Chapter 3 Logic - MPU 3193 PDF

CHAPTER 3 LOGIC MPU 3193 PHILOSOPHY AND CURRENT ISSUES What is Logic? Originated from the Greek word- logos- has a variety of meanings including word, thought, idea, argument, account, reason or principle In Arabic, the word ‘mantiq’ which means speech or words Logic is the scien...

CHAPTER 3 LOGIC MPU 3193 PHILOSOPHY AND CURRENT ISSUES What is Logic? Originated from the Greek word- logos- has a variety of meanings including word, thought, idea, argument, account, reason or principle In Arabic, the word ‘mantiq’ which means speech or words Logic is the science of correct reasoning.  It pertains to the study of rules and principles for making correct arguments. “Logic is a science that serves as a tool for the mind to reason out correctly.” Rules should be understood, not memorized. Understanding means being able to apply. Core of Logic The core of the science of logic lies in its collection of universal and eternal rules that ascertains truth in the flow of man’s statements. Logic is a discovery of the “norms” of correct thinking. Logic is primarily concerned with “arguments” Logic v. Psychology  Logic Psychology Studies the actual way the mind tells what the mind ought to do works, i.e. what the mind is. It is a normative science; it It is an empirical science; it studies imposes rules and norms for actual facts. thinking. Arguments Argument composed of premises and conclusion. Premise 1: All human will die Premise 2: I am a human Conclusion: I will die Arguments Argument is not equivalent to opinion Argument contains sequence of statements in which one of the statement is the conclusion. Proposition is a statement or assertion that expresses a judgement or opinion to determine statement is valid or invalid. If all premises are correct, the conclusion is also correct, then the argument is valid. Types of Argument Deductive Inductive Deductive Argument Refer to arguments that start with a more universal statement and conclude with a less universal statement. Example: Premise 1: All students need to attend class; (most universal) Premise 2: Melisa is a student; Conclusion: Therefore, Melisa need to attend class. (least universal) Inductive Argument Refers to arguments that start with a sufficient list of particular statements and end with a probable universal statement as inferred from the premises. Examples: Premise 1: All students will receive certificate during graduation day. Premise 2: Daud is a student Premise 3: Pauline is a student Premise 4: Shaline is a student Conclusion: Therefore, Daud, Pauline and Shaline probably will receive the certificates during graduation day. Deductive v. Inductive Deductive Reasoning Inductive Reasoning General Rule Specific Observation Lead down Lead into Specific Conclusion General Conclusion (always true) (may be true) Abductive Reasoning Abduction means determining the precondition. It is using the conclusion and the rule to assume that the precondition could explain the conclusion. Example: "When it rains, the grass gets wet. The grass is wet, it must have rained." Diagnosticians and detectives are commonly associated with this style of reasoning. FALLACIES Fallacies are common errors in reasoning that will undermine the logic of your argument. Fallacies can be either illegitimate arguments or irrelevant points, and are often identified because they lack evidence that supports their claim. Avoid these common fallacies in your own arguments and watch for them in the arguments of others. Slippery Slope This is a conclusion based on the premise that if A happens, then eventually through a series of small steps, through B, C,..., X, Y, Z will happen, too, basically equating A and Z. So, if we don't want Z to occur, A must not be allowed to occur either. Example: If we ban Myvi because they are bad for the environment eventually the government will ban all cars, so we should not ban Myvi. Hasty Generalization This is a conclusion based on insufficient or biased evidence. In other words, you are rushing to a conclusion before you have all the relevant facts. Example: Even though it's only the first day, I can tell this is going to be a boring course. In this example, the author is basing his evaluation of the entire course on only the first day, which is notoriously boring and full of housekeeping tasks for most courses. Post hoc ergo propter hoc This is a conclusion that assumes that if 'A' occurred after 'B' then 'B' must have caused 'A.’ Example: I drank bottled water and now I am sick, so the water must have made me sick. In this example, the author assumes that if one event chronologically follows another the first event must have caused the second. But the illness could have been caused by other things. Genetic Fallacy This conclusion is based on an argument that the origins of a person, idea, institute, or theory determine its character, nature, or worth. Example: The Volkswagen Beetle is an evil car because it was originally designed by Hitler's army. In this example the author is equating the character of a car with the character of the people who built the car. However, the two are not inherently related. Begging the Claim The conclusion that the writer should prove is validated within the claim. Example: Filthy and polluting coal should be banned. Arguing that coal pollutes the earth and thus should be banned would be logical. But the very conclusion that should be proved, that coal causes enough pollution to warrant banning its use, is already assumed in the claim by referring to it as "filthy and polluting." Circular Argument This restates the argument rather than actually proving it. Example: George Bush is a good communicator because he speaks effectively. In this example, the conclusion that Bush is a "good communicator" and the evidence used to prove it "he speaks effectively" are basically the same idea. Either/ Or This is a conclusion that oversimplifies the argument by reducing it to only two sides or choices. Example: We can either stop using cars or destroy the earth. In this example, the two choices are presented as the only options, yet the author ignores a range of choices in between such as developing cleaner technology, car-sharing systems for necessities and emergencies, or better community planning to discourage daily driving. Ad hominem This is an attack on the character of a person rather than his or her opinions or arguments. Example: Prime Minister’s strategies aren't effective because he is coming from low class community. In this example, the author doesn't even name particular strategies Prime Minister has suggested, much less evaluate those strategies on their merits. Instead, the author attacks the characters of the individuals. Ad populum/Bandwagon Appeal This is an appeal that presents what most people, or a group of people think, in order to persuade one to think the same way. Getting on the bandwagon is one such instance of an ad populum appeal. Example: If you were a true Malaysian, you would respect the choice of people to choose the current government. Stop criticizing the government. Red Herring This is a diversionary tactic that avoids the key issues, often by avoiding opposing arguments rather than addressing them. Example: The level of mercury in seafood may be unsafe, but what will fishers do to support their families? In this example, the author switches the discussion away from the safety of the food and talks instead about an economic issue, the livelihood of those catching fish. Straw Man This move oversimplifies an opponent's viewpoint and then attacks that hollow argument. Example: People who don't support the proposed state minimum wage increase hate the poor. In this example, the author attributes the worst possible motive to an opponent's position. In reality, however, the opposition probably has more complex and sympathetic arguments to support their point. By not addressing those arguments, the author is not treating the opposition with respect or refuting their position. Moral Equivalence This fallacy compares minor misdeeds with major atrocities, suggesting that both are equally immoral. Example: That parking attendant who gave me a ticket is as bad as Hitler. In this example, the author is comparing the relatively harmless actions of a person doing their job with the horrific actions of Hitler. This comparison is unfair and inaccurate.