Exam 1 Study Guide
Exam 1 Study Guide Philos 1500
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This 6 page Study Guide was uploaded by Kaitlyn Herbst on Tuesday February 10, 2015. The Study Guide belongs to Philos 1500 at Ohio State University taught by Peter Celello in Spring2015. Since its upload, it has received 303 views.
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Date Created: 02/10/15
Exam 1 Chap122 Philos 1500 Intro to Logic Vocab Logic study of methods for evaluating whether the premises of an argument adequately support its conclusion Deductive logic part of logic concerned with the study of methods of evaluating arguments for validity and invalidity Inductive logic part of logic concerned with the study of methods of evaluating arguments for strength and weakness Statement declarative sentence that is either true or false Argument set of statements where some of the statements called the premises are intended to support another called the conclusion Conclusion claim to be supported is also a statement Premises statements offered in support of the conclusion Deductive argument one in which the premises are intended to guarantee the conclusion Inductive argument is one in which the premises are intended to make the conclusion more probable without guaranteeing it Valid argument one in which it is necessary that if the premises are true then the conclusion is true Invalid argument one in which it is not necessary that if the premises are true then the conclusion is true Sound argument valid argument in which all of the premises are true Unsound argument one that is either invalid or has at least one false premise Argument form pattern of reasoning Substitution instance argument that results from uniformly replacing the variables in that form with statements or terms Valid argument form one in which every substitution instance is a valid argument Formally valid argument one that is valid in virtue of its form Negation denial Conditional statement ifthen statement Antecedent ifclause of a conditional Consequent thenclause of a conditional Disjunction eitheror statement Disjuncts statements comprising disjunction Invalid argument form one that has some invalid substitution instances Counterexample substitution instance in which the premises are wellknown truths and the conclusion is a wellknown falsehood Categorical statement relates two classes or categories where a class is a set or collection of things Term word or phrase that stands for a class of things Strong argument one in which it is probable but not necessary that if the premises are true then the conclusion is true Weak argument one in which it is not probable that if the premises are true then the conclusion is true Cogent argument strong argument in which all of the premises are true Uncogent argument one that is either weak or strong with at least one false premise Unsupported assertions Passages that are not arguments Unsupported Assertions include Reports Sets of statements intended to provide information about a situation topic or event Illustrations Statements together with explanatory or clarifying examples Explanatory statements Statements that provide a causal or other reason for some phenomenon Conditional statements ifthen statements Wellcrafted version of an argument is an argument that is stated in such a way that its important logical features are explicit Premise indicators words that are typically followed by a premise Conclusion indicators words that are typically followed by a conclusion Excess verbiage word or statement that adds nothing to the argument Discount Acknowledgment of a fact or possibility that might be thought to render the argument invalid weak unsound or uncogent Rhetorical elements increase an argument s psychological persuasiveness without affecting the validity strength soundness or cogency Repetition restate a premise or conclusion Sometimes altering the wording slightly Assurance statement word or phrase that indicates that the author is con dent of a premise or inference Hedge statement word or phrase that indicates that the arguer is tentative about a premise or inference Enthymemes argument that has one or more premises or its conclusion left implicit Famous Valid Forms MOdUS POWquot395 Modus tollens onstructive dilemma 1 If A then B 1 If A then B 1 Either A or B 2 A 2 NOt B 2 If A then C 3 If B then D 50 3 B So 3 Not A So 4 Either C or D Hypothetical syllogism Disjunctive 1 If A then B syllog39sm 2 If B then C 1 Either A or B So 3 If A then C 2 Not A Famous Fallacies Fallacy of denying the antecedent Fallacy of af rming the 1 f A then B consequent 239 NOtA39 1 lfA then B 50 3 Not B 2 B Sn 3 A Famous forms Method 1 Identify the component statements in the argument uniformly labeling each with a capital letter 2 Rewrite the argument using capital letters instead of English statements and eliminate any stylistic variants 3 Check to see whether the pattern of reasoning is taken from our list of famous forms Counterexample Method 1 2 Identify the most logically sensitive form of the argument Use capital letters to stand for statements or terms Find English statements or terms that if substituted for the capital letters in the conclusion of the argument form produce a wellknown falsehood Substitute these English statements or terms for the relevant capital letters uniformly throughout the argument form Find English statements or terms that if substituted uniformly for the remaining capital letters in the argument form produce premise that are wellknown truths Check your work If you have succeeded you have shown the argument to be invalid Categorical Arguments 1 All A are B 2 All B are C So 3 All A are C Validity Preserves Truth if start with truths and reason in a valid fashion will always end up with truth Validity does not preserve falsehood Help distinguish arguments vs nonarguments Premise and conclusion indicator words usually indicate argument 0 Because can be used in explanatory statements 0 So 0 Thus can be used to introduce illustrations 0 Therefore 0 quotDo the examples merely clarify or explain a statement or are they used to provide evidence for itquot o If provide evidence then passage is argument Unsupported assertions nonarguments No inferences are drawn 0 Reports Illustrations Explanatory statements Conditional statements Arguments in plain English are often stated in ways that obscure important logical features 0 Conclusion could be in and amongst premises Repetition could make it appear there are many premises when there are actually few Verbiage could make it dif cult to determine what the premises are Unhelpful variation in vocabulary can obscure links between premises Principles for Rewriting Arguments as WellCrafted Ones Identify the premises and the conclusion Eliminate excess verbiage discounts repetition assurances hedges Employ uniform language Be fair and charitable in interpreting an argument Do not confuse subconclusions with nal conclusions Make explicit obviously implicit premises in a charitable way PP PPP J DeducU Induch ve Logic e Logic e argume n39lc ILJ J H H mew J JmmJeogentnw argume n39lc ILJ
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