When adults are ambushed with the concept of grammar, for example, when they meet someone  who goes by the name Grammar Girl, they often reach into the depths of their grade-school memories and come up with something along the lines of “Don’t split infinitives, right?” 

Indeed. Splitting infinitives is a grammar topic, but the “rule” you may have learned against splitting infinitives isn’t as hard-and-fast as you might imagine.

Infinitives are the two-word forms of verbs such as to read, to write, and to illustrate.

• to read
• to write
• to illustrate

What is a split infinitive?

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.” When you split an infinitive, you put something (usually an adverb) between the two parts:

• to diligently read
• to happily write
• to scientifically illustrate

The origin of the split infinitive rule

The idea that you shouldn’t put an adverb in the middle of an infinitive was mentioned earlier but was most prominently introduced by Henry Alford, the Dean of Canterbury, in his 1864 book “The Queen’s English.” [Through the magic of Google Books, you can see the entry yourself.]

Alford didn’t state it a rule though. Instead, in response to a correspondent who liked phrases such as “to scientifically illustrate,” he said he saw “no good reason” to split the infinitive. One reason Alford gave for his belief was that nobody was doing it (He wrote, “. . . this practice is entirely unknown to English speakers and writers.”), but the Oxford English Dictionary disagrees, reporting that split infinitives were widespread at the time.

In fact, many respected writers, both before and after Alford’s time, have employed split infinitives, including Thomas Cromwell, Daniel Defoe, Lord Byron, F. Scott Fitzgerald, Elizabeth Gaskell, Benjamin Franklin, and Elizabeth Barrett Browning.

The Fowler brothers on the split infinitive rule

From this shaky start, Alford’s opinion about split infinitives somehow made its way into the general consciousness and English school books, and it was taught as a rule to generations of children—and journalists, according the Fowler brothers, authors of the popular and enduring 1907 style guide “The King’s English.” Although the Fowlers found the split infinitive “ugly,” they nevertheless felt that prohibitions had gone too far. They wrote, “The ‘split’ infinitive has taken such hold upon the consciences of journalists that, instead of warning the novice against splitting his infinitives, we must warn him against the curious superstition that the splitting or not splitting makes the difference between a good and a bad writer.”

Strunk & White on the split infinitive rule

The rule never stuck with experts. Although I hesitate to say it is impossible to find a credible grammar book that wholeheartedly recommends against split infinitives, I have never seen or heard of such a book. Even The Elements of Style (beloved by the public but often disparaged by modern experts for being overly prescriptive) does not recommend against split infinitives, but instead takes a practical approach: “Some infinitives seem to improve on being split, just as a stick of round stovewood does. [For example] ‘I cannot bring myself to really like the fellow.’ The sentence is relaxed, the meaning is clear, the violation is harmless and scarcely perceptible.”

Split infinitives in formal writing

Even though early objectors claimed that split infinitives were the currency of the uneducated, a 2010 study by Moisés D. Perales-Escudero from the University of Michigan found that some split infinitives are common in formal situations: for example, the phrase “to better understand” commonly appears in academic, magazine, and newspaper writing.

Sometimes you can avoid a split infinitive

Some split infinitives have become set phrases in English, such as Star Trek’s “to boldly go,” meaning that “to go boldly” would sound odd. In the case of a typical split infinitive, though, a writer can usually move the intervening words without much offense: “I’m going to generously frost these cupcakes,” becomes “I’m going to frost these cupcakes generously.”

In less common instances, moving the adverb makes the sentence awkward: “I want to quickly stop at the bank” becomes “I want to stop at the bank quickly.” (A more natural-sounding choice would be “I want to stop at the bank for a minute.”)

In some cases, moving the adverb can also change the meaning: “I want to really hit this one out of the park,” means you want the ball to go as far as possible, but “I really want to hit this one out of the park,” conveys more of a sense of determination than a commentary on actual distance the ball will fly.

Finally, some sentences require a split infinitive: for example, in a 2004 Language Log post, Arnold Zwicky provides an instance in which a writer must split an infinitive: “. . . he expects the staff size to more than double within two years.” You can’t move “more than” anywhere else in that sentence without a major rewrite.

Should you avoid splitting infinitives?

When faced with the clear lack of evidence that splitting infinitives is wrong, but also faced with the almost knee-jerk reaction that is common in the general population— “Split infinitives? Wrong!” (or the vague notion “I’m not sure what split infinitives are, but I think I heard they are wrong,”)—what’s a modern writer to do?

The only logical reason to avoid splitting infinitives is that there are still a lot of people who mistakenly think it is wrong. If you write from a position of power, split your infinitives as much as you want. Be guided by the sound and flow of your sentence. On the other hand, if you have to please others or avoid complaints, it’s safer to avoid splitting infinitives. There’s no reason to deliberately split infinitives when you know it’s going to upset people.

This article originally appeared in OfficePro Magazine, a publication of the International Association of Administrative Professionals.

[Note: This is a revised version of an article that originally appeared on this page on August 20, 2010.]