George Berkeley, Anglo-Irish philosopher and author (b. 1685)

George Berkeley: The Architect of Immaterialism and Subjective Idealism

George Berkeley (12 March 1685 – 14 January 1753), widely recognized as Bishop Berkeley due to his significant ecclesiastical role as the Anglican Bishop of Cloyne in the Church of Ireland, was a seminal Irish philosopher. His most profound and enduring contribution to Western thought was the development and vigorous advocacy of a revolutionary theory he termed "immaterialism." This philosophical stance was subsequently refined and referred to by others as "subjective idealism."

At the core of Berkeley's immaterialism is a radical denial of the existence of material substance—the idea that objects possess an independent, mind-external reality composed of inert matter. Instead, Berkeley contended that the familiar objects we perceive daily, such as a sturdy table or a comfortable chair, are nothing more than collections of ideas or sensations existing solely within a perceiving mind. Consequently, his famous dictum, "Esse est percipi" (to be is to be perceived), encapsulates the essence of his philosophy: objects cannot exist without being perceived. For Berkeley, their continued existence, even when unobserved by human minds, is guaranteed by their perpetual perception in the infinite, all-encompassing mind of God.

The Critique of Abstraction: A Foundation for Immaterialism

Integral to Berkeley's argument for immaterialism was his meticulous and forceful critique of abstraction. He argued that abstract ideas—concepts that attempt to represent general notions stripped of their particular qualities, such as "man" without specific height or color, or a "triangle" that is neither equilateral, isosceles, nor scalene—are inherently incoherent and impossible to form. Berkeley believed that such abstract ideas lead to philosophical confusion and provide a false basis for the notion of independent material substance. For him, only particular, concrete ideas, as they are perceived, truly exist.

Berkeley's Monumental Works: Shaping Philosophical and Scientific Discourse

An Essay Towards a New Theory of Vision (1709)
Berkeley's first major published work meticulously explored the intricacies and inherent limitations of human vision. In this ground-breaking essay, he advanced the theory that the proper objects of sight are not external, material objects themselves but rather light and color. He argued that our perception of distance and size is not a direct apprehension of external spatial reality but rather an inference based on tactile sensations and customary associations. This work laid the essential epistemological groundwork, foreshadowing his later arguments against the independent existence of material objects by demonstrating the mind-dependent nature of visual perception.
A Treatise Concerning the Principles of Human Knowledge (1710) and Three Dialogues between Hylas and Philonous (1713)
Following the initial, somewhat poor reception of his chief philosophical work, A Treatise Concerning the Principles of Human Knowledge, Berkeley painstakingly rewrote his core arguments in a more accessible and engaging dialogue format. This resulted in the highly influential Three Dialogues between Hylas and Philonous. In this literary masterpiece, Berkeley's profound views are eloquently articulated by the character Philonous (from Greek: "lover of mind"), who systematically refutes the positions of Hylas (from "hyle," Greek for "matter"), a character designed to embody the arguments of Berkeley's philosophical opponents. Notably, Hylas represents key figures like John Locke, whose influential theory of primary and secondary qualities distinguished between objective, mind-independent properties (like extension and solidity) and subjective, mind-dependent ones (like color and taste). Berkeley, through Philonous, meticulously dismantled this distinction, arguing that all qualities, primary and secondary alike, are equally dependent on perception and thus exist only as ideas in the mind.
De Motu (On Motion) (1721)
In this significant Latin treatise, Berkeley critically engaged with Isaac Newton's highly influential doctrines of absolute space, absolute time, and absolute motion. Berkeley argued against the existence of such absolute, unobservable entities, proposing instead a relational theory where motion, space, and time are understood solely in terms of the relationships between bodies and minds. This pioneering relational view served as a remarkable precursor to later developments in physics, particularly the conceptual frameworks advanced by Ernst Mach in the 19th century and Albert Einstein's theory of relativity in the 20th century, both of whom challenged Newtonian absolute frameworks.
Alciphron, or The Minute Philosopher (1732)
This work represents a vigorous Christian apologetic penned by Berkeley, specifically designed to counter the burgeoning influence of "free-thinkers" of his era. These individuals, often deists or atheists, questioned traditional religious doctrines based on reason and empiricism. Berkeley, through a series of dialogues, sought to demonstrate the rational foundations of Christian belief and expose the perceived inconsistencies in the arguments of his philosophical adversaries.
The Analyst; or, A Discourse Addressed to an Infidel Mathematician (1734)
This highly influential work presented a scathing and insightful critique of the logical foundations of calculus, as developed by both Isaac Newton (fluxions) and Gottfried Leibniz (infinitesimals). Berkeley famously challenged the "ghosts of departed quantities"—the infinitely small, yet non-zero, increments that were central to the calculus of his time but lacked rigorous definition. His critique, though controversial, was instrumental in stimulating subsequent generations of mathematicians to develop more robust and rigorous foundations for calculus in the 19th century, ultimately leading to the modern understanding of limits.

Berkeley's Enduring Legacy and 20th-Century Revival

Interest in George Berkeley's philosophical contributions experienced a significant resurgence after World War II. This renewed attention stemmed from the striking relevance of his ideas to many of the paramount philosophical issues that dominated 20th-century thought, particularly within analytic philosophy and phenomenology. His profound discussions on the problems of perception, the intricate relationship between mind and reality, the critical distinction (and Berkeley's dissolution) of primary and secondary qualities, and the profound importance of language in shaping our understanding of the world continue to resonate deeply with contemporary philosophers. Berkeley's work provides essential insights into epistemology (the theory of knowledge) and metaphysics (the nature of reality), making him a foundational figure whose ideas remain highly debated and influential even today.

Frequently Asked Questions About George Berkeley

What is George Berkeley's "immaterialism" in simple terms?
Berkeley's "immaterialism," also known as subjective idealism, is the philosophical view that physical objects do not exist independently of being perceived. Instead, they are collections of ideas or sensations that exist only in the mind. For Berkeley, the very existence of a thing ("to be") is predicated on it being perceived ("is to be perceived").
Did Berkeley deny the existence of a real world?
No, Berkeley did not deny the existence of a real world. He denied the existence of "material substance" as an underlying, unperceived stuff that constitutes reality. He believed the world we perceive—full of colors, sounds, textures—is very real, but it exists as ideas in minds, ultimately sustained by the mind of God, ensuring its consistent and objective reality.
How did Berkeley's philosophy differ from John Locke's?
While both were empiricists, Berkeley directly challenged John Locke's distinction between primary qualities (like shape and size, which Locke believed existed objectively in matter) and secondary qualities (like color and taste, which Locke believed were subjective perceptions). Berkeley argued that all qualities, primary and secondary alike, are equally mind-dependent and exist only as ideas, thus eliminating the need for independent material substance.
What was Berkeley's contribution to mathematics?
In his work The Analyst, Berkeley famously critiqued the logical foundations of calculus, particularly the concepts of infinitesimals used by Newton and Leibniz. Although a critique, it played a crucial role in spurring mathematicians to develop more rigorous and logically sound foundations for calculus in the subsequent centuries, leading to the modern concept of limits.
Why is George Berkeley still relevant today?
Berkeley remains highly relevant because his work delves into fundamental philosophical questions about perception, the nature of reality, the mind-body problem, and the role of language, which continue to be central topics in contemporary philosophy. His ideas paved the way for discussions in epistemology, metaphysics, and the philosophy of mind that are still active areas of inquiry.