Many writers believe that to “split an infinitive” is to break an ages-old grammar rule that has long been set in stone. However, split infinitives are not as taboo as you might think.
First, let’s define what an infinitive actually is. An infinitive combines the root form of a verb with the word “to.” Examples: To laugh, to leave, to fly, to beg, etc. Although an infinitive contains a verb, it does not actually function as one in a sentence. Instead, it can act as an adjective, an adverb, or, most commonly, a noun.
For a very thorough education on infinitives, check out Purdue University’s Online Writing Lab.
An infinitive is considered “split” if a word or phrase comes between the “to” and the verb. The most famous split infinitive in the English language comes from the voiceover narration at the beginning of every Star Trek episode. Even if you’ve somehow managed to avoid ever watching any of the show’s many iterations, you’ll no doubt recognize it:
Space: The final frontier. These are the voyages of the starship Enterprise. Its five-year mission: To explore strange new worlds, to seek out new life and new civilizations, to boldly go where no man has gone before.
The quote contains three infinitives: “to explore,” “to seek,” and “to go.” In the last instance, the infinitive is interrupted by the adverb “boldly.” So why do so many people consider this to be a grave grammatical error?
To answer that question, we’ll have to travel all the way back to 1864. That’s the year when Henry Alford, a British theologian and scholar, published a book called A Plea for the Queen’s English, in which he states that the two parts of an infinitive should never parted. (If you’re curious, you can read the entire text here.)
In Patricia T. O’Connor’s 2009 book Origins of the Specious: Myths and Misconceptions of the English Language, she speculates that Alford based his logic on the fact that in Latin, an infinitive is a single word and therefore cannot be split. Whatever the reason, and despite every grammar guide and usage handbook debunking the rule, it has continued to circulate among English teachers and editors for more than a century. Like its legitimate cousin the comma splice, the split infinitive has a catchy name and an easy explanation, which may have contributed to its longevity. Some wielders of red pens will strike it down, while others will allow the split infinitive to stand.
But the question remains: To split, or not to split?
As with many English grammar rules, our answer depends on context. On the Chicago Manual of Style’s blog, an editor writes that, “euphony or emphasis or clarity or all three can be improved by splitting the infinitive in certain situations.” In essence, if your sentence sounds better or makes more sense with a split infinitive, go for it.
In our famous example, the rhythm and cadence of “to boldly go where no man has gone before” is a subtle improvement over “to go boldly where no man has gone before.” However, Mignon Fogarty (aka Grammar Girl) warns that in certain situations, it’s better to err on the side of caution. In academic papers, grant proposals, cover letters, or other formal documents, avoid splitting infinitives just in case the reader still believes the myth.