Slide 1From Last TimeFrom Last Time…deductive reasoningHypothetical SyllogismCategorical SyllogismArgument by EliminationArgument Based on MathematicsArgument from DefinitionSummaryCOMMON PATTERNS OF INDUCTIVE REASONINGInductive GeneralizationPredictive ArgumentArgument from AuthorityCausal ArgumentArgument from AnalogyStatistical ArgumentIn conclusion…For Next Time…CRITICAL REASONINGWeek 4: Class 1FROM LAST TIME“Deductive arguments try to prove their conclusions with rigorous, inescapable logic. Inductive arguments try to show that their conclusions are plausible or likely given the premise(s).” (53)F R O M L A S T T I M E … D E D U C T I V E R E A S O N I N Ghypothetical syllogismcategorical syllogismargument by eliminationargument based on mathematicsargument from definitionHYPOT H E TICA L S Y L LO G ISMA three-lined argument that contains an if/then premiseFor Example:•If I want to get an A in Critical Reasoning, then I need to study for the Quiz on Friday. •I want to get an A in Critical Reasoning. •Therefore, I need to study for the Quiz on Friday.CATE G OR IC AL S YLLOGISM.. a three-line argument in which each statement begins with the word all, some, or no.For Example: •All cats are mammals. •All mammals are warm-blooded.• So, all cats are are warm blooded.ARG UM EN T BY E L I MIN ATIONAn argument by elimination seeks to logically rule out various possibilities until only a single possibility remains. Bassham is really into murder mysteries!•Either Dutch committed the murder, or Jack committed the murder, or Celia committed the murder. If Dutch or Jack committed the murder, then the weapon was a rope. The weapon was not a rope. So, neither Dutch nor Jack committed the murder. Therefore, Celia committed the murder.A R G U M E N T B A S E D O N M AT H E M AT I C SIn an argument based on mathematics, the conclusion is claimed to depend largely or entirely on some mathematical calculation or measurement (perhaps in conjunction with one or more nonmathematical premises).But sometimes these arguments are inductive, that is, it is possible for the premises to be true but the conclusion false!•My blind uncle told me that there were 8 men, 6 women, and 12 kids at the party.•By simple addition, therefore, it follows that there were 26 people at the party.A R G U M E N T F R O M D E F I N I T I O NIn an argument from definition, the conclusion is presented as being “true by definition,” that is, as following simply by definition from some key word or phrase used in the argument.•Emily is a gynecologist. Therefore, Emily is a doctor. These are necessary arguments and therefore deductive!SUMMARYArguments by elimination and arguments from definition should always be treated as deductive.Logically reliable hypothetical syllogisms, categorical syllogisms, and arguments based on mathematics should always be treated as deductive.Logically unreliable hypothetical syllogisms, categorical syllogisms, and arguments based on mathematics should be treated as deductive unless there is clear evidence that they are intended to be inductive.C O M M O N PAT T E R N S O F I N D U C T I V E R E A S O N I N Ginductive generalization predictive argument argument from authoritycausal argumentstatistical argument argument from analogyI N DU C T I V E G E N E RA L I Z AT I O NA generalization, as that term is used in critical thinking, is a statement that attributes some characteristic to all or most members of a given class. •Most Drexel students are from Philly.An inductive generalization is an argument in which a generalization is claimed to be probably true based on information about some members of a particular class.•All dinosaur bones so far discovered have been more than sixty-five million years old.•Therefore, probably all dinosaur bones are more than sixty-five million years old.PREDICTIVE ARGUMENTA prediction is a statement about what may or will happen in the future. In a predictive argument, a prediction is defended with reasons. Predictive arguments are among the most common patterns of inductive reasoning. Here are two examples:•It has rained in Vancouver every February since weather records have been kept. Therefore, it will probably rain in Vancouver next February.A R G U M E N T F R O M A U T H O R I T YAn argument from authority asserts a claim and then supports that claim by citing some presumed authority or witness who has said that the claim is true.•There are bears in these woods. My neighbor Frank said he saw one last week.CAUSAL ARGUMENTA causal argument asserts or denies that something is the cause of something else. •I can’t log on. The network must be down.We can rarely, if ever, be 100 percent certain that one thing causes, or does not cause, something else. For that reason causal arguments are usually best treated as inductive.AR GUM E NT F ROM AN ALOGYAn analogy is a comparison of two or more things that are claimed to be alike in some relevant respect. In an argument from analogy, the conclusion is claimed to depend on an analogy (i.e., a comparison or similarity) between two or more things.STATISTICAL ARGUMENTA statistical argument rests on statistical evidence—that is, evidence that some percentage of some group or class has some particular characteristic.IN CONCLUSION…Inductive generalizations, by definition, are always inductive.Predictive arguments, arguments from authority, causal arguments, statistical arguments, and arguments from analogy are generally, but not always, inductive.FOR NEXT TIME…Journal 3 Due Wednesday!Read Bassham 73-85Complete the Discussion Board activities!----------------------------------------------------Remember--Quiz this Thursday! •You will have ONE hour to complete the quiz on BB. The quiz will already submit after one hour unless you’ve already submitted it!•You are only allowed ONE attempt! So, once you open the quiz, you have to complete it then. •42 multiple choice questions.•Open