Wednesday, May 19, 2010

Ad hominem

Ad hominem, also known as argumentum ad hominem (Latin: "argument toward the person" or "argument against the person") is an attempt to persuade which links the validity of a premise to a characteristic or belief of the person advocating the premise.  Formal arguments or debates demand adherence to formal logic.  Ad hominem is known as a classic logical fallacy, the fallacy of logic in this case being the personal attack part of the argument.  It is not a personal attack, gratuitous verbal abuse or "name-calling" by itself.  "You are just an ignorant twit" is verbally abusive, but it is not part of an argument so it cannot be ad hominem (or a classic logical fallacy of any kind).  "You are just an ignorant twit, so your evidence for creationism is hogwash" is an ad hominem attack.  Dan Barker in Godless: How an Evangelical Preacher Became One of America's Leading Atheists observes: "A strong clue that a person is arguing from a position of weakness is when they attack character rather than arguments and facts.  Bertrand Russell pointed out that ad hominem is a last ditch defense of the losing side."  Now you know.