Phi 170 - Spring 2020
## Intro to Logic

(pdf) - due Mar 19
We continue our study of
rules of derivation in propositional logic.
Negated formulas
(video,
slides)
Introduction and elimination rules
for "or"
(video,
slides)
Proof by cases
(video,
slides)
You should watch each video at least twice.
To strengthen your
learning, read my notes
on how to construct derivations
in propositional logic
(including rules for disjunction)
(pdf).
If anything is unclear, ask questions in Slack.

## Intro to Logic

syllabus

### Midterm

### The course is now on-line

- All course materials (videos, handouts, assignments) will be provided through this website. Additional videos and on-line resources will be posted. For questions and discussions and to communicate with me, please use Slack. Do not use email if possible.
- Please work on hoemwork 6. The deadline has been extended by one week because of "recalibration period" mandated by the CUNY chancellor.

### Week 1: Jan 28 - No class on Jan 30

### Week 2: Feb 4 & Feb 6

### Week 3: Feb 11 & Feb 13

- How to prepare for the Tuesday class: complete homework #2 (pdf). To prepare for the Thursday class, make sure you watch and study the videos and slides below.
- Semantics of propositional logic (video, slides)
- Truth tables for "not", "and" and "or" (video, slides)
- Truth table for "implies" (video, slides)
- Truth of a formula (video, slides)
- You should watch each video at least twice. To strengthen your learning, also read section 2.5 of the textbook (pdf). If anything is unclear, feel free to email me and come to class with questions.

### Week 4: Feb 18 & Feb 20

- How to prepare for the Tuesday class: complete homework #3 (pdf). To prepare for the Thursday class, review the course materials covered during previous weeks.

### Week 5: Feb 25 & Feb 27

- How to prepare for the Tuesday and Thursday class: make sure you watch and study the videos below along with the slides.
- Validity of a formula (video, slides)
- Validity of PEM and PNC (video, slides)
- Validity of Modus Ponens and Modus Tollens (video, slides)
- You should watch each video at least twice. To strengthen your learning, read section 2.6 of the textbook (pdf). If anything is unclear, feel free to email me and come to class with questions.

### Week 6: Mar 3 & Mar 5

### Week 7: Mar 10 & Mar 12 - In-person classes canceled

- Please review the slides and watch the videos below to prepare for the midterm exam. Ask questions in Slack.
- Midterm review - syntax and semantics of propositional logic (slides)
- Sample exercises: breaking down a formul into a tree (video); checking truth of a formula (video); tautology (video); neither a tautology nor a contradiction (video); valid argument (video).

### Week 8: Instruction resumes on-line March 19

### Week 9: Mar 24 & Mar 26 - No in-person classes

- Please complete homework #5 (pdf).
- We will start learning about derivation rules. Watch the videos below.
- Derivations in natural deduction (video, slides)
- Introduction and elimination rules for "and" and "implies" (video, slides)
- Idempotency and commutativity (video, slides)
- Sample derivations: idempotency (video); commutativity (video); implication introduction (video).
- You should watch each video at least twice. To strengthen your learning, read my notes on how to construct derivations in propositional logic (up to page 5 only) (pdf). If anything is unclear, ask questions in Slack.

### Week 10: Mar 31 & Apr 2 - No in-person classes

### Week 11: Apr 7 & Apr 9 - Spring break

### Week 12: Apr 14 & Apr 16 - No in-person classes

### Week 13: Apr 21 & Apr 23 - No in-person classes

- We continue our study of rules of derivation in propositional logic. Review the derivation rules we studied last week. The sample derivations below should help you with the homework due next week.
- Sample derivations: non-contradiction (video); double negation (video); Modus Tollens (video).
- You should watch each video at least twice. To strengthen your learning, read the rest of my notes on how to construct derivations in propositional logic (pdf). If anything is unclear, ask questions in Slack.

### Week 14: Apr 28 & Apr 30 - No in-person classes

- Complete homework #7 (pdf). Once you completed it, please study the last set of derivation rules below.
- Rules for contradiction (video, slides)
- Proof by contradiction (video, slides)
- Consequentia mirabilis (video, slides)
- Sample derivations: double negation using RAA (video); derivation of consequentia mirabilis (video).
- Make sure you review all the videos and slides from earlier weeks. As usual, ask questions in Slack.

### Week 15: May 5 & May 7 - No in-person classes

- Complete homework #8 (pdf). This will be your last homework assignment and its format will be similar to the final exam. As usual, ask questions in Slack.