Irish philosopher and Bishop in the Irish Anglican church, he is considered along with Locke and Hume to be one of the great Empiricists. A graduate of Trinity College in Dublin at the age of 19, he was elected to the college as a fellow by 1707, and was made Dean of Derry College in 1724. Most of his writing was done between 1707 and 1713.
His major works include his notebooks: Philosophical Commentaries(1707-08), and the books: &127;Essay Towards a New Theory of Vision(1709), Principles of Human Knowledge(1710), Three Dialogues Between Hylas and Philonous(1713), his Latin work, De Motu(1721), and three later works-- Alciphron(1734), The Analyst(1734), and A Defense of Free Thinking in Mathematics(1744).
Berkeley's earliest work, Vision was primarily a psychological explanation of sight, bordering on early philosophical significance. His Principles was perhaps his most influential work, dealing with such doctrines as abstract general ideas and his own idea of 'Berkeleyan Idealism.' He suggested that if an object is not perceived, it does not exist. Berkeley challenged Locke's assertions in his Essay, arguing that general abstraction, as it is suggested by Locke and even Plato is wrong. He asserts that some abstracted ideas are impossible objects, and that these are not necessary parts of learning and used language.(This is the principle impetus for Wittgenstein's Philosophical Investigations.) Berekeley's Idealism comes out of this theory: he rests his ideas of metaphysical realism, absolute spave, and absolute motion and time upon his assertions about abstract ideas.
In his Dialogues Berkeley argues that sensible qualities are ideas. He defends common sense, calls representative realism false, and argues for a positive conception of epistemology. Lastly, he argues against the existence of matter on the grounds that we have no sensible idea of it. He supports the idea that we learn about the existence and nature of ordinary physical objects by means of perception.