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Split infinitive

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A split infinitive or cleft infinitive is an English-language grammatical construction in which a word or phrase, usually an adverb or other adverbial, comes between the marker to and the bare infinitive (uninflected) form of a verb. One of the most famous split infinitives occurs in the opening sequence of the Star Trek television series: to boldly go where no man has gone before. Here, the adverb "boldly" splits the full infinitive "to go." More rarely, the term compound split infinitive is used to describe situations in which the infinitive is split by more than one word: The population is expected to more than double in the next ten years.

As the split infinitive became more popular in the 19th century, some grammatical authorities sought to introduce a prescriptive rule against it. The construction is still the subject of disagreement among native English speakers as to whether it is grammatically correct or good style. Henry Fowler wrote in 1926, "No other grammatical issue has so divided English speakers since the split infinitive was declared to be a solecism in the 19c: raise the subject of English usage in any conversation today and it is sure to be mentioned." However, most experts on language now agree that the split infinitive is sometimes appropriate. Those who use it consciously may see it as a form of hyperbaton, and some major poets have employed this to good effect.

History of the construction

Middle English

In Old English, most infinitives were single words ending in -an (compare modern German and Dutch -en), but about one quarter were "to" followed by a verbal noun in the dative case, which ended in -anne or -enne. In Middle English, the bare infinitive and the infinitive after "to" took on the same uninflected form. The "to" infinitive was not split in Old or Early Middle English. The first known example in English, in which a pronoun rather than an adverb splits the infinitive, is in Layamon's Brut (early 13th century):

and he cleopede him to; alle his wise cnihtes.
for to him reade;
And he called to him all his wise knights / to advise him.

This may be a poetic inversion for the sake of meter, and therefore says little about whether Layamon would have felt the construction to be syntactically natural. However, no such reservation applies to the following prose example from Wycliffe (14th century):

For this was gret unkyndenesse, to this manere treten there brother.
For this was great unkindness, to treat their brother in this manner.

Modern English

After its rise in Middle English, the construction became rare in the 15th and 16th centuries. William Shakespeare used only one, and it is a special case as it is clearly a syntactical inversion for the sake of rhyme:

Root pity in thy heart, that when it grows
Thy pity may deserve to pitied be (Sonnet 142).

Edmund Spenser, John Dryden, Alexander Pope, and the King James Version of the Bible used none, and they are very rare in the writing of Samuel Johnson. John Donne used them several times, though, and Samuel Pepys also used at least one. No reason for the near disappearance of the split infinitive is known; in particular, no prohibition is recorded.

Split infinitives reappeared in the 18th century and became more common in the 19th. Daniel Defoe, Benjamin Franklin, William Wordsworth, Abraham Lincoln, George Eliot, Henry James, and Willa Cather are among the writers who used them. Examples in the poems of Robert Burns attest its presence also in 18th century Scots:

Who dared to nobly stem tyrannic pride. ("The Cottar's Saturday Night")

However, it was especially in colloquial use that the construction experienced a veritable boom. Today, according to the American Heritage Book of English Usage, "people split infinitives all the time without giving it a thought".

Theories of origins

Although it is difficult to say why the construction developed in Middle English, or why it revived so powerfully in Modern English, a number of theories have been postulated.


Historical linguistics has speculated that its origins may lie in the context of the influence of Old French. The split infinitive appeared after the Norman Conquest, when English was borrowing widely from French. It is not found in other Germanic languages, except modern Swedish, which is an independent development; German still does not permit an adverb to fall between an infinitive and its particle (preposition). However, a construction which is parallel at least superficially can be found in French and other Romance languages. Compare modern German, French, and English:

Ich beschließe, etwas nicht zu tun.
I decide not to do something.
Je décide de ne pas faire quelque chose.
I decide to not do something.

Thus the English split infinitive ("I decide to not do something") may have arisen under the influence of French. However, grammarians of the Romance languages do not use the term "split infinitive" to describe the phenomenon, since the preposition is not considered a part of the infinitive form, and despite the surface-level similarity there are significant syntactical differences between the English and French constructions.


Traditional grammarians have suggested that the construction appeared because people frequently place adverbs before finite verbs. George Curme writes: "If the adverb should immediately precede the finite verb, we feel that it should immediately precede also the infinitive…") Thus if we say:

She gradually got rid of her teddy bears. or
She will gradually get rid of her teddy bears.

we may by analogy wish to say:

She wants to gradually get rid of her teddy bears.

This is supported by the fact that split infinitives are often used as echoes, as in the following exchange, where the riposte parodies the slightly odd collocation in the original sentence:

Child: I accidentally forgot to feed the hamster.
Parent: Well, you'll have to try harder not to "accidentally forget", won't you?

Here we can observe an adverb being transferred into split infinitive position from a parallel position in a different construction.

