1、7/27/15 Recap: Varie9es of Reasoning •Reasoningisaninferentialmentalprocess–Acausallyconnectedsequencesofthoughts–Inwhichsomeofthethoughts(premises)supportorjustifyothersthoughts(conclusions)Reasoning (Cont.) •TheoreticalandPracticalReasoning–TRproducesbelieforjudgment
2、.–PRconcernswhattodo•Producesdecisionsorplans.–AKADecision-making•Twokindsoftheoreticalreasoning:–Inductivereasoning&deductivereasoningWhat is Deduc-ve Reasoning? •Yesterday: Focused on Induc9ve Reasoning •If one’s original beliefs (premises) are true, the conclusion m
3、ust also be true. –Specifically: Looked at some of the characteris9c errors – and the explana9ons of those errors – in reasoning about –When this condi9on holds, a piece of reasoning is said to be valid. probabili9es. –Otherwise it is invalid. •Famous Example: •Today: 1
4、.All men are mortal 2.Socrates is a man –Deduc9ve Reasoning 3.So: Socrates is mortal –Prac9cal Reasoning and decision making •Providing an account of good deduc9ve reasoning is widely viewed as a goal of formal logic. xxx-xxx_CH010_12708_Abb.qxp12/23/0511:50AMPage12Kin
5、ds of deduc,ve reasoning SyllogismsSeriesproblems12PART5■THEHUMANINTELLECT•Seria-on (series problems) •Presenttwogeneral•reviewseriesofstatements•Review series of statements Table10.1
6、premisesthatmustbe•arriveataconclusionnotcontainedinanysingle•Arrive at a conclusion
7、 not contained in any single Deductive-reasoningproblemscombinedtoseeifastatementstatement. particularconclusionisSeriesproblemSyllogism•Forexample:–Examples: JohnistallerAllchefsarevioliniststrueAnswers:thanHenry.(majorpremise).indeterminate,no.)•RobinisfunnierthanBil
8、lyJohnisshorterMaryisachef(minorpremise).indeterminate,•BillyisfunnierthanSinbadthanMary.IsMaryaviolinist?(Alternativeforms:MaryisshorterAlternativeforms,basedonyes.Syllogism:•WhoopiisfunnierthanBillythanBilly.differentminorpremises:no.•Goes back to Aristotle Seriespr
