The "rule" against splitting infinitives appeared in the 1800s, but it wasn't initially put forth as a rule. See what was on Henry Alford's mind when he advised against the construction.
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. ‘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, however, 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’m going to really sock him in the kisser,” means it’s going to be quite a punch, but “I’m really going to sock him in the kisser,” conveys more of a sense of determination than a commentary on the strength of the impending punch. [Note: "I'm going to really sock him in the kisser" is an example of a split verb rather than a split infinitive. "Am going to" is a phrasal modal; it means "will."]
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.]