Berkeley was born at Dysert Castle, near Thomastown, Ireland, on March 12, 1685. He studied at Trinity College Dublin and received a B.A. (1704), M.A. and fellow (1707). He filled various college offices includ ing tutor, Junior Dean, and Junior Greek Lecturer. He lived there in an atmosphere "charged with the elements of reaction against traditional scholasticism in physics and metaphysics." His Philosophical Commentaries (first printed in 1871 under the title Common-Place Book) was written from time to time during his undergraduate years as a kind of scrapbook of thoughts. The work indicates the great formative influence of Locke's Essay which was a text book at Trinity College, and appear s to have excited Berkeley to independent critical activity. In 1709 he published an Essay toward a New Theory of Vision, an examination of visual consciousness to prove that it affords no ground for belief in the reality of the objects apparently seen. In 1710 appeared a Treatise concerning the Principles of Human Knowledge, which presents the theory of idealism, for which he is best remembered.

Berkeley took holy orders, and, in 1713, he left Dublin, went to London and formed acquaintances. The same year he published Three Dialogues Between Hylas and Philonous, a popularized and lively account of the theory of idealism as appears in his Principles. He visited continental Europe in 1713-14 and again in 1716-20. During this period he did little literary work. Although he made some progress with the second part of his Principles, the manuscript was lost in his travels and the work was never resumed. His Latin treatise De motu was written as he was on his way home and published in 1721. Back in England, he became concerned with what he witnessed as a nationwide decline in religion, decay of public spirit, and corrupt ion of manners. The result was his Essay towards preventing the ruin of Great Britain, published anonymously in 1721. That same year he returned to Ireland, earned his B.D. and D.D. (1721), and again filled college offices including Divinity Lectur er, Senior Lecturer, Hebrew Lecturer, Proctor, Dean of Dromore, and Dean of Derry.

He now became devoted to a plan of establishing a college in the Bermuda Islands, went to London to further the project in 1724, and in 1725 published A Proposal for the Better Supplying of Churches in our Foreign Plantations, and for converting t he savage Americans to Christianity by a college to be erected in the Summer Islands, otherwise called the Isles of Bermuda. By his enthusiasm and persuasiveness, he won many expressions of sympathy, and came to believe that the government would suppo rt the plan. In September 1728, he sailed for America and landed at Newport, Rhode Island. On arrival he bought a farm near Newport and built a house which he called "Whitehall" after the English palace. The shoreline, about a mile from the house, had a cleft in the rocks which became a retreat for writing and reflection. He helped found a philosophical society at Newport and preached there in Trinity Church, a old wooden structure. He influenced Reverend Samuel Johnson, episcopal missionary and later fi rst president of Columbia College, New York. The new world affected Berkeley's imagination and led to a set of Verses on the prospect of planting arts and learning in America.

Three years of waiting on funding for his project convinced him that his hopes were futile, and in February 1732 he returned to London. He published immediately Alciphron or the Minute Philosopher, the result of his studies in America. It is a polemic against deists whom he identifies with atheists, and designates as "minute philosophers" because of their inability to take large views of things. In 1733 appeared his Theory of Vision, or Visual Language Vindicated and Explained. In the f ollowing year he published The Analyst, in which he criticized the positions of the new mathematics which, in his view, were connected with a materialistic conception of the world. This bold attempt to carry the war into the enemy's country prompte d many pamphlets in response. In 1734 he was made bishop of Cloyne. After this, his literary work was divided between questions of social reform and religious reflection. His concern for reform is represented in The Querist (1735). Other writings e xpress his faith in tar-water as a universal medicine, specifically his Siris, a Chain of Philosophical Reflections, and Inquiries concerning the Virtues of Tar-water (1744), in which he also revises his earlier views of idealism. Berkeley lived wi th his family in Cloyne until 1752, when he went to Oxford to end his days with his son, a senior student at Christ Church.

Berkeley's principal metaphysical position is idealism: nothing, including material objects, exists apart from perception; external objects are ultimately collections of ideas and sensations. From his earliest writin gs in the Philosophical Commentaries, Berkeley's idealism is evident. There he refers to his doctrine of "the immaterial hypothesis". Only persons exist: "all other things are not so much existences as manners of the existence of persons." He antic ipates that "a mighty sect of men will oppose me," that he will be called young, and upstart, a pretender, vain; but his confidence is not shaken: "Newton begs his principles; I demonstrate mine."