THE ROLE OF REASONING IN CONSTRUCTING A PERSUASIVE ARGUMENT RICHARD R. ORSINGER [email protected] http://www.orsinger.com McCurley, Orsinger, McCurley, Nelson & Downing, L.L.P. San Antonio Office: 1717 Tower Life Building San Antonio, Texas 78205 (210) 225-5567 http://www.orsinger.com and Dallas Office: 5950 Sherry Lane, Suite 800 Dallas, Texas 75225 (214) 273-2400 http://www.momnd.com State Bar of Texas 37TH ANNUAL ADVANCED FAMILY LAW COURSE August 1-4, 2011 San Antonio CHAPTER 11 The Role of Reasoning in Constructing a Persuasive Argument Chapter 11 Table of Contents I. THE IMPORTANCE OF PERSUASION.. 1 II. PERSUASION IN ARGUMENTATION.. 1 III. BACKGROUND.. 2 IV. USER’S GUIDE FOR THIS ARTICLE.. 2 V. ARISTOTLE’S THREE COMPONENTS OF A PERSUASIVE SPEECH.. 3 A. ETHOS.. 3 B. PATHOS.. 4 C. LOGOS.. 4 1. Syllogism.. 4 2. Implication.. 4 3. Enthymeme.. 4 (a) Advantages and Disadvantages of Commonplaces... 5 (b) Selection of Commonplaces.. 5 VI. ARGUMENT MODELS (OVERVIEW)... 5 A. LOGIC-BASED ARGUMENTS. 5 1. Deductive Logic.. 5 2. Inductive Logic.. 6 3. Reasoning by Analogy.. 7 B. DEFEASIBLE ARGUMENTS... 7 C. THE TOULMIN ARGUMENTATION MODEL... 7 D. FALLACIOUS ARGUMENTS.. 8 E. ARGUMENTATION SCHEMES.. 8 VII. LOGICAL REASONING (DETAILED ANALYSIS).. 8 A. DEDUCTIVE REASONING.. 8 1. The Categorical Syllogism... 8 a. Graphically Depicting the Simple Categorical Syllogism... 9 b. A Legal Dispute as a Simple Syllogism.. 9 c. Disputed Facts; Disputed Law.. 9 2. The Hypothetical Syllogism... 10 a. The Conditional Syllogism.. 10 b. The Conjunctive Syllogism... 10 c. The Disjunctive Syllogism.. 10 3. The Dilemma.. 10 4. Implication.. 10 a. Antecedent/Consequent... 11 b. Two Rules of Implication and Three Points to Remember... 11 c. Affirming the Antecedent (Modus Ponens).. 12 d. Denying the Consequent (Modus Tollens).. 12 e. Chaining Conditional Propositions.. 12 f. Enthymemes.. 13 g. Proof by Contradiction.. 13 h. Proof by Contrapositive.. 14 i. Disproof by Counterexample.. 14 -i- The Role of Reasoning in Constructing a Persuasive Argument Chapter 11 j. Attacking a Conditional Proposition... 14 k. Refuting a Deductive Argument.. 14 l. Refuting an Argument for Change.. 15 m. Refuting an Argument Over Trust Income.. 15 B. INDUCTIVE REASONING... 15 1. Generalization.. 15 2. Simple Induction.. 15 3. Correlation and Causation.. 15 4. Statistical Syllogism... 15 5. Statistical Prediction.. 16 6. The Counting Marbles Example.. 16 7. Counterexamples in Inductive Reasoning.. 16 8. Cognitive Studies of Inductive Reasoning... 16 9. Generating Rules to Resolve Legal Cases.. 16 C. REASONING BY ANALOGY.. 17 1. Terms of Analogical Reasoning... 18 2. Comparing Deductive, Inductive and Analogical Reasoning.. 19 3. The Process of Analogical Reasoning.. 20 a. Retrieval.. 20 b. Mapping.. 20 c. Projection.. 21 d. Evaluating the Analogy... 21 4. The Use of Examples.. 21 5. Arguments by Analogy.. 21 6. Judging the Validity of an Analogy.. 22 7. Using Analogical Reasoning With Case Law.. 23 8. Analogies are More Than Just Words.. 23 9. The Power of Metaphors In the Law.. 24 VIII. DEFEASIBLE ARGUMENTS (DETAILED ANALYSIS).. 25 A. NOT TRUTH, BUT PRIMA FACIE ACCEPTABILITY.. 26 B. DEFEASIBLE ARGUMENTS IN LAW.. 26 IX. THE TOULMIN ARGUMENTATION MODEL (DETAILED ANALYSIS).. 28 A. THE MAN AND THE TIMES.. 28 B. OVERVIEW OF TOULMIN’S MODEL.. 29 C. THE COMPONENTS OF THE TOULMIN MODEL.. 30 1. Claims.. ..