If you play Trivial Pursuit, you know about the grammatical error featured in the opening credits of Star Trek. The famous line “to boldly go where no man has gone before” contains the split infinitive “to boldly go” (where the adverb “boldly” splits the infinitive “to go”). While the line remains mostly unaltered throughout Star Trek’s many incarnations, it gets “corrected” in the first episode of the series Enterprise, in a recorded speech by warp drive inventor Zefram Cochrane: “To go boldly where no man has gone before.” Doesn’t have quite the same ring, does it?
The prescriptive rule against split infinitives was created in response to its growing usage in the 19th century. While no one was clearly identified as the creator of said rule, there were many writers who supported the edict. According to Bache (1869), "The to of the infinitive mood is inseparable from the verb.” Of like mind, Raub (1897) states, "The sign to must not be separated from the remaining part of the infinitive by an intervening word.” There were perhaps as many who denounced the restriction. But the rule took hold of public consciousness by the early 20th century, gaining a firm toe hold in academia and the media.
Trying to correct a split infinitive will sometimes cause problems. The aforementioned “to boldly go” converts well enough into “to go boldly.” The altered phrase might not have as much panache (if only because the original is so strikingly familiar), but it does carry the same meaning.
By contrast, consider the following (with the first line containing the split infinitive “to slowly remove” and the remaining lines as possible “solutions”):
1. “She decided to quickly remove all split infinitives from her writing.”
2. “She quickly decided to remove all split infinitives from her writing.”
3. “She decided to remove quickly all split infinitives from her writing.”
4. “She decided to remove all split infinitives quickly from her writing.”
5. “She decided to remove all split infinitives from her writing quickly.”
While the meaning is most often unaffected (e.g. making quick changes to the writing), line #2 instead describes a quick decision. Furthermore, line #s 3-5 come across as clunky.
Split infinitives might be against the rules, but sometimes they can’t be avoided. If you can find a way to omit them or rephrase them, by all means do so. But don’t alter them at the expense of meaning.
Consider this bit of sage advice from the Fowler brothers: "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" (The King’s English, 1907).
In closing, remember this overall approach to grammar:
Learn the rules. Understand the rules. Then decide when, how and why to break the rules to best effect.
NOTE: A tip of the virtual hat to Wikipedia for the quotes used above.