Captain James T Kirk did it, George Bernard Shaw championed it and yet most of us were taught to never do it … what? To split infinitives, of course.
The infinitive is the basic form of the verb. In most languages, it is a single word, but in English, it is made up of two words: to + [verbal part]. For example:
To Be is etre in French, esse in Latin, sein in German, etc.
To split an infinitive is to put a word in between the “to” and the verbal part. It’s not a problem in those languages with one-word infinitives, but it is in English, and oh how we like to get worked up about it!
The most common forms of split infinitives are to add an adverb and to add a negative.
To quickly go
To not go
Adding more than one word is also possible, such as
To more than double
Most people over the age of 40 will have been taught to avoid split infinitives as an absolute. Like so many grammar rules, these days it’s a question of style. There is no imperative reason not to do it, but in the vast majority of cases it will look like better English not to, and as I’ve said before, if your writing might be judged by someone who cares and it matters to you what they think, go with the “rule”.
For the most part, it just feels more English to avoid a split infinitive. No native speaker would say “I wanted to just like that go and see him” or “To better than achieve his goals…” for example. But there are plenty of things we would and do say, and partly when writing speech or in the voice of a casual character, it would be perverse not to use constructions like “I wanted to never see him again” or “I had to quickly grab all my things” and, of course…