Thanks to Geoffrey Pullum, who pointed me to this older Language Log article by Arnold Zwicky which discusses some of the history of the prescriptive rule regarding that vs. which in restrictive relative clauses. It outlines what he knows about the development and origin of this rule and discusses the more general mechanisms which bring such rules about and ensconce them in style manuals and English classes.
Posted by Alan Hogue at December 31, 2006 08:09 PM