Introduction to Logic

This course will cover two major topics: basic formal sentential logic and informal fallacies of reasoning. We will first spend about three weeks on the formal side, which covers translation to formal notation, truth tables, and proofs by natural deduction. Then we will spend about two weeks on informal reasoning, which covers some of the major types of mistakes people make when reasoning.

Note that students in this class are expected to complete their own work on exams, and not copy from other students or any other source. Violation of this is plagiarism and constitutes a violation of class and University academic integrity policy.

Course Materials

The text for the course is Basic Sentential Logic and Informal Fallacies (BSLIF) by Rick Grush, which is available at the Price Center bookstore. This text is brief, and covers everything you will need to know, and nothing that you won't need to know. The text also contains practice exams for all exams (and solutions) including the final exam. So of all the materials for the course, it is probably the most important.

In addition to the text, there is a logic website for this course, which has additional exercises with solutions. Rick Grush, who has developed the content for this course, also maintains a YouTube channel, where you can find videos for all lectures and of him solving the practice exams. While I am not identical to Rick Grush, and there will thus be some differences in the presentation of the material (though not in content), this is an excellent resource for you to study the material.

The following materials are mandatory for this course:

  • Book: Rick Grush, Basic Sentential Logic and Informal Fallacies, available at the Price Center bookstore.

This document summarizes all inference and replacement rules on one sheet:

Please let me know if you come across great logic resources on the internet!

Grading Comments

Exam 1: The average was 87.7, with a rather large standard deviation of 20.1. The questions that not a few students got wrong are: Q2 (they chose (a)); Q3 (they chose (b) or (c)); Q7 (they chose (c)). In his grading, Tomoya tried to be charitable. If student's answers were logically equivalent to the correct one, he marked them correct. Even if students forgot putting parentheses, he marked them correct, as long as it was clear that the correct structures of statements was understood.

Exam 2: The average was 89, with a still rather large standard deviation of 19. Students struggled with the first two questions in particular: 70% students gave a wrong answer to Q1, 75% students gave a wrong answer to Q2. In particular, 50% students wrongly chose option (d) "All the needed rows are present".

Exam 3: Students did very well on this exam (was it too easy...?), and the average was 102. In fact, 45 students out of 81 students got the perfect score of 110. It seems that there was no particular question that was difficult for students.

Exam 4: As expected for Exam 4, the average went down, this time to 89.7. What is worrying about the outcome is that the standard deviation was a whopping 26.1 points, which strongly indicates that we have one group of students who did very well, and one group who did very poorly. Question 8 (the proof of the tautology) seems to have been hardest, with even most of those who did get it produced a longer proof than necessary (the shortest proof is six lines).

Exam 5: The class average for this exam was 98.7. Most students did a good job. In particular, many students gave correct answers to all multiple-choice questions (Q1-3 and Q6-12).

It seems that Q5 was not easy for students. 45 students out of 81 students who took the exam made a mistake on the question. They correctly identified the premises and the conclusion, but half of them answered that the argument commits an alternative description fallacy. Aristotle's claim is that everything is either black or *not black*. The claim that the arguer actually criticizes is that everything is either black or *white*. They are not two different descriptions of the same one thing: rather, they are different claims (the latter is a weaker claim than the former). The claim that the arguer had to refute is the former but the latter. Therefore, the answer is "strawman fallacy".

Final Exam: The class average for the final exam was a rather low 353.3 points with a rather large standard deviation of 55.5.