Deductive and inductive reasoning is used to evaluate whether an argument is valid or not (Bavelas, Black, Chovil & Mullett, 1990). However, sound logic is required for any argument to reach valid conclusions. When evaluating or making a philosophical argument, different logical errors/logical fallacies are used. These logical fallacies may include mere assertion, ad hominem, pseudo-questions, false cause, sweeping generalizations, red herring, equivocation or changing meanings and slippery slope (Tait, 2009).
An argument based on mere assertion is based on one’s belief (Tait, 2009). The validity of any statement in this case must be supported by deductive or inductive meanings to make sense to the believer. One may for instance argue that the President did not misuse funds because he cannot do that. This argument may remain unsound until evidence and facts are supplied to support the claim.
In an argument pegged on circular reasoning, the conclusion and the premise are believed to be same (Mercier & Sperber, 2011). For instance, although there is no evidence which has been used to prove about the authorship of the Bible, people argue that it is true because it was written by God. Consequently, when one says that the Bible was written by God, the statement also means that it is true.
Ad hominem arguments scrutinize motives or reasons that may have made a person advance an argument or form a belief (Klement, 2002). It is mostly used by politicians to attack their opponents with words that are irrelevant to the argument (Mercier & Sperber, 2011). For instance, someone may argue that a security policy proposed by Mr X should not be adopted because Mr. X is adulterous. This argument may be seen as quite irrelevant since adultery is not related in any way to government security.
Similarly, red herring brings out a claim which is not relevant to the argument. Just like ad hominem, red herring is used to distract or confuse the audience and the opponent (Klement, 2002). For instance, a young man may be fighting with his girl friend about who should make the bed but the man points out that he bought made the breakfast. Although this may be true, it is not in any way related to the question of who should make the bed.
Although pseudo questions appear as making some sense, they derive no answers because the questions themselves are usually nonsensical (Carothers, 2007). Pseudo questions have often been asked in relation to God’s power and might. One may for instance ask, “If God is in deed all powerful and mighty, could he make a mountain that is so wide that he could not himself see the other end?” As far as philosophers are concerned, such arguments may be considered as word games which create nonsensical contradictions.
A false cause on the other hand is based on relational causes. This fallacy occurs when one assumes that if an event happens after an earlier event, the first event must have caused or initiated the second occurrence (Carothers, 2007). In this case, if G happened after F, F must have caused G. Although the result might be true, it may have as well happened as a mere coincidence and not out of causal relationship. A young boy may for instance argue that every time he eats fish some minutes before sitting for a test, he gets an A in the test. Therefore, if he will not eat fish before sitting for the next test, he will not pass.
In relation to other fallacies, sweeping generalizations fallacy is considered as a conclusion that is attained by considering several specific instances while assuming that they all apply to all scenarios (Walton, 1990). For instance, one may have met only two Jamaicans in his life who happened to be extremely short. Such a person may falsely conclude that all Jamaicans are extremely short. Such a conclusion can be disputed by a wide range of evidence.
Slippery slope arguments introduce various causal variables. One may for instance argue that if D happens, E will also happen. This follows that F, G and H will also happen. This fallacy is unreliable because of the many steps of causation and variables involved (Mercier & Sperber, 2011). If for instance J says that tea cannot be grown in Georgia, it follows that tea will not be grown anywhere else and all those who depend on tea will go without a beverage since they will never have tea.
As a philosophical fallacy, equivocation or changing meanings as an error occurs when intended meaning changes in the middle of an argument. In this case, it is important for the person making the argument to be open to refutation and admit the argument was wrong if convincing evidence is presented by an opposing side (Walton, 1990). Considering that some decisions may lead to poor decisions and distortions, the functions of reasoning should be done with much re-thought (Mercier & Sperber, 2011).
References
Bavelas, J., Black, A., Chovil, N. & Mullett, J (1990). Truths, Lies and Equivocations. The Effects of Conflicting Goals on Discourse. Journal of Language and Social Psychology, 9, 135-161.
Carothers, T. (2007). The Sequencing Fallacy. Journal of Democracy, 18(1), 12-27.
Klement, K. (2002). When Is Genetic Reasoning not Fallacious? Netherlands: Kluwer Academic Publishers.
Mercier, H. & Sperber, D. (2011). Why Do Humans Reason? Arguments for an Argumentative Theory. Behavioral and Brain Sciences, 34, 57-111.
Tait, G. (2009). The Logic of ADHD: A Brief Review of Fallacious Reasoning. Studies in Philosophy and Education, 28(3), 239-254.
Walton, D. (1990). Ignoring Qualifications (Secundum Quid) As a Sub-Fallacy of Hasty Generalization. Logique & Analyse, 129, 113-154.