Born: 3/12/1685   Died: 1/14/1753

George Berkeley was a prominent 18th century Irish philosopher in the empiricist tradition, who wrote both essays and philosophical dialogues. Also known as Bishop Berkeley, he is famously known for his daring project in the Treatise Conerning the Principles of Human Knownedge to refute the existence of matter, by arguing that to be is to be perceived by means of ideas (esse ist percipi). In the end, his argument required the existnce of an all-perceiving God. Berkeley combined this idealism with a fierce rejection of John Locke's doctrine of abstract ideas, which introduced notions, such as the 'substratum', unrelated to sense experience, and foreign to common sense. The case against abstraction permeates his important contributions to scientific issues in optics (an empiricist account of the relation between sight and touch), and mathematics (the theoretical presuppositions of infinitesimal calculus). Berkeley's far-reaching interests also included economics, morals, medicine, and education.