George Berkeley
George Berkeley (12 March 1685 – 14 January 1753), also known as Bishop Berkeley, was an Irish philosopher. He is best known for developing an early form of idealism, according to which the only things which exist are minds and the ideas which they perceive. The University of California, Berkeley, and the city that grew up around it were both named after him.
Contributions to philosophy
Berkeleyan idealism
The central thesis of Berkeley's idealism was that only minds and the ideas which they perceive exist. This committed him to immaterialism, the position that there are no material substances, where a substance is something which could exist even if nothing else did. According to Berkeley, objects like trees and chairs existed, but they could not exist independently of being perceived by a mind. He summarised this position with his famous dictum, "Esse est percipi" ("To be is to be perceived").