Patrick S. O'Donnell says: February 2, 2013 at 10:06 am Malcolm, I???m sorry you simply are ill-informed, an ad hominem is one of many informal fallacies in philosophy (in law, on the other hand, ad hominem arguments are often perfectly acceptable, as in adversarial criminal proceedings that characterize Anglian legal systems): on informal fallacies, see, for example the list provided by my late c