This course consists of two parts. The first part introduces the basic methods of modern formal logic. Topics will include propositional logic and predicate logic. Special emphasis will be given to validity and soundness of arguments, truth-functions and truth-tables, and natural deduction. The second part discusses some philosophical problems raised by modern formal logic: What is validity? How does formal logic help one to understand the validity of informal arguments? What is logical truth? Can logical truth be understood outside formal logic? How do we recognize a valid argument or a logical truth?