b) Verbal or Semi-logical In this form of fallacy, there is always a sentence of some sort of valid forms of argument but not exactly because of a word or words used in different senses. This is most observable in the fallacies of ambiguity. c) Material / informal Here whether valid or not the argument is fallacies because: i) The premises are false ii) Appeals are mainly to feelings iii) There is no structure of argument at all iv) Argument is not directed to the thesis in question.
3.2 Fallacies Involving Irrelevant Premises In logic, we have formal and informal fallacies. Within informal fallacies there are fallacies involving irrelevant premises, fallacies involving ambiguity and fallacies involving unwarranted assumptions. The difference between formal and informal fallacies is that, a formal fallacy always involves the explicit use of an invalid form which is not the case with informal fallacy. Fallacies involving irrelevant premises are kinds of informal fallacies that involve the use of premises that are logically irrelevant to their conclusions, but for psychological reasons, the premises appear relevant. The most common of such informal fallacies are as follows: (a) Argument against the person (Ad Hominem fallacy) The main business of this argument is to attack the person who advances an argument rather than providing a rational critique of the argument itself. The attacker’s main objective is to make it assertion acceptable, look at this for instance: · Mr. A: President Umaru Musa Yar’Adua of the Federal Territory of Nigeria will be the next African Union Chairman · Mr. B: Mr. Umaru Musa Yar’Adua is the president of one of the most corrupt countries in the world. Therefore it is impossible for him to become the future African union chairman. An argument against the person does not always involve outright verbal abuse. Subtle ways are sometimes used but with the sole aim of discrediting an opponent by suggesting that the opponent’s judgment is distorted by some factor in his or her circumstances. This form of argument is sometimes called the circumstantial ad hominem. For instance, during the celebration of their marriage, Mr. and Mrs. Kule refused to serve beer to their guests. They claimed that no born again child of God would either drink or serve beer to other persons. Here, you can see that Mr. and Mrs. Kunle commit the circumstantial form of the argument and hominem fallacy. You should always remember that the attack in the argument against the person can take three forms: i) Abusive ad hominem: direct personal attack on the opponent. ii) Circumstantial ad hominem: attempt to discredit by calling attention to the circumstances or situation of the opponent. iii) Tu quoque: charges the opponent with hypocrisy or inconsistency.