PHL 312 Symbolic Logic
Fall Semester 1998
Dr. Kevin Graham, Instructor
Office: Humanities Center, Room 113
Email: kgraham@creighton.edu
Telephone: 280-1219
Class Meetings. M W F 1:30-2:20 in Humanities Center, Room 316
Office Hours. M Tu W Th 2:30-3:20
or by appointment
Course Description
This course is a study of the formal analysis of reasoning employing the state-of-the-art tools of modern symbolic logic. We will translate arguments stated in a natural language (in this case, English) into symbolic form and then use the methods of symbolic logic to determine whether those arguments are valid or invalid. As the course progresses, we will employ successively more sophisticated tools of analysis. First, we will use sentential logic to assess the validity and invalidity of arguments at the level of sentences. Next, we will employ the more finely tuned tools of monadic predicate logic to demonstrate the validity of some arguments that appear invalid when analyzed with the coarser instruments of sentential logic. Finally, we will attain further precision of analysis by employing the tools of general predicate logic, also known as first-order logic with identity.
There are at least three good reasons for a philosophy student to study symbolic logic. (1) Modern symbolic logic is the most powerful and sophisticated tool that we have for analyzing reasoning. For this reason, those who want to improve their reasoning skills would be well advised to study symbolic logic. (2) Modern symbolic logic is perhaps the most important theoretical tool of twentieth century Anglo-American philosophy. Thus anyone who wants to understand contemporary English-language philosophy needs to have a solid grounding in the elements of symbolic logic. (3) Since at least the time of Leibniz, philosophers have sought to analyze natural-language reasoning in a symbolic, quasi-algebraic way so that disputes about the validity of an argument could be resolved by stating the argument formally and checking its steps mechanically. Modern symbolic logic is the closest we have come to completing this search. Along the way, logicians have sometimes had to sacrifice accuracy in the translation of natural language arguments for the sake of obtaining inference rules that permit us to check arguments’ validity mechanically. This raises the interesting philosophical question of whether modern symbolic logic accurately captures our notion of a valid argument, or whether it strays from this notion in order to attain formal rigor. We will discuss this question and others related to it in class and you will have the opportunity to write essay questions on this subject on the class tests.
Required Text
Graeme Forbes, Modern Logic: A Text in Elementary Symbolic Logic (Oxford UP)
Grading Scheme
Three class tests and one final examination, worth 15% each (60%)
Approximately eight to ten quizzes, each graded on a 20-point scale (30%)
Participation in class discussions (10%)
Course Requirements
Make-up Tests. If you miss an exam or a class test due to reasons beyond your control, then you can arrange to take a make-up exam or test by contacting the instructor as soon as possible, and no more than 24 hours after the scheduled time of the exam or test. In order to obtain permission to take a make-up test or exam, you need to provide documentary proof of the circumstances that prevented you from writing the exam or test at the scheduled time within 5 business days of the scheduled time. If you fail to contact the instructor within 24 hours or to provide evidence of what prevented you from taking the test within 5 business days, then you will receive a grade of zero for that test or exam.
Academic Honesty. If you present the words or thoughts of another person as if they were your own, you are guilty of plagiarism. This is true whether or not you intended to pass off the words or thoughts in question as your own. You are also guilty of plagiarism if you present the same work for credit in two different university courses. Plagiarism is an extremely serious academic offense. Penalties for plagiarism can range from getting a zero on the assignment in question through getting an F in the course to being expelled from the university. Plagiarism is also relatively easy for the experienced instructor to spot, so it is difficult to get away with. Given the severe penalties you may incur as a result of plagiarism and the high risk of getting caught, it is wise to do all in your power to avoid committing plagiarism knowingly or unknowingly.
Criteria for Evaluating
Written Work in Philosophy
Appropriateness. Does your essay satisfy each of the requirements specified in the handout you received in class? Will it be obvious to the reader how your essay satisfies each of those requirements?
Clarity of exposition and argument. How clearly have you explained the relevant readings? How clearly have you expressed your critical evaluation of the arguments contained in the readings? Have you clearly stated the reasons behind your evaluations?
Critical understanding of the material. Have you demonstrated a detailed, thorough understanding of the relevant readings? Is there any important part or aspect of an argument that you have not considered? Do your accounts of the arguments make sense in light of what you know about the larger context in which they are set (i.e. the book or article as a whole)?
Fairness to the authors' arguments. Are your interpretations of the authors’ arguments charitable? Have you done your best to interpret them as good, strong arguments? If you think a certain argument is badly flawed, have you supplied an argument to support that evaluation?
Coherence of your explanations and arguments. Does your essay make sense as a whole? Does your introduction make clear what your essay is trying to accomplish? Is it clear how each part of your essay serves the overall goal which you set out in your introduction? At each stage of the essay, is it easy to tell what you are saying and how that fits in with what you have already said? Are there any conflicts between things you say at different points in the essay? Do your arguments flow logically from your premises to your conclusions?
Ability to anticipate objections to your point of view. Have you considered how the authors of the articles you discuss (or someone else who read your essay and disagreed with you) might respond to your arguments? Are your arguments open to any obvious objections? Have you committed any glaring errors of reasoning? Are any of the assumptions you make obviously false?
Documentation of works cited. Have you noted where you refer to the work of writers other than yourself? Have you included page numbers in parentheses in the text of your essay to mark where you refer to works on the course syllabus? Have you included full endnotes or footnotes to mark where you refer to works other than those on the course syllabus? Have you included a bibliography listing all the bibliographical information about books you refer to which are not on the course syllabus?
