George Berkeley, an Anglo-Irish Anglican bishop, was one of the great philosophers of the modern era. He is known for his empiricist and idealistic philosophy. Idealism is the belief that everything that exists depends upon the mind for its existence and that reality consists of whatsoever is perceived by the senses. He is regarded as one of the three most influential British Empiricists along with John Locke and David Hume. Berkeley is the major contributor to the theory of ‘Subjective Idealism’ that claims that that the only things that exist are the minds and contents perceived by the minds. The theory is associated with ‘Immaterialism’, an assumption that material things do not exist. He was of the belief that all physical objects ‘exist’ because they are perceived to be in the minds of the individuals. He felt that perception could be the actual perception of an entity that an individual has or the possible perception if the individual perceived something in a particular manner. As a metaphysicist, he criticized the idea of materialism, and focused on the study of the relationship between mind and matter, the nature of reality, fact and value, etc. He produced many texts on philosophy, the major one being ‘A Treatise Concerning the Principles of Human Knowledge’.