Originally Posted by Prestidigitweeze
I would suggest that varied use and substitution might suggest an inconsistency bred of vacillation, intended variety, remnants of earlier grammatical forms or mere carelessness. But then again, that is an unsubstantiated theory based on what is perhaps my persnickety need for organization which comes from years of formal training as a classical musician. In absolute music, syntax is always as pure as the composer chooses to make it.
I think varied use is just the nature of English as a language.
English is not included in the list
of languages with some central regulator.
Usage is ultimately the only definition.