George Berkeley
George Berkeley (March 12, 1685-January 14, 1753) was an Irish philosopher who advanced an empiricist and idealistic philosophy, such that aside from the spiritual, nothing exists except it is perceived by the senses (tangible, empirical objects). Reduced to its essence he said, “'To be,' said of the object, means to be perceived; 'to be,' said of the subject, means to perceive." Key writings of his that support this philosophy include Arithmetica (1707), Essay Towards a New Theory of Vision (1709), A Treatise Concerning the Principles of Human Knowledge (1710), Three Dialogues Between Hylas and Philonous (1713), and Siris (1744).