Transformational grammar

Transformational grammarians have attributed the construction to a re-analysis of the role of to.


In the modern language, splitting usually involves a single adverb coming between the verb and its marker. Very frequently, this is an emphatic adverb, for example:

I need you all to really pull your weight.
I'm gonna totally pulverise him.

Sometimes it is a negation, as in the self-referential joke:

Writers should learn to not split infinitives.

However, in modern colloquial English almost any adverb may be found in this syntactic position.

Compound split infinitives, splitting by more than one word, usually involve a pair of adverbs or a multi-word adverbial:

We are determined to completely and utterly eradicate the disease.
He is thought to almost never have made such a gesture before.
This is a great opportunity to once again communicate our basic message.

Examples of non-adverbial elements participating in the split-infinitive construction seem rarer in Modern English than in Middle English. The pronoun all commonly appears in this position:

It was their nature to all hurt one another.

and may even be combined with an adverb:

I need you to all really pull your weight.

This is an extension of the subject pronoun (you all). However an object pronoun as in the Layamon example would be unusual in modern English, perhaps because this might cause a listener to misunderstand the to as a preposition:

*And he called to him all his wise knights to him advise.

Other parts of speech would be very unusual in this position. However, in verse, poetic inversion for the sake of meter or of bringing a rhyme word to the end of a line often results in abnormal syntax, as with Shakespeare's split infinitive (to pitied be, cited above), in fact an inverted passive construction in which the infinitive is split by a past participle. Presumably, this would not have occurred in a prose text by the same author.

History of the term

It was not until the very end of the 19th century that terminology emerged to describe the construction. According to the main etymological dictionaries, the earliest use of the term split infinitive on record dates from 1897, with infinitive-splitting and infinitive-splitter following in 1926 and 1927 respectively. The now rare cleft infinitive is slightly older, attested from 1893. The term compound split infinitive is not found in these dictionaries and appears to be very recent.

This terminology implies analysing the full infinitive as a two-word infinitive, which not all grammarians accept. As one who used "infinitive" to mean the single-word verb, Otto Jespersen challenged the epithet: "'To' is no more an essential part of an infinitive than the definite article is an essential part of a nominative, and no one would think of calling 'the good man' a split nominative'." However, no alternative terminology has been proposed.

History of the controversy

Although it is sometimes reported that a prohibition on split infinitives goes back to Renaissance times, and frequently the 18th century scholar Robert Lowth is cited as the originator of the prescriptive rule, no such rule is to be found in Lowth's writing, nor in any other text prior to the mid-19th century.

Possibly the earliest comment against split infinitives was by an anonymous American in 1834:

I am not conscious, that any rule has been heretofore given in relation to this point […] The practice, however, of not separating the particle from its verb, is so general and uniform among good authors, and the exceptions are so rare, that the rule which I am about to propose will, I believe, prove to be as accurate as most rules, and may be found beneficial to inexperienced writers. It is this :—The particle, TO, which comes before the verb in the infinitive mode, must not be separated from it by the intervention of an adverb or any other word or phrase; but the adverb should immediately precede the particle, or immediately follow the verb.

In 1840, Richard Taylor also condemned split infinitives as a "disagreeable affectation". However, the issue seems not to have attracted wider public attention until Henry Alford addressed it in his Plea for the Queen's English in 1864:

But surely, this is a practice 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 already a choice between two forms of expression, 'scientifically to illustrate' and 'to illustrate scientifically,' there seems no good reason for flying in the face of common usage.

Others quickly followed, among them Bache, 1869 ("The to of the infinitive mood is inseparable from the verb"); William B. Hodgson, 1889; and Raub, 1897 ("The sign to must not be separated from the remaining part of the infinitive by an intervening word").

Even as these authorities were condemning the split infinitive, others were endorsing it: Brown, 1851 (lukewarmly: "The right to place an adverb sometimes between _to_ and its verb, should, I think, be conceded to the poets"); Hall, 1882; Onions, 1904; Jespersen, 1905; Fowler and Fowler (cited above). Despite the defence by some grammarians, by the beginning of the 20th century the prohibition was firmly established in the press and popular belief. In the 1907 edition of The King's English, the Fowler brothers 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."

In large parts of the school system, the construction was opposed with ruthless vigour. A correspondent to the BBC on a programme about English grammar in 1983 remarked:

"One reason why the older generation feel so strongly about English grammar is that we were severely punished if we didn't obey the rules! One split infinitive, one whack; two split infinitives, two whacks; and so on."

