Infinitives are verb forms composed of two words, such as “to write” or “to understand.” For instance, “I like to write sentences using infinitives” and “To understand infinitives, one should learn when to use them,” are examples of the infinitive verb form.
But say you wanted to make these sentences a bit more descriptive. You can do this by adding an adverb or adverbial phrase to the verb forms, such as “clearly write” or “fully understand.” This may result in “splitting the infinitive,” where adverbs or adverbial phrases are inserted between the “to” and the root verb that follows, as in “to clearly write” or “to fully understand.” Split infinitives are hotly contested in the grammar world. Some grammarians argue we should always avoid splitting our infinitives while others assert splitting the infinitive isn’t a hard rule and can be done if it preserves thought and sentence fluency. Therefore, it’s hard to know when to avoid splitting an infinitive and when it’s all right to leave it as is. Below are a few guidelines to help you decide whether or not to split your infinitives (infinitive verb forms are underlined, adverbs are italicized).
SubsubsectionWhen to Split InfinitivesClear Split Infinitive: Backpacking Trip
Sometimes the sentence meaning is clearer when the adverb modifying the verb stays within the verb form. For instance, consider the sentences below:
“I like toclearlywrite sentences using infinitives.”
“Tofullyunderstand infinitives, one should learn when to use them.”
Both of these sentences have split infinitives (“to clearly write” and “to fully understand”). However, if we move the adverbs outside of the verb form, suddenly the sentences become less clear and more awkward:
“I like to write sentences clearly using infinitives.”
In this sentence, it is not clear whether “clearly” is modifying “to write” or “using infinitives”; does the person like to clearly write or clearly use infinitives? In this case, it might be better to leave the modifying adverb within the verb form.
“To understand infinitives fully, one should learn when to use them.”
In this sentence, the modifying adverb “fully” is placed outside of the verb form “to understand.” While this placement does not interfere with the meaning or fluency of the sentence, it breaks up the logical unit of thought; one must refer back to the intact verb form “to understand” in order to identify what “fully” is modifying. Therefore, it might be better to split the infinitive so the reader has a clearer idea of what kind of understanding the sentence is promising (full understanding).
Below are some more examples of infinitives that are probably okay to leave split:
Clear
“In order toproperlyplan for a backpacking trip, you must get all the right gear ahead of time.” [infinitive “to plan” is split]
Confusing
“In order properlyto plan for a backpacking trip, you must get all the right gear ahead of time.” [infinitive is intact, but sentence is just plain awkward]
“In order to plan for a backpacking trip properly, you must get all the right gear ahead of time.” [infinitive is intact and the sentence is acceptable, but the modifier “properly” is somewhat removed from the verb form “to plan”]
Example7.1.21.Clear Split Infinitive: Tea.
Clear
“By drinking more tea, I plan tograduallylessen my coffee dependence.” [infinitive “to lessen” is split]
Confusing
“By drinking more tea, I gradually plan to lessen my coffee dependence.” [infinitive intact, but modifier “gradually” could be referring to “plan” or “lessen”]
“By drinking more tea, I plan to lessengradually my coffee dependence.” [infinitive intact, but sentence is awkward]
“By drinking more tea, I plan to lessen my coffee dependence gradually.” [infinitive intact and sentence is acceptable, but modifier “gradually” is somewhat removed from the verb form “to lessen”]
Example7.1.22.Clear Split Infinitive: Social Justice on Campus.
Clear
“If you’d like toactivelyinvolve yourself in social justice opportunities on campus, you can visit the student diversity center” [infinitive “to involve” is split]
Confusing
“If you’d like activelyto involve yourself in social justice opportunities on campus, you can visit the student diversity center.” [infinitive intact, but sentence is awkward]
“If you’d like to involve yourself in social justice opportunities on campus actively, you can visit the student diversity center.” [infinitive intact, but modifier “actively” far removed from the verb form “to involve”]
Note7.1.23.
Though there are instances when it would be practical to split the infinitive, you need not always use an adverb. Cutting adverbs, especially when they result in split infinitives, often makes writing cleaner and more fluid.
SubsubsectionWhen not to Split Infinitives
While splitting the infinitive is sometimes necessary to preserve sentence fluency and thought coherency, it is usually better to avoid splitting them when you can. Infinitives are single units of thought, so keeping them intact often improves the reader’s understanding of the sentence. Additionally, splitting the infinitive can actually make the sentence more awkward. For instance, take the following sentences where the infinitives are intact:
“You should try to keep infinitives intact whenever possible.”
“I would like to write sentences with infinitives clearly and concisely.”
Both of these sentences keep the infinitive intact (“to keep” and “to write”). But say you tried to split the infinitives:
“You should try towhenever possiblekeep infinitives intact.”
In this sentence, inserting the modifier “whenever possible” between the verb form makes the sentence awkward and unwieldy. In this case, keeping the infinitive “to keep” intact makes the sentence more readable and clear.
“I would like toclearly and conciselywrite sentences with infinitives.”
Similarly, the infinitive verb form “to write” in this sentence is split by the modifying phrase “clearly and concisely.” In this case, splitting the infinitive with the modifier disrupts sentence fluency and expression of the verb form “to write”; therefore, it’s probably better to keep the infinitive phrase intact.
“Before the hiking trip, the group members had to check their gear carefully and thoroughly.” [infinitive intact]
Confusing
“Before the hiking trip, the group members had tocarefully and thoroughlycheck their gear.” [infinitive “to check” is split by the modifier “carefully and thoroughly,” which makes the sentence awkward]
Example7.1.25.Unclear Split Infinitive: Club Fair.
Clear
“The club fair is a great place to look for clubs and activities at your own pace.” [infinitive intact]
Confusing
“The club fair is a great place toat your own pacelook for clubs and activities.” [infinitive “to look” split by the modifier “at your own pace,” which makes the sentence awkward and unreadable]