Interpretation of Letter Grades
F "Failure – no credit"
D "Work of inferior quality, but passing"
C "Satisfactory work"
B "Noteworthy level of performance"
Demonstrates all of the qualities of satisfactory work, as well as:
A "Outstanding achievement and an unusual degree of intellectual initiative"
Demonstrates all of the qualities of noteworthy work, as well as:
Standards of Evaluation for
Participation in Class Discussions
F - extremely infrequent class attendance
- little or no participation in class discussions
D - infrequent class attendance
- limited participation in class discussions
C - regular class attendance
- limited participation in class discussions
B - regular class attendance
- regular participation in class discussions
A - regular class attendance
- regular participation in class discussions
- frequent thoughtful, insightful, or provocative contributions to class discussions
Percentile Equivalents
of Letter Grades
A = 93-100
B+ = 88-92
B = 82-87
C+ = 77-81
C = 70-76
D = 60-69
F = 0-59
Schedule of Required Readings
All readings taken from Forbes, Modern Logic: A Text in Elementary Symbolic Logic.
DATE |
READING |
Aug. 26 |
Introduction |
Aug. 28 |
Chapter 1: "What is Logic?", pp. 3-11 |
Aug. 31 |
Chapter 2: "First Steps in Symbolization", pp. 12-27 |
Sept. 2 |
Chapter 2: "First Steps in Symbolization", pp. 27-34 |
Sept. 4 |
Chapter 2: "First Steps in Symbolization", pp. 35-44 |
Sept. 7 |
Labor Day – No class meeting |
Sept. 9 |
Chapter 3: "Semantics for Sentential Logic", pp. 45-53 |
Sept. 11 |
Chapter 3: "Semantics for Sentential Logic", pp. 53-62 |
Sept. 14 |
Chapter 3: "Semantics for Sentential Logic", pp. 62-67 |
Sept. 16 |
Chapter 3: "Semantics for Sentential Logic", pp. 74-85 |
Sept. 18 |
Review for Class Test |
Sept. 21 |
Class Test on Chapters 1-3 |
Sept. 23 |
Chapter 4: "Natural Deduction in Sentential Logic", pp. 86-99 |
Sept. 25 |
Chapter 4: "Natural Deduction in Sentential Logic", pp. 100-08 |
Sept. 28 |
Chapter 4: "Natural Deduction in Sentential Logic", pp. 109-16 |
Sept. 30 |
Chapter 4: "Natural Deduction in Sentential Logic", pp. 117-20 |
Oct. 2 |
Chapter 4: "Natural Deduction in Sentential Logic", pp. 120-28 |
Oct. 5 |
Chapter 4: "Natural Deduction in Sentential Logic", pp. 133-45 |
Oct. 7 |
Review for Class Test |
Oct. 9 |
Class Test on Chapter 4 |
Oct. 12 |
Chapter 5: "Predication & Quantification in English", pp. 149-58 |
Oct. 14 |
Chapter 5: "Predication & Quantification in English", pp. 158-65 |
Oct. 16 |
Chapter 5: "Predication & Quantification in English", pp. 165-69 |
Oct. 19-23 |
Fall Break – No Class Meetings |
Oct. 26 |
Chapter 6: "Validity & Provability in Monadic Predicate Logic", pp. 170-79 |
Oct. 28 |
Chapter 6: "Validity & Provability in Monadic Predicate Logic", pp. 180-85 |
Oct. 30 |
Chapter 6: "Validity & Provability in Monadic Predicate Logic", pp. 185-88 |
Nov. 2 |
Chapter 6: "Validity & Provability in Monadic Predicate Logic", pp. 188-95 |
Nov. 4 |
Chapter 6: "Validity & Provability in Monadic Predicate Logic", pp. 195-204 |
Nov. 6 |
Chapter 6: "Validity & Provability in Monadic Predicate Logic", pp. 204-07 |
Nov. 9 |
Chapter 6: "Validity & Provability in Monadic Predicate Logic", pp. 207-11, 216 |
Nov. 11 |
Review for Class Test |
Nov. 13 |
Class Test on Chapters 5-6 |
Nov. 16 |
Chapter 7: "Advanced Symbolizations", pp. 219-31 |
Nov. 18 |
Chapter 7: "Advanced Symbolizations", pp. 231-41 |
Nov. 20 |
Chapter 7: "Advanced Symbolizations", pp. 241-49 |
Nov. 23 |
Chapter 8: "Validity & Provability in First-Order Logic With Identity", pp. 250-57 |
Nov. 25-27 |
Thanksgiving Break – No class meetings |
Nov. 30 |
Chapter 8: "Validity & Provability in First-Order Logic With Identity", pp. 257-62 |
Dec. 2 |
Chapter 8: "Validity & Provability in First-Order Logic With Identity", pp. 263-69 |
Dec. 4 |
Chapter 8: "Validity & Provability in First-Order Logic With Identity", pp. 269-74 |
Dec. 7 |
Chapter 8: "Validity & Provability in First-Order Logic With Identity", pp. 275-82 |
Dec. 9 |
Chapter 8: "Validity & Provability in First-Order Logic With Identity", pp. 283-92 |
Dec. 11 |
Review for Final Examination |
Dec. 18 |
Final Examination, 10:00-11:40 am |