Berkeley

Central Problem

Berkeley confronts a profound epistemological and metaphysical problem: how can we justify belief in an external material world if all we ever directly perceive are our own ideas? Building on Locke’s empiricist premise that knowledge consists only of ideas, Berkeley asks whether the concept of “matter” or “material substance” existing independently of mind is coherent or even meaningful.

The problem has both philosophical and religious dimensions. Philosophically, if Locke is right that we only know ideas, how can we claim knowledge of material objects “behind” or “causing” those ideas? The gap between idea and thing seems unbridgeable. Religiously, Berkeley sees materialism as the philosophical foundation of atheism—if matter can explain everything, God becomes superfluous. The challenge is to defend both the reality of our knowledge and the existence of God against materialist skepticism.

Berkeley also addresses the problem of abstract ideas inherited from Locke. Can we truly form a general idea of “triangle” or “man” that has no particular characteristics? Berkeley argues such abstraction is psychologically impossible and philosophically unnecessary, leading to his radical nominalism.

Main Thesis

Berkeley’s revolutionary thesis is summarized in the formula esse est percipi—“to be is to be perceived.” For ideas, existence consists entirely in being perceived by a mind. Since what we call “things” are nothing but collections of ideas (a cherry is just the collection of ideas: red, round, sweet, etc.), things too exist only insofar as they are perceived. There is no material substance underlying or causing our perceptions.

Radical Nominalism: Abstract general ideas are impossible. We cannot form an idea of “extension” that has no particular size, shape, or color. What Locke called “general ideas” are actually particular ideas used as signs to represent other similar particulars. A particular triangle in a proof represents all triangles not because it lacks specific characteristics, but because those characteristics are irrelevant to the demonstration.

Immaterialism: Material substance does not exist. Berkeley’s arguments:

1. We only ever perceive ideas, