I bet this post will send the grammar police into a collective tizzy. Why? Because I insist that there's no such thing as a split infinitive. (For those who don't know their grammar, the infinitive is the uninflected present form of a verb that is used like a noun.)

Now how did I come to that conclusion? Simple: I learned (some) German and French. Let's take the word "do": tun in German and faire in French, both forms you'll find in the dictionary. Note that these both have their infinitive endings; their stems are tu- and fai- respectively. Now, English lost its infinitive ending by the end of the Middle Ages under Scandinavian influence (the Old English word was dón).

But then along came Bishop Lowth, who in 1762 used Latin grammar to fix the rules of Classical English in his canonical grammar book. It was about that time that someone (was it Lowth? if anyone knows who did it, tell me in a comment) got the idea that the English infinitive must include the word "to". Excuse me, but "to" is just a preposition. And guess what? In German and French, it's used with the infinitive: zu tun in German, à faire in French. Not nearly as often as in English, but still they use it. But German also uses the infinitive form with auxiliary verbs: for example, ich will tun corresponding to "I will do".

So I concluded that the dictionary form of an English verb (e.g., do) is the infinitive, exactly as in German and French. The infinitive, properly speaking, is that form of the English verb used with auxiliary verbs (such as "will" and "may", but not "have") and the preposition "to". So a phrase like "to boldly go" may violate the rigid rules of Classical English, in which putting an adverb between "to" and the verb is flagged as a violation called the "split infinitive". However, it's perfectly legal in the actual grammar of English. You see, in English there's no such thing as a split infinitive. If you want split infinitives, try German with its separable verbs.