Prescriptive Grammar Rules
/Most of the hobgoblins of a contemporary prescriptive grammar (don’t split infinitives, don’t end a sentence with a preposition) can be traced back to eighteenth-century fads.
Of course, forcing modern speakers of English to not – whoops, not to split an infinitive because it isn’t done in Latin makes about as much sense as forcing modern residents of England to wear laurels and togas.
But once introduced, a prescriptive rule is very heard to eradicate, no matter how ridiculous. Inside the educational and writing establishments, the rules survive by the same dynamic that perpetuates ritual genital mutilations and college fraternity hazing: I had to go through it and am none the worse, so why should you have it any easier? Anyone daring to overturn a rule by example must always worry that readers will think he or she is ignorant of the rule, rather than challenging it.
Since perspective rules are so psychologically unnatural that only those with access to the right schooling can abide by them, they serve as shibboleths, differentiating the elite from the rabble.
Steven Pinker, The Language Instinct