Denying the Antecedent: Its Effective Use in Argumentation MARK STONE Department of Philosophy Furman University Greenville, SC 29613 mark.stone@furman.edu Abstract: Denying the antecedent is an invalid form of reasoning that is typically identified and frowned upon as a formal fallacy. Antecedent: Consequent: Affirming the Antecedent (correct) If A. Not necessarily. In some cases the argument must be rewritten using double negation or commutativity before it has a renamed form. Affirming the consequent—invalid. Denying the antecedent—invalid. Denying the antecedent isn’t always easy to spot. Even if both premises are true, the syllogism may still be invalid. 23 The argument form denying the antecedent is… INVALID 24 An argument with this form—“If p, then q. So, replacing words with letters and rearranging the statement can help simplify it. The words we use in an argument can sometimes hide the structure of the argument. If I work at Victoria's Secret: Then B. I must be sixteen or older. In this example, a valid conclusion would be: ~P or Q. This pattern is the fallacy called "denying the antecedent." Valid in logic means that if the premises happened to be true, then the conclusion must also be true. Determine whether the following argument is valid or invalid by identifying the form of each. Conclusion: Therefore, squirrels are fire-breathing creatures. So, are all valid arguments safe to believe? Since it is not a valid form of argument, it cannot prove that the position is false. Informally, this means that arguments of this form do not give good reason to establish their conclusions, even if their premises are true. Modus tollens—valid. Denying the antecedent makes the mistake of assuming that if the antecedent is denied, then the consequent must also be denied. So, this argument is invalid, involving a fallacy called denying the antecedent. Denying the antecedent is an invalid form of reasoning that is typically identified and frowned upon as a formal fallacy. Modus ponens—valid. Invalid. Not all cases of denying the antecedent will be this clearly wrong. Fallacy Fallacy of Denying the Antecedent The minor premise denies the consequent (then) from the major premise Since Marvell committed this fallacy purposefully, the form of syllogism is not flawed and the conclusion is valid Logic how received …show more content… Therefore, he is not a great scientist”—is an example of… For example, Premise 1: All mammals are fire-breathing creatures. Arguments of this form are invalid. A. I work at Victoria's Secret: Einstein did not invent the steam engine. Denying the antecedent is an invalid form of reasoning that is typically identified and frowned upon as a formal fallacy. Affirming the Consequent, Denying the Antecedent. By the counter example above, we have shown that the pattern you refer to as (2) can have a false conclusion with true premises. But they all make the same invalid move, ignoring the relationship between the “X” and “Y” conditions to imply that negating “X” also implies negating “Y.” As in the example above, though, this does not necessarily work from a … If q, then r. Therefore, if p, then r”—is known as… HYPOTHETICAL SYLLOGISM 25 This argument—“If Einstein invented the steam engine, then he's a great scientist. http://www.criticalthinkeracademy.com This video introduces the formal fallacy known as "denying the antecedent". Contrary to arguments that it does not or at least should not occur, denying the antecedent is a legitimate and effective strategy for undermining a position. Premise 2: Squirrels are mammals. Contrary to arguments that it does not or at least Simplify it this pattern is the fallacy called denying the antecedent is an invalid form of each called the! 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