ad Hominem

Taxonomy: Logical Fallacy > Informal Fallacy > Red Herring > Genetic Fallacy

Translation: "Argument against the man" (Latin)

Alias: The Fallacy of Personal Attack


William Bennett…, leader… of the antirap campaign…, [has] had no trouble finding antipolice and antiwomen lyrics to quote in support of [his] claim that "nothing less is at stake than civilization" if rappers are not rendered silent. So odious are the lyrics, that rarely do politicians or journalists stop to ask what qualifies Bennett to lead a moralistic crusade on behalf of America's minority youth. Not only has he opposed funding for the nation's leader in quality children's programming (the Public Broadcasting Corporation), he has urged that "illegitimate" babies be taken from their mothers and put in orphanages.

Source: Barry Glassner, The Culture of Fear (1999), p. 122.


Vitruvian man


A debater commits the Ad Hominem Fallacy when he introduces irrelevant personal premisses about his opponent. Such red herrings may successfully distract the opponent or the audience from the topic of the debate.


Ad Hominem is the most familiar of informal fallacies, and—with the possible exception of Undistributed Middle—the most familiar logical fallacy of them all. It is also one of the most used and abused of fallacies, and both justified and unjustified accusations of Ad Hominem abound in any debate. It is a frequently misidentified fallacy, for many people seem to think that any personal criticism, attack, or insult counts as an ad hominem fallacy. Moreover, in some contexts the phrase "ad hominem" may refer to an ethical lapse, rather than a logical mistake, as it may be a violation of debate etiquette to engage in personalities. So, in addition to ignorance, there is also the possibility of equivocation on the meaning of "ad hominem".

For instance, the charge of "ad hominem" is often raised during American political campaigns, but is seldom logically warranted. We vote for, elect, and are governed by politicians, not platforms; in fact, political platforms are primarily symbolic and seldom enacted. So, personal criticisms are logically relevant to deciding who to vote for. Of course, such criticisms may be logically relevant but factually mistaken, or wrong in some other non-logical way.

Finally, the phrase "ad hominem argument" is occasionally used to refer to a very different type of argument, namely, one that uses premisses accepted by the opposition to argue for a position. In other words, if you are trying to convince someone of something, using premisses that the person accepts—whether or not you believe them yourself. This is not necessarily a fallacious argument, and is often rhetorically effective.


  • Abusive: An Abusive Ad Hominem occurs when an attack on the character or other irrelevant personal qualities of the opposition—such as appearance—is offered as evidence against their position. Such attacks are often effective distractions ("red herrings"), because the opponents feel it necessary to defend themselves, thus being distracted from the topic of the debate.
  • Circumstantial: A Circumstantial Ad Hominem is one in which some irrelevant personal circumstance surrounding the opposition is offered as evidence against their position. This fallacy is often introduced by phrases such as: "Of course, that's what you'd expect them to say." The fallacy claims that the only reason why they argue as they do is because of personal circumstances, such as standing to gain from the argument's acceptance.

    This form of the fallacy needs to be distinguished from criticisms directed at testimony, which are not fallacious, since pointing out that someone stands to gain from testifying a certain way would tend to cast doubt upon that testimony. For instance, when a celebrity endorses a product, it is usually in return for money, which lowers the evidentiary value of such an endorsement—often to nothing! In contrast, the fact that an arguer may gain in some way from an argument's acceptance does not affect the evidentiary value of the argument, for arguments can and do stand or fall on their own merits.

  • Poisoning the Well
  • Tu Quoque


  • Q: Despite taking an introduction to logic course last semester, I still cannot differentiate between when it's permissible to attack someone's credibility and when it's considered an ad hominem. Could you shed some light on this for me?―Paul Margiotis

    A: The main thing to keep in mind is the distinction between argumentation and testimony. The whole point of logic is to develop techniques for evaluating the cogency of arguments independently of the arguer's identity. So, ask the question: is the person being criticized arguing or testifying? Are reasons being presented, or must we take the person's word for something? If the person is arguing, the argument should be evaluated on its own merits; if testifying, then credibility is important.

  • Q: I am having a disagreement over the proper usage of the term "ad hominem". My opponent claims that any personal attack during a debate that is not an attempt to discredit the opponent, but just rude, is an "ad hominem attack", if not necessarily an "ad hominem argument". I believe this is a false distinction, partially due to a misreading of your paragraph on misidentification of ad hominem arguments. I argue that the personal insult is not an ad hominem because it is not an attempt to discredit the argument of the opponent, but is just rudeness. Can you please help?―Jon

    A: I don't think there's a precise definition of "ad hominem attack", but on the rare occasions when I've used the phrase it was as a synonym of "personal attack". So, an ad hominem attack is not necessarily an argument, let alone an instance of the fallacy. A lawyer attacking the credibility of a witness in a trial would be engaging in an "ad hominem attack", but not necessarily a fallacious one. However, every ad hominem argument is an ad hominem attack. Thus, ad hominem attack is a more general concept than ad hominem argument.

Analysis of the Example:

This is an Ad Hominem of the circumstantial variety. Glassner suggests that Bennett is somehow unqualified to criticize rap music because of positions he allegedly took on other issues. However wrong Bennett may have been on other issues, such as the funding of public television or illegitimacy, that does not mean that his criticisms of rap were mistaken.


S. Morris Engel, With Good Reason: An Introduction to Informal Fallacies (Fifth Edition) (St. Martin's, 1994), pp. 198-206.


  • Alan Brinton, "The Ad Hominem" in Fallacies: Classical and Contemporary Readings, edited by Hans V. Hanson and Robert C. Pinto (Penn State Press, 1995), pp. 213-222
  • Frans H. Van Eemeren & Rob Grootendoorst, "Argumentum Ad Hominem: A Pragma-Dialectical Case in Point" in Fallacies: Classical and Contemporary Readings, edited by Hans V. Hanson & Robert C. Pinto (Penn State Press, 1995), pp. 223-228.
  • Yvonne Raley, "Character Attacks: How to Properly Apply the Ad Hominem", Scientific American, 5/2008
  • Douglas N. Walton, Arguer's Position: A Pragmatic Study of Ad Hominem Attack, Criticism, Refutation, and Fallacy (Greenwood, 1985).