[bjhoops1]

Also, there is nothing illogical about saying "this person or source of information has a reputation for being wrong or deceitful, therefore I will not be spending my time examining their claims." This is not really an ad hominem, just saying that due to the unlikelihood of an individual having anything to contribute, you are choosing to not engage their argument. I suppose this falls under "running away from the argument".

[alexqgb]

Exactly. Which is why it would be an ad hominem (or really, ad feminum) to say "How can we possibly trust you as our CFO? You're a woman!" since there is no pertinent relationship between gender and the job's requirements. However, there's nothing illogical about saying "How can we possibly trust you as our CFO? You're a convicted embezzler!"

Indeed, if the personal considerations are this relevant, it would quite illogical not to consider them. Likewise, I someone has established a general reputation for idiocy, slop, and other crimes against lucidity, it's perfectly reasonable to flag their remarks as dubious until proven otherwise. It's actually a perfectly rational conservation of time and energy.

[JasonFruit]

Very true — it's not illogical to think that, or to use it as a reason to ignore the discussion. Responding to someone by pointing that reasoning out, however, is very seldom going to lead to productive discussion. It's usually best left unsaid.