George Berkeley

Early Life and Education

George Berkeley was born on March 12, 1685, at Dysart Castle near Thomastown, County Kilkenny, Ireland. He entered Trinity College Dublin at the age of fifteen, receiving his B.A. in 1704 and becoming a Fellow in 1707. It was during his years at Trinity that Berkeley developed the startling philosophical ideas that would make his reputation.

Berkeley's philosophical notebooks (the 'Philosophical Commentaries,' discovered only in the 19th century) reveal the evolution of his thought. By his early twenties, he had arrived at his central thesis: matter, understood as something existing independently of perception, is a philosophical fiction. All that exists are minds (spirits) and their ideas (perceptions). The physical world is constituted entirely by sensory experiences, sustained in continuous existence by the perpetual perception of God.

Early Philosophical Works

Berkeley published his major philosophical works at a remarkably young age. An Essay Towards a New Theory of Vision (1709), written at twenty-four, analyzed visual perception, arguing that we do not directly see distance, magnitude, or spatial location — these are inferred through learned associations between visual and tactile experience.

A Treatise Concerning the Principles of Human Knowledge (1710), published at twenty-five, presented his full metaphysical system. Berkeley argued that Locke's distinction between primary qualities (really in objects) and secondary qualities (in the perceiver) is untenable — all qualities are equally mind-dependent. The very concept of matter existing independently of perception is incoherent: to conceive of an unperceived tree is already to perceive it in imagination. Only spirits (active, perceiving substances) and ideas (passive, perceived entities) exist.

Three Dialogues between Hylas and Philonous (1713) restated the argument in accessible dialogue form, addressing common objections with charm and philosophical acuity.

Travels and Projects

Berkeley spent much of the 1710s traveling in Europe as chaplain and tutor. In 1724, he conceived an ambitious plan to establish a college in Bermuda for the education of both colonial settlers and indigenous peoples. He received a royal charter and a parliamentary promise of £20,000, sailed to Rhode Island in 1728, and waited three years for the funds — which never came. He returned to London in 1731, donating his Rhode Island farm and library to Yale College.

Later Career and Writings

In 1734, Berkeley was appointed Bishop of Cloyne in County Cork, Ireland, a position he held for eighteen years. His later philosophical work, Siris (1744), was an eccentric meditation that began with the medicinal virtues of tar-water (pine resin dissolved in water) and ascended through chemistry and natural philosophy to Neoplatonic metaphysics.

Alciphron, or the Minute Philosopher (1732) was a series of dialogues defending Christianity against freethinkers. The Analyst (1734) was a brilliant critique of the logical foundations of Newton's calculus, pointing out that the notion of 'infinitesimals' was no more intelligible than the mysteries of theology — a challenge that eventually contributed to the rigorous reformulation of calculus in the 19th century.

Death and Legacy

Berkeley moved to Oxford in 1752 to supervise his son's education and died there on January 14, 1753. The city of Berkeley, California (home of the University of California), is named in his honor, inspired by his poem 'On the Prospect of Planting Arts and Learning in America.'

Berkeley's idealism was mocked by Samuel Johnson, who famously kicked a stone and declared 'I refute it thus!' — missing Berkeley's point entirely. In reality, Berkeley's arguments against material substance are far more rigorous than commonly supposed and have influenced phenomenalism, logical positivism, and contemporary debates in the philosophy of perception.