That’s the odd part. It’s been a century (at least) since any leading grammarian has endorsed the preposition rule, or the split infinite one, for that matter.
Fowler’s Modern English Usage, first published in 1926, has pages of small print on the two subjects. He doesn’t excerpt well, but he calls the preposition rule to be once a “cherished superstition.” He also cites Dryden as being a monomaniac on the subject, but counters him with about 20 equally famous writers who didn’t care. He’s not much kinder on split infinitives.
So why did teachers keep on teaching this nonsense for decades? (The New York Times Copyeditor Theodore Bernstein gave one of his books on usage the wonderful title of Miss Thistlebottom’s Hobgoblins.) I can understand teaching beginners rules instead of nuances, but these were never rules and their application often results in more contorted English rather than better English.
Colibri’s link makes the analogy to German, where indeed “prepositions” that are part of the meaning of the verb must be placed at the end of sentence. For example, the verb “ausgehen” means “to go out” (aus=out, gehen=to go). Conjugated, it would appear as (for example) “ich gehe aus” - and you can put any number of objects and adverbs between “gehe” and “aus.”
Of course, the analogy between English and German word order only goes so far… thank goodness! (It gets a lot more complicated.)
Amen. This posting explains the basics of all the strange rules of English grammar, to wit: Latin was welded on in the days when English was just starting to take off as a “literary” language. Remember that, until the early 1700s, all writers of what we would call “literature” (science, law, philosophy, religion, and history) wrote in Latin. Only a few daring experimenters (Dante, Milton, Cervantes, Chaucer) used the language of the “streets”, and perhaps more for the sake of art than for clarity.
Unfortunately, the strange stew of “French” and “German” that makes up English is not at all suited to Latin constructions. Fortunately, as a technical writer I have learned that clarity rules grammar, and not the other way around. If someone gives you the razz for minor faults of grammar, dismiss him or her as a poor soul whose erudition has defeated his or her wisdom.
“When the literary German dives into a sentence, that’s the last you see of him until he emerges from the other side of the Atlantic with his verb in his mouth.”
Mark Twain. One of my favorites of his quotes. from A Connecticut Yankee in King Arthur’s Court, of all places, although he expressed similar sentiments elsewhere.