Philosophy 1100 Class #7 Title: Critical Reasoning Instructor: Paul Dickey E-mail Address: pdickey2@mccneb.edu Website: http://mockingbird.creighton.edu/NCW/dickey.htm Tonight: Submit Mid-term Exam Re-take Questions on Final Class Essay? – DUE 11/10 Class Presentations on assigned fallacy & Discussion of Chapters 7 & 8 Next Week: Portfolio #6 Student Portfolio is Due Read Chapter 9, pp. 243- 251, 255-270. pp.272-274 Exercise 9-2. 1

Portfolio Assignment #6 What is formal Deductive Logic and is it relevant to your life? ·         “Collect” from your daily experience 2-3 “artifacts” that describe a use of a formal logical argument and show its relevance to daily living. ·         For each, write a description or explanation of the artifact selected and evaluate for yourself whether this shows whether formal deductive logic is significant in your life. (1 paragraph) ·         Write a brief assessment of your analyses of Rhetoric & Logical Fallacies in Section #5 of your portfolio.

Chapter Seven / Eight: Logical Fallacies Presenters: Dottie: Generalizations, etc. ( pp. 197-202) Nicole: The Weak Analogy (pp 202-203) & & Various appeals to Popularity ( pp. 204-206) Paul: Fallacies Related to Cause & Effect (pp. 207-213) Justin: Slippery Slope & Untestable Explanations (pp. 213-214) & Three Formal Fallacies (pp.222-225) Megan: Equivocation and Amphiboly & Composition/Division, Confusing Explanation & Excuses & Contraries / Contradictories (pp. 225-231) Kim: Consistency/Inconsistency & Miscalculating Probabilities (pp 231-235) In your presentation, you must define your fallacy type, give examples, and distinguish it from other logical fallacies that are similar. I encourage you to use powerpoint slides in your presentation if possible, but it is not required. 3

Chapter Nine Deductive Arguments: Categorical Logic 4

Categorical Logic Consider the following claims: 1. Everybody who is ineligible for Physics 1A must take Physical Science 1. 2) No students who are required to take Physical Sciences 1 are eligible for Physics 1A. Are these different claims or the same claim? Categorical logic is important because it gives us a tool to work through the confusion with a technique to answer that question clearly. Such is done through the use of standard logic forms. 5

Categorical Logic Categorical Logic is logic based on the relations of inclusion and exclusion among classes. That is, categorical logic is about things being in and out of groups and what it means to be in or out of one group by being in or out of another group. 6

Four Basic Kinds of Claims in Categorical Logic (Standard Forms) A: All _________ are _________. (Ex. All Presbyterians are Christians. E: No ________ are _________. (Ex. No Muslims are Christians. ___________________________________ I: Some ________ are _________. (Ex. Some Arabs are Christians. O: Some ________ are not _________. (Ex. Some Muslims are not Sunnis. 7

Four Basic Kinds of Claims in Categorical Logic What goes in the blanks are terms. In the first blank, the term is the subject. In the second blank goes the predicate term. A: All ____S_____ are ____P_____. (Ex. All Presbyterians are Christians. 8

Venn Diagrams 9

Categorical Logic The Four Basic Kinds of Claims in Categorical Logic can be represented using Venn Diagrams. (See page 256 in textbook.) The two claims that include one class or part of a class within another are the affirmative claims (I.e. the A-claims & the I-Claims. The two claims that exclude one class or part of a class from another are the negative claims (I.e. the E-claims and the O-claims. 10

Translating Claims into Standard Form for Analysis The Bottom Line? Translating Claims into Standard Form for Analysis Two claims are equivalent claims if, and only if, they would be true in all and exactly the same circumstances. Equivalent claims, in this sense, say the same thing. Equivalent claims will have the same Venn Diagram. 11

Some Tips The word “only” used by itself, introduces the predicate term of an A-claim, e.g. “Only Matinees are half-price shows” is to be translated as “All half-price shows are matinees” The phrase “the only” introduces the subject term of an A-claim, e.g Matinees are the only half-price shows” also translates to “All half-price shows are matinees.” Claims about single individuals should be treated as A-claims or E-claims, e.g. “Aristotle is left-handed” translates to either “Everybody who is Aristotle is left handed” or “No person who is Aristotle is not left-handed.” 12