> Oh look. A Google poster. With an AOL address. *YAWN*
>
A Circumstantial ad Hominem is a fallacy in which one attempts to
attack a claim by asserting that the person making the claim is making
it simply out of self interest and or circumstances. In some cases,
this fallacy involves substituting an attack on a person's
circumstances (such as the person's religion, political affiliation,
ethnic background, etc.) instead of and in place of the truth or
falsity of the claim being made.
A Circumstantial ad Hominem is a fallacy because a person's interests
and circumstances have no bearing on the truth or falsity of the claim
being made. While a person's interests will provide them with motives
to support certain claims, the claims stand or fall on their own. It
is also the case that a person's circumstances (religion, political
affiliation, etc.) do not affect the truth or falsity of the claim.
This is made quite clear by the following example: "Bill claims that
1+1=2. But he is a Republican, so his claim is false."
http://www.nizkor.org/features/fallacies/circumstantial-ad-hominem.html
