Abstract

C.I. Lewis never completed his final project on ethics. There are a few short papers published based on lectures that he has given in the 1950s, and a vast amount of draft materials that he was working on up until the time of his death in 1964. But his ultimate life project, the final book on ethics, never came to fruition. From the materials available, it seems that even towards the end of his life, Lewis was still adjusting and refining his view on how to answer the question “What is right?” That said, it is clear that the core arguments remain consistent throughout his works and draft manuscripts. The main goal of this paper is to reconstruct from the available materials the overall ethical framework Lewis was working towards; and to present the key arguments that lie at the heart of his ethical theory. In doing so, I will also attempt to show that Lewis’s pragmatic conception of the a priori developed in the 1920s actually plays a critical role in grounding his entire ethical view. This paper concludes with a brief evaluation of how well the argument based on a pragmatic a priori fares against the moral skeptic.