable Latin infinitives, but in his book, he invokes common usage as his reason. It's also odd that he says, “surely this practice is entirely unknown to English speakers and writers,” when he's responding to a correspondent who describes doing it.
If you tried invoking common usage today to argue with the people who think you shouldn't split infinitives, you likely wouldn't get very far. They'd probably say people also use the word “irregardless,” but that doesn't make it right.
Actually, other writers started arguing with Alford about his assertion pretty quickly, but for some reason his dictum caught on with teachers who started teaching it as a strict rule, and some continue to do so to this day, even though you won't find a modern grammar book or style guide that says you should never split an infinitive.
Should You Split Infinitives?
What's a modern working writer to do? If you split infinitives, you'll likely get nasty mail from cranky people who believe it's their job to enforce imaginary grammar rules; so it kind of depends on how much you hate getting that kind of mail.
On the other hand, there's also no reason to deliberately split infinitives when you know it's going to upset people. The safer path is always to avoid splitting an infinitive. I would never split an infinitive in a pitch letter to an editor, for example, because there are certainly editors out there who believe the myth. If you want to get the assignment, don't split infinitives. For the same reason, I'd never split an infinitive in a cover letter for a job.
How to Avoid a Split Infinitive
It is usually easy to avoid splitting an infinitive. Instead of “to boldly go where no one has gone before,” the Star Trek writers could just have easily have written, “to go boldly where no one has gone before.”
You do have to be careful though. Sometimes when you try to avoid splitting an infinitive you can change the meaning of a sentence. Consider this example:
Steve decided to quickly remove Amy's cats.
The split infinitive is “to quickly remove,” but if you move the adverb “quickly” before the infinitive, you could imply that Steve made the decision quickly.
Steve decided quickly to remove Amy's cats.
You could put the adverb at the end—Steve decided to remove Amy's cats quickly—but that seems potentially ambiguous. You may want to rewrite the sentence without the split infinitive to make the same point:
Steve decided to grab Amy's cats and set them free before she got back from the corner market.
That's clear and doesn't have a split infinitive, but it also isn't necessary to rewrite the sentence unless it's important that your writing be as safe as possible. The bottom line is that you can usually avoid splitting infinitives if you want to, but don't let anyone tell you that it's forbidden.
1. “Infinitive,” Wikipedia. http://en.wikipedia.org/wiki/Infinitive#Infinitives_in_English (accessed August 18, 2010)
2. Nordquist, R. “Split Infinitives,” About.com. http://grammar.about.com/od/rs/g/splitinfinitive.htm (accessed August 18, 2010)
3. Alford, H. A Plea for the Queen's English: Stray Notes on Speaking and Spelling. New York: George Routledge & Sons, 1864. p. 171.