WRONG: Splitting infinitives is bad

To begin with, a few definitions. If you know this bit, skip to paragraph six.

As English teachers like to say, verbs are “doing” words, and an infinitive is the form a “doing word” takes when it isn’t being done by anything in particular. It's the verb in its unused form.

In English infinitives begin with "to", eg to run, to explode, to burble. They are always, therefore, made up of two words, which makes them infinitive phrases, not infinitives. This is important, and we'll get to why in a sec.

An adverb, meanwhile, shades the meaning of a verb (eg, run quickly, explode messily, burble charmingly). They typically, but not always, end in -ly. (Often and never are a couple that don't.)

The problem arises when putting infinitive phrases and adverbs together. Splitting an infinitive means putting an adverb between to and run, explode, burble, etc. Captain Kirk’s to boldly go is the most famous example (in the galaxy). The sticklers demand either boldly to go or to go boldly.

But what’s wrong with splitting infinitives? Nothing. The sticklers are wrong. As long as the split infinitive makes your meaning clearer or your sentence read more easily, you are innocent of any grammatical crime. Writers of Middle English happily used to split their infinitives (or used to happily split them, I should say), but the practice fell out of favour during the Renaissance (though Shakespeare still felt justified in using one). In later years it may have been that some grammar scholars, who based their prescriptive rules on those of Latin, felt that if a Latin infinitive couldn’t be split, being only one word (such as esse - to be), then neither should an English one. But as we've already seen, English doesn't have infinitives - it has infinitive phrases. So there. You can't split an infinitive, but you can split an infinitive phrase.

It is certainly the Latin-loving spoilsports we have to thank for the much-repeated (and completely wrong) belief that you can’t end a sentence with a preposition (eg with, to, from, by, over). The Right Reverend Robert Lowth, writing in 1762, declared it “an idiom which our language is strongly inclined to… but the placing of the preposition before the relative is more graceful as well as more perspicuous and agrees much better with the solemn and elevated style.” Well la-di-da, your Right Reverendship. Kingsley Amis, on the other hand, reckoned, “it is natural and harmless in English to use a preposition to end a sentence with.”

In either case, there are no rules of grammar, only traditions. Languages evolve with use, and the rules evolve with them. And the sticklers know the orifice up which their rules they can shove.