> Ad Hominem

Def.: Any attempt to discredit a view by calling attention to the character, actions or personal circumstances of those who hold it rather than the reasoning they provide in support of it.

"Ad hominem" is Latin for "against the person." Anything that involves an attack on a person's character we call an Abusive Ad Hominem. Anything that appeals to a person's unique circumstances we call a Circumstantial ad Hominem. These are both fallacious for the simple reason that the personal character and circumstances of the individual reasoner are logically irrelevant to the question whether the reasoning itself is any good.

http://www.csus.edu/indiv/g/gaskilld/criticalthinking/Six%20...