an Anglo-Irish philosopher whose primary achievement was the advancement of a theory he called "immaterialism" (later referred to as "subjective idealism" by others). In 1709, Berkeley published his first major work, An Essay towards a New Theory of Vision, in which he discussed the limitations of human vision and advanced the theory that the proper objects of sight are not material objects, but light and color. His last major philosophical work, Siris (1744), begins by advocating the medicinal use of tar water and then continues to discuss a wide range of topics, including science, philosophy, and theology.
