Argumentum ad hominem: the fallacy of attempting to refute a statement by attacking the person who makes the statement. Defense: the character or circumstances of the person making the statement has nothing to do with the truth or falsity of the statement per se.

The spurious Shakespeare/Julius Caesar quote above may not have been said by either of those to whom it has been attributed. However, how many "Caesars" in the history of the world could have truthfully made this statement had they been sufficiently eloquent?

Don Firth