Logicians speak of arguments in terms of validity and soundness. Yet even entirely valid, sound arguments don't always win the day. In fact, it may well be more the rule than the exception that sound reasoning alone fails to persuade others to change their minds.
I have claimed elsewhere that, in the end, the only accepted form of argument is, "Says me." I should have said that's the only verbal argument, because there is another argument, universally accepted as sound in itself and overthrowing all opposition, that requires no words.