George Berkeley (12 March 1685 – 14 January 1753) – known as Bishop Berkeley (Bishop of Cloyne) – was an Irish philosopher whose primary achievement was the advancement of a theory he called "immaterialism" (later referred to as "subjective idealism" by others). This theory denies the existence of material substance and instead contends that familiar objects like tables and chairs are only ideas in the minds of perceivers and, as a result, cannot exist without being perceived, an idea which reminds of the Copenhagen interpretation of quantum physics. Berkeley is also known for his critique of abstraction, an important premise in his argument for immaterialism. Berkeley was the namesake of the city of Berkeley, California, which is most famous as the home of the University of California, Berkeley. Note, however, that his name is properly pronounced Barclay. Less