is that the witness is lying, that would be wrong. But if his argument would be that the witness should not be trusted, that would not be a fallacy. Argument from commitment An ad hominem argument from commitment is a type of valid argument that employs, as a dialectical strategy, the exclusive utilization of the beliefs, convictions, and assumptions of those holding the position being argued against, i.e., arguments constructed on the basis of what other people hold to be true. This usage is generally only encountered in specialist philosophical usage or in pre-20th century usages. This type of argument is also known as the ex concessis argument (Latin for "from what has been conceded already"). Usage in debates Ad hominem fallacies are considered to be uncivil and do not help creating a constructive atmosphere for dialogue to flourish. An ad hominem attack is an attack on the character of the target who tends to feel the necessity to defend himself or herself from the accusation of being hypocritical. Walton has noted that it is so powerful of an argument that it is employed in many political debates. Since it is associated with negativity and dirty tricks, it has gained a bad fame, of being always fallacious. Author Eithan Orkibi, having studied the Israeli politics prior to elections, described two other forms of ad hominem attacks that are common during election periods. They both depend on the collective memory shared by both proponents and the audience. The first is the precedent ad hominem, according to which the previous history of someone means that they do not fit for the office. It goes like this: "My opponent was (allegedly) wrong in the past, therefore he is wrong now". The second one is a behavioral ad hominem: "my opponent was not decent in his arguments in the past, so he is not now either". These kinds of attacks are based on the inability of the audience to have a clear view of the amount of false statements by both parts of the debate. Criticism as a fallacy Walton has argued that ad hominem reasoning is not always fallacious, and that in some instances, questions of personal conduct, character, motives, etc., are legitimate and relevant to the issue, as when it directly involves hypocrisy, or actions contradicting the subject's words. The philosopher Charles Taylor has argued that ad hominem reasoning (discussing facts about