George Berkeley (1685–1753) was an Irish philosopher and Anglican bishop whose work made significant contributions to early modern empiricism and the philosophy of perception. Educated at Trinity College Dublin, Berkeley became an influential figure in eighteenth-century thought through his critique of materialism and his development of immaterialism, later known as subjective idealism. His central philosophical claim, articulated in A Treatise Concerning the Principles of Human Knowledge (1710) and Three Dialogues between Hylas and Philonous (1713), is that physical objects do not exist independently of perception. According to Berkeley, to be is to be perceived (esse est percipi).
Berkeley argued that what we call physical objects are collections of ideas presented to the mind through sensory experience. He rejected the existence of mind-independent matter, contending that the concept is unintelligible and unnecessary. Instead, he posited that all experiences are produced by God, who ensures the order and consistency of the world. For Berkeley, this view preserved the certainty of empirical knowledge while eliminating the skeptical problems associated with representational theories of perception.
His immaterialism also had theological motivations. Berkeley believed that denying matter safeguarded the existence of God and countered what he saw as atheistic implications of contemporary scientific theories. His philosophy challenged the mechanistic worldview of thinkers such as John Locke and the proponents of Newtonian physics, although he supported Newton’s mathematics and opposed only certain metaphysical interpretations.
Beyond metaphysics, Berkeley wrote on vision, criticizing the view that we perceive distance directly and arguing instead that visual perceptions must be learned through association with touch. His Essay Towards a New Theory of Vision (1709) became a foundational text in the psychology of perception.
Berkeley later served as Bishop of Cloyne and remained active in educational and political matters. Although initially met with resistance, his idealist philosophy has had enduring influence, shaping later work in empiricism, phenomenology, and analytic philosophy.