Translated from Latin to English, “Ad Hominem” means “against the man” or “against the person.”
An Ad Hominem is a general category of fallacies in which a claim or argument is rejected on the basis of some irrelevant fact about the author of or the person presenting the claim or argument. Typically, this fallacy involves two steps. First, an attack against the character of person making the claim, her circumstances, or her actions is made (or the character, circumstances, or actions of the person reporting the claim). Second, this attack is taken to be evidence against the claim or argument the person in question is making (or presenting). This type of “argument” has the following form:
1. Person A makes claim X.
2. Person B makes an attack on person A.
3. Therefore A’s claim is false.
Ad hominem is usually used to distract from the message, so it’s fallacious when the message is of greater importance than the messenger’s character. However, we evaluate the credibility of the messenger all the time.
Ad hominem is heuristic in which the message is ignored to some degree in favor of impugning the credibility of the messenger. Or, perhaps more simply: we evaluate the messenger’s credibility when evaluating the message. It is heuristic because it is a short cut but like all shortcuts, it can go horribly wrong.
It is Ad hominem fallacy to impugn the moral character of Julian Assange to avoid his message re the freedom of press. The ad hominem fallacy or argument ad hominem will not in any manners or shape affect the secrets that are revealed in the cables. The cables remain separate from the message and from the messenger. The cables stand alone. The content of the cables in itself has no relation to the credibility of the one who has released the cables. The cables are not messages. The cables are facts delivered by a stateless internet media outlet. The cables are news.