Anderson: Taking the long view, history shows that word usage and grammar rules are constantly changing and evolving-sometimes resulting in entirely new languages  Since they will change regardless of our efforts, we shouldn' t worry about violations of grammar rules  Lipton: That' s like arguing that we shouldn' t worry about enforcing laws since, in the larger scheme of things, laws change and nations come and go
But of course it is good that laws are enforced
languages evolve through an accumulation of changes in usage and rules