Space, the final frontier. These are the voyages of the Starship Enterprise. Its five-year mission: to explore strange new worlds, to seek out new life and new civilisations, to boldly go where no man has gone before.
Oh dear, oh dear, oh dear. What were teachers of English grammar to do in the face of such a pervasive example of a common howler – the split infinitive.
It would be correct to say ‘boldly to go where no man has gone before’ or ‘to go boldly where no man has gone before’.
But this is where the people have beaten the grammarians, at least in daily speech. I think this is partly an example of popular revolt against the rules of grammar. Winston Churchill had his proof corrected to move the prepositions from the end of the sentence (which is grammatically incorrect) to the middle. He retorted ‘This is the sort of nonsense up with which I will not put’. As he was who he was, and the publishers did not want to lose their lucrative author, he won the day.
In the case of ‘to boldly go’, I think it’s simply a case of euphony: it just sounds better.