Lecture #14 started to look at propositional logic. In particular it introduced the idea of logic, propositions, and the basic syntax and semantics of propositional logic.
Notes are available in two formats:
The lecture covered broadly the same material as Chapter 7 (up to page 210) of the textbook. It would be a good idea to look through this material, though bear in mind that the textbookcoevrs osme material we did not discuss.