Ad hominem is an argument that appeals to personal properties of an opponent instead of being based on objective facts and reasoning. The term was introduced by the roman rhetoricians in order to classify methods of persuasion appealing to emotions and prejudices of listeners. This method was not considered prohibited neither in ancient nor in modern oratory practices. Though, the use of it is improper in scientific or professional discussion since the final point of such discussion is the truth, but not a winning position in the eyes of the audience.
There are three kinds of the ad hominem argument: ad personam (personal attacks based on harsh critique and insults of opponent), ad hominem circumstantiae (appealing to personal circumstances of the opponent while opposing his argument), and ad hominem tu quoque (pointing out that the opponent is acting contrary to his own argument).
Ad hominem argument is the opposite of ad rem argumentation, the objection of which is to reasonably prove one’s position instead of outarguing certain opponents.
Ad hominem relates to so called logical tricks and is psychologically effective, though logically improper way of proving one’s position. The form of the argument is:
- Person A makes a statement.
- An unacceptable fact is known about this person.
- Therefore, the statement is wrong.
Fallaciousness of such argumentation is obvious: negative characterization of a man does not necessarily affect his statement’s validity.
Ad personam often presumes insults and disparagement of the opponent. Generally, it points out the facts characterizing the opponent, usually without relation to his argumentation. The main purpose of it is to create a negative image of the opponent, thus make his statements look unreliable. This kind of argumentation proves to be effective because of so called Halo effect, which lays in the impact of general opinion about a man on the perception of his particular qualities.
Ad hominem circumstantiae denotes personal circumstances of individual and presumes preconception of the opponent as a reason to denounce his statements. This kind of argumentation is also logically invalid and is not considered proper in the majority of cases.
Ad hominem tu quoque points out the opponent’s imperfection when facing the critique and presumes the inconsistency of the opponent.
Nevertheless, in some cases the ad hominem argument might be considered legitimate. While this kind of argumentation is a personal attack, it may be appropriate when personality of the opponent is relevant to a discussion. For instance, when a position of an individual is contradictory to the facts of his biography and his actions. Thus, it challenges the individual to explain his inconsistency. The circumstantial ad hominem, on the other hand, in some cases might point out the self-interest of the opponent in relation to his position, thus raise reasonable suspicion to his arguments. When one’s interests or engagements appear to have an impact on a position one is trying to prove, it is fair to have doubts about individual’s objectivity and point out these matters in a discussion. For example, the representatives of tobacco companies claiming that smoking of cigarettes is harmless might be considered to protect their financial interests. Thus, the doubt in their statements is reasonable since they are most likely based on self-interest. Also, for instance, in some cases, one’s arguments about the aspects of drug use might be fairly found to be based on a fact that he is a drug addict himself.
Anyway, resorting to these methods of argumentation is inappropriate in most cases and is considered an instrument of a demagogue. One should base his statements on logical reasoning and appeal to facts relevant to the subject of discussion, the point of which is the objective truth but not a delight of an audience.