This chapter introduces key issues concerning knowledge and our reasoning powers that occupied philosophers in classical India and examines some of the issues underlying the notion of a good argument. In the philosophies of India ignorance is widely regarded as a principal source of suffering because it gives rise to the attachments that lead to rebirth. 'Philosophy' comes from a Greek word meaning 'love of wisdom', and philosophers seek to acquire wisdom by replacing ignorance with knowledge through their practice of philosophy: a practice that, in classical India, was largely constituted by public debate. The Naiyayikas developed a framework within which philosophical debates could proceed between parties holding opposing views. Philosophers from the various darsanas used the framework of debate outlined to argue with each other about many topics. The sceptics were as much a thorn in the side of the Naiyayikas as they were to modern philosophers in the western tradition, such as Rene Descartes.