Two Formal Fallacies - Denying the Antecedent and Affirming the Consequent - Essay Example

It is an arrangement of reasoning that is permanently invalid or erroneous due in part to a mistake in the structure of the proposition that makes the argument wrong. For example: “If Gina owns a car, she is well-off. Gina is well-off. Therefore, Gina owns a car.” Informal fallacies are fallacious in that their premises are unable to support their conclusion but do not necessarily mean they are erroneous in logic. Denying the antecedent is a formal fallacy wherein its propositions do not provide strong bases to prove its conclusions despite the truth in its premise. For example, “If Ana is tall, then she is an athlete. Ana is not tall. Therefore, Ana is not an athlete.” The error occurs in the first premise because it disregards the function of “it” as a condition.

Another example would be, “If your headaches, then you got a migraine. My headaches; therefore, I have a migraine. This is particularly fallacious in that there are other reasons why the headaches, i.e. stress, cluster headache, tension headaches or may be caused by tumors. On the other hand, the proposition of affirming the consequent is all erroneous. Its conclusion is always invalid regardless of whether the first and second declarations are true. For example, “If people get into an accident, they are drunk. Paul got into an accident. Therefore, Paul was drunk.” The argument is wrong, although the statements are true because not all who get into accidents are caused by a drunk. In this instance, the premises are true but the argument is obviously false. Read More