PHIL 120 A: Introduction to Logic

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Overview

What makes an argument good? How do you show that someone has reasoned invalidly? In this course we will study arguments and reasoning both informally as well as with the tools and techniques of formal deductive logic. We learn the syntax and semantics of propositional and first-order logic (polyadic with identity). We then apply our formal logical techniques to a variety of domains, such as the domain of sets (abstract collections of objects). Topics include syntax, semantics, pragmatics, consistency, proof, logical consequence, logical equivalence, logical truth, logical form, set theory, infinity, paradoxes, truth functionality, binary numbers, logic gates, truth tables, quantification, relations, functions, interpretations, models, soundness, and completeness. We also discuss connections between formal logic and computability theory, philosophy of language, cognitive science, the foundations of mathematics, and metalogic (theorems about logical systems themselves). Students will learn how to practice active learning and use goal-directed study habits. Students will also learn how to use AI to improve their logical skills and their studying. AI is allowed for homework and in-class activities, but not exams or skills checks; hence students must learn how to use AI as an aid rather than a crutch (AI use is optional, not required).

Course Structure

This course is in person. There is no remote option. (If you would like a remote option, we are teaching this same course fully online in Summer 2025 A term.) The midterm and final exams are also in person. The midterm exam is Thurs. of week 5. The final exam is in the slot assigned by the university. You should not enroll in this course unless you can commit to taking the exams in person at those times.

Prerequisites

None.

Grading and Course Requirements

There are five components of your grade:

1. In-Class Participation (via Poll Everywhere): 15%
2. Homework: 35%
3. Midterm Exam: 25% (see note below about skills tests and exam times)
4. Final Exam: 25% (see note below about skills tests and exam times)
5. Extra Credit: extra points added to exam grades

Here is an explanation of each part:

1. In-Class Participation: 15%. Participation in lecture is required via the response system Poll Everywhere. There is no device to buy: you can use a phone, tablet, or computer, or I will also allow you to answer by paper and pencil if you prefer (talk with me in advance if you would like to use that option). In-class participation means you must actually be in the classroom participating in order to earn these points. Your lowest three Poll Everywhere grades will be dropped, which accounts for sick days or other legitimate reasons to miss a class. Every poll question is worth 1 point. Many questions will be for participation only and all answers will get full credit (but you must still click in in order to get the points). Some questions only give full credit to correct answers, but incorrect answers still get ½ point for participating. Screens should only be used in class for answering Poll Everywhere questions, doing homework, or taking notes, not shopping or playing video games!
   
2. Homework: 35%. Homework problem sets are done as quizzes in Canvas. They are not done with the online textbook. The questions and problems in the textbook are for practice and are not worth points. You may take each Canvas quiz for homework five times. Your highest score will be counted. Working with other students in a study group on homework is allowed—learning from your peers is very beneficial! Homework assignments will start to be due the first week. They are typically due each Saturday by 11:59 p.m. The Canvas assignment is “available” until the next day, per the late policy; see below. You can see your score after submitting each homework quiz, which can help you improve your result if you choose to take it a second or third time. Each time you take a quiz, you must still answer all the questions. Correct answers will be posted at 12:01 a.m. the day after the quiz closes.

3. Midterm Exam 25%. The midterm will occur in lecture on Thursday of week 5. It is closed note/book/phone/computer/etc. (unless allowed by DRS) and must be done strictly individually (AI is not allowed on the exams or skills checks). It will be multiple choice, true/false, proofs, etc. Some of the questions will be previous clicker questions; others will be similar to homework questions. So your previous work in the course will have prepared you for what to expect. Directions and a study guide will be provided before the exam. You must bring a PURPLE (not green) Scantron answer card (bubble sheet) and a no. 2 pencil in order to take the test. Skills Checks: in Friday quiz sections of some weeks students will be able to take a skills check on that unit's material; the skills check score helps your exam score in this way: if you exam score is lower than your skills check score, your exam grade is an average of the two; if your exam score is higher, the skills check score is thrown out and you get the exam score.
   
4. Final Exam: 25%. The final exam will occur in our assigned slot during finals week. It is closed note/book/phone/computer/etc. (unless allowed by DRS) and must be done strictly individually (AI is not allowed on the exams or skills checks). Like the midterm, it will be multiple choice, true/false, proofs, etc. Some of the questions will be previous clicker questions; others will be similar to homework questions. So your previous work in the course will have prepared you for what to expect.  Directions and a study guide will also be provided during the last week of class. The test is cumulative, but the emphasis will be on new material since the midterm. You must bring a PURPLE (not green) Scantron answer card (bubble sheet) and a no. 2 pencil in order to take the test. Skills Checks: in Friday quiz sections of some weeks students will be able to take a skills check on that unit's material; the skills check score helps your exam score in this way: if you exam score is lower than your skills check score, your exam grade is an average of the two; if your exam score is higher, the skills check score is thrown out and you get the exam score.
   
5. Extra Credit. Besides the skills checks to improve your exam grade, there are several extra credit opportunities as well. Extra credit points are raw points added to your exam grades (post-averaging with skills checks, if applicable, which gives you maximal stacking). They are earned by completing optional assignments relevant for certain quiz section activities. In order to earn the extra credit points, you must BOTH complete the assignment AND participate in the relevant quiz section. Extra credit points in the first half of the quarter will be added to your midterm exam score; extra credit points in the second half of the quarter will be added to your final exam score. There is no make up for the extra credit points; there are additional incentive to practice in quiz section.