Anna Schwartz is the author of a book review that came out in this month's (June 2009) Journal of Economic Literature on a recent biography of the economist and Nobel Laureate, Milton Friedman. One of her criticisms of the new Friedman biography is that the author missed one of the most important aspects of Friedman's personality--his style as an economic debater. She says,
For example, Friedman's style as a debater reveals an aspect of his personality. He was always courteous to his opponents in a debate, never attacked ad hominem. He concentrated on weaknesses of the opponent's arguments and invariably emerged as the victor in the debate.In addition to being a fallacious logical argument, ad hominem attacks are an indicator of the weakness of an argument. Ad hominem attacks reveal that the proponent either (1) does not understand the subject enough to make a sound argument, (2) is advocating a position that cannot be justified by logical reason, or (3) is simply using the debate as a platform to slander his opponent. Reasons (1) and (2) have relevance for judging the validity of the argument, but reason (3) is irrelevant.