PHIL 216 is an introduction to various modal logics, broadly construed. We will investigate basic modal logic, as it is commonly referred to, but will also investigate several “non-classical logics”, including conditional logics, intuitionistic logic, many-valued logics, relevant logics and paraconsistent logics. We will use possible worlds semantics to analyse these logical systems, as well as tableaux (called truth-trees in PHIL101). Applications to metaphysics and philosophy of language will be touched upon, allowing for optional research projects. This paper will help to provide you with the philosophical and mathematical sophistication required for further logical studies at stage III. You will learn some fundamental logical skills required to understand and study various logical systems - primarily truth-trees, meta-theoretical reasoning, and "informal" (mathematics-style) proofs with different semantic definitions. The focus will be on proving validity, and providing counter-examples for invalidity, in a range of systems.