Propositional logic is the simplest form of logic that uses propositions that are either true or false. A proposition is a declarative statement. Propositional logic represents knowledge using symbolic variables and logical connectors. There are two types of propositions: atomic propositions which are single statements, and compound propositions which combine simpler propositions using logical connectors like AND and OR. Propositional logic is also known as Boolean logic as it uses 1s and 0s to represent true and false values.