Philosophy

Philosophy Study Guide

1.9 Evaluating Arguments Evaluating arguments involves determining if the argument is valid or invalid and if the argument is sound or unsound; further, it investigates the truth of the reason and the validity of the conclusion. When assessing the truth of an argument, the process involves assessing how true are the supporting reasons that are being used to support a conclusion which involves a complex and ongoing process. Another step in evaluating an argument includes determining if an argument is sound, which looks at assessing if the argument passes the test of both truth and validity. When an argument has a valid structure and truthful reasoning then the argument is said to be sound. When an argument has either false reasons or an invalid structure, it is considered to be unsound. Assessing validity involves investigating the relationship between the reasons and the conclusions. Evaluation of arguments involves four different types if arguments forms which include: ● Valid argument: Reasons support the conclusion so that the conclusion follows from the reasons offered. ● Deductive argument: Conclusions follow necessarily from the reasons a person accepts the supporting reason as true; they then accept the conclusion as true (syllogism, modus ponens, modus tollens, and disjunctive syllogism). ● Invalid argument: The reasons do not support the conclusions. Since the premises are invalid we cannot ascertain the validity of the conclusion. ● Inductive argument: A type of argument that states the conclusion contains a probable truth based on the strength of the premises provided. Inductive arguments work under the assumption that the premises are so logically sound that the likelihood of the conclusion proving false is almost negligent. 1.10 Informal Fallacies An informal fallacy is an argument whose stated premises may fail to adequately support its proposed conclusion. The problem with an informal fallacy is that it often stems from reasoning that renders the conclusion unpersuasive. In contrast to a formal fallacy of deduction, the error is not a flaw in logic. Unsound arguments are often persuasive because they usually appeal to our emotions and prejudices and often support conclusions that we want to believe are accurate. Three different types of fallacies include: fallacies of false generalization, casual fallacies, and fallacies of relevance. ● Fallacies of false generalization: Group of fallacies arises from errors in reaching a general conclusion. Attributes obtained from an individual are then applied to the entire group which that individual comes from. There are 3 main ways this occurs: o Hasty generalization: Occurs when people try to reach a general conclusion too quickly, lacking a sufficient number of instances in the sample population to legitimately justify generalization to the target population. o Sweeping generalization: Involves the failure to take into account exceptions to the rule, thereby “sweeping” the exceptions into a larger group. o False dilemma: Also known as the either/or fallacy or the black or white fallacy. This occurs when we are asked to choose between two extreme alternatives without being able to consider additional options.

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