As a result, the debate took on a degree of passion which the bare facts of the matter never warranted. There was frequent skirmishing between the splitters and anti-splitters until the 1960s. George Bernard Shaw wrote letters to newspapers supporting writers who used the split infinitive, and Raymond Chandler complained to the editor of The Atlantic Monthly about a proofreader who changed Chandler's split infinitives:

"By the way, would you convey my compliments to the purist who reads your proofs and tell him or her that I write in a sort of broken-down patois which is something like the way a Swiss-waiter talks, and that when I split an infinitive, God damn it, I split it so it will remain split, and when I interrupt the velvety smoothness of my more or less literate syntax with a few sudden words of barroom vernacular, this is done with the eyes wide open and the mind relaxed and attentive. The method may not be perfect, but it is all I have."

Principal objections to the split infinitive

The descriptivist objection

Like most linguistic prescription, disapproval of the split infinitive was originally based on the descriptive observation that it was not in fact a feature of the prestige form of English which those proscribing it wished to champion. This is made explicit in the anonymous 1834 text, the first known statement of the position, and in Alford's objection in 1864, the first truly influential objection to the construction, both cited above. Still today, many English speakers avoid split infinitives not because they follow a prescriptive rule, but simply because it was not part of the language that they learned as children.

Many of those who avoid split infinitives differentiate according to type and register. Infinitives split by multi-word phrases ("compound split infinitives") and those split by pronouns are demonstrably less usual than the straightforward example of an infinitive split by an adverb. Likewise, split infinitives are far more common in speech than in, say, academic writing. Thus, while an outright rejection of the split infinitive is no longer sustainable on descriptive grounds (as it was in 1834), the advice to avoid it in formal settings, and to avoid some types in particular, remains a tenable position. The prescriptive rule of thumb draws on the descriptive observation that certain split infinitives are not usual in certain situations.

The argument from the full infinitive

A second argument is summed up by Alford's statement "It seems to me that we ever regard the to of the infinitive as inseparable from its verb."

The to in the infinitive construction, which is found throughout the Germanic languages, is originally a preposition before the dative of a verbal noun, but in the modern languages it is widely regarded as a particle which serves as a marker of the infinitive. In German, this marker (zu) precedes the infinitive, but is not regarded as part of it. In English, on the other hand, it is traditional to speak of the "bare infinitive" without to and the "full infinitive" with it, and to conceive of to as part of the full infinitive. Possibly this is because the absence of an inflected infinitive form made it useful to include the particle in the citation form of the verb, and in some nominal constructions where other Germanic languages would omit it (e.g. to know her is to love her). If we work with the concept of a two-word infinitive, this can reinforce an intuitive sense that the two words belong together. For instance, the usage writer John Opdycke argued that to go is "logically" one word because its closest French, German, and Latin translations are each one word.

However the two-part infinitive is disputed, and some linguists would say of English, too, that the infinitive is a single-word verb form, which may or may not be preceded by the particle to. Moreover, even if we accept the concept of the full infinitive, it does not necessarily follow that any two words that belong together grammatically need be adjacent to each other. They usually are, but counter-examples are easily found, such as an adverb splitting a two-word finite verb ("will not do", "has not done").

The argument from classical languages

Opdycke's mention of Latin above leads to a frequently discussed argument: that opposition to split infinitives in English is based on the impossibility of splitting them in Latin. Although it is not clear that this argument has ever been common among prescriptivists (with Richard Bailey, a professor of English, supposing arguments from other languages are "part of the folklore of linguistics"), many of those who accept split infinitives ascribe such an argument to their opponents. One example is in the American Heritage Book of English Usage: "The only rationale for condemning the construction is based on a false analogy with Latin." In more detail, the usage author Marilyn Moriarty states:

The rule forbidding a split infinitive comes from the time when Latin was the universal language of the world. All scholarly, respectable writing was done in Latin. Scientists and scholars even took Latin names to show that they were learned. In Latin, infinitives appear as a single word. The rule which prohibits splitting an infinite [sic] shows deference to Latin and to the time when the rules which governed Latin grammar were applied to other languages.

Thus the argument implies an adherence to the humanist idea of the greater purity of the classics, an idea which modern linguistics rejects. Those who state the argument are usually setting it up in order to knock it down. First, as the American Heritage Book of English Usage goes on to remark, "English is not Latin." Besides, as Latin has no marker, it does not model either solution to the question of where to place one: "there is no precedent in these languages for condemning the split infinitive because in Greek and Latin (and all the other romance languages) the infinitive is a single word that is impossible to sever." Thus if the argument ever was used, it is untenable.

In any case, Moriarty is clearly in error when she dates the prohibition to a time when Latin was regarded as the only scholarly language - this was not the case in 1834. As shown above, none of the prescriptivists who began the split-infinitive controversy mentioned Latin in this connection. Of the writers cited here (and the many others consulted) who ascribe the split-infinitive prohibition to Latinism, none cite a source, and as Bailey says, this ascription may be "folklore".

Current views

Present reference texts of usage deem simple split infinitives unobjectionable in many situations. For example, Curme's Grammar of the English Language (1931) says that not only is the split infinitive correct, but it "should be furthered rather than censured, for it makes for clearer expression". The Columbia Guide to Standard American English (1993) notes that the split infinitive "eliminates all possibility of ambiguity", in contrast to the "potential for confusion" in an unsplit construction. Merriam-Webster's Collegiate Dictionary says, "there has never been a rational basis for objecting to the split infinitive."

Nevertheless, many teachers of English still admonish students against using split infinitives in writing. Because the prohibition has become so widely known, the Columbia Guide (1993, above) recommends that writers "follow the conservative path [of avoiding split infinitives when they are not necessary], especially when you're uncertain of your readers' expectations and sensitivities in this matter." However, this is more a word of caution than a prohibition.

However, openness toward the construction usually has limits, and it would not be difficult to imagine examples which most people would regard as unnatural:

*I decided to by bus on Wednesday go.

Interestingly, Wycliff's Middle English compound split would, if transferred to modern English, be regarded by most people as unenglish:

*It was most unkind to in this manner treat their brother.

Attempts to define the boundaries of normality are controversial. In 1996 the usage panel of The American Heritage Book was evenly divided for and against such sentences as

I expect him to completely and utterly fail

but more than three-quarters of the panel rejected

We are seeking a plan to gradually, systematically, and economically relieve the burden.

Here the problem appears to be the breaking up of the verbal phrase to be seeking a plan to relieve: a segment of the head verbal phrase is so far removed from the remainder that the listener or reader must expend greater effort to understand the sentence. By contrast, 87 percent of the panel deemed acceptable the multi-word adverbial in

We expect our output to more than double in a year

not surprisingly perhaps, since here there is no other place to put the words more than without substantially recasting the sentence.

Splitting infinitives with negations remains an area of contention:

I want to not see you anymore.
I soon learned to not provoke her.

Even those who are generally tolerant of split infinitives may draw the line at these. This appears to be because the traditional idiom, placing the negation before the marker (I soon learned not to provoke her) or with verbs of desire, negating the finite verb (I don't want to see you anymore) remains easy and natural, and is still overwhelmingly the more common construction, even if some might argue that there are circumstances where it carries a slightly different meaning.

Avoiding split infinitives

Writers who avoid splitting infinitives either place the splitting element elsewhere in the sentence (as noted in the 1834 proscription) or reformulate the sentence, perhaps rephrasing it without an infinitive and thus avoiding the issue. Clearly, since many English speakers throughout history have not known the construction, or have known it only passively, there can be no situation in which it is a necessary part of natural speech. However, people who avoid it deliberately in obedience to prescribed rules may inadvertently produce an awkward or ambiguous sentence. Fowler (1926) stressed that, if a sentence is to be rewritten to remove a split infinitive, this must be done without compromising the language:

It is of no avail merely to fling oneself desperately out of temptation; one must so do it that no traces of the struggle remain; that is, sentences must be thoroughly remodelled instead of having a word lifted from its original place & dumped elsewhere:...

In some cases, moving the adverbial creates an ungrammatical sentence or changes the meaning. R.L. Trask uses this example:

  • She decided to gradually get rid of the teddy bears she had collected.
"Gradually" splits the infinitive "to get." However, if we were to move it, it could go:
  • She decided gradually to get rid of the teddy bears she had collected.
This might imply that the decision was gradual.
  • She decided to get rid of the teddy bears she had collected gradually.
This implies that the collecting process was gradual.
  • She decided to get gradually rid of the teddy bears she had collected.
This sounds awkward, as it splits the phrase "get rid of".
  • She decided to get rid gradually of the teddy bears she had collected.
This is almost as awkward as its immediate predecessor is.

The sentence can be rewritten to maintain its meaning, however, by using a noun or a different grammatical aspect of the verb, or by eschewing the informal "get rid":

  • She decided to get rid of her teddy bear collection gradually.
  • She decided she would gradually get rid of the teddy bears she had collected.
  • She decided to rid herself gradually of the teddy bears she had collected.

Fowler notes that the option of rewriting is always available but questions whether it is always worth the trouble.

Popular culture

  • The split infinitive, specifically its famous use in the Star Trek opening sequence, is the basis of a joke from Douglas Adams' The Hitchhiker's Guide to the Galaxy: "In those days men were real men, women were real women, small furry creatures from Alpha Centauri were real small furry creatures from Alpha Centauri. And all dared to brave unknown terrors, to do mighty deeds, to boldly split infinitives that no man had split before - and thus was the Empire forged."
  • Split infinitives are an annoyance of Inspector Fowler ( Rowan Atkinson), the main character of The Thin Blue Line-a British comedy series.
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