Q: On your Grammar Myths page, you say the “to” in “to escape” is a preposition and not part of the infinitive. I think you’re wrong. Most linguists would say this “to” is most definitely not a preposition, but is actually part of the infinitive.
A: I disagree on two points.
(1) “To” is a preposition, even before an infinitive.
Ordinary dictionaries (The American Heritage Dictionary of the English Language, 4th ed., and Merriam-Webster’s Collegiate Dictionary, 11th ed.) classify the infinitival “to” as a preposition with the function of indicating that the following verb is an infinitive.
So do more scholarly sources, such as the Oxford English Dictionary, which notes that in modern English this prepositional sense has become weakened.
(2) When used before an infinitive, “to” is not part of the verb. Here I will quote The Cambridge Grammar of the English Language, written by two distinguished linguists, Rodney Huddleston and Geoffrey K. Pullum:
“Infinitival to is not part of the verb. The traditional practice for citation of verbs is to cite them with the infinitival marker to, as in ‘to be,’ ‘to take,’ and so on. That is an unsatisfactory convention, because the to is not part of the verb itself. It is not a (morphological) prefix but a quite separate (syntactic) word.” – CGEL, p. 84.
A great many other grammarians have said the same thing over the years.
And as I point out on the Grammar Myths page, the “to” isn’t always necessary. The word “escape,” for example, is an infinitive in both these sentences: (1) Blackbeard helped him to escape. (2) Blackbeard helped him escape.
The point I’m trying to make, of course, is that there’s nothing wrong with putting an adverb (like “discreetly”) between the prepositional marker “to” and a verb in this sentence: Dilbert decided to discreetly mention dating in the workplace.
In other words, the old “rule” against splitting an infinitive is bogus. If “to” isn’t part of the infinitive, there’s nothing to split.
(I discuss this in more detail in “Grammar Moses,” a chapter in my new book, Origins of the Specious: Myths and Misconceptions of the English Language, written with my husband, Stewart Kellerman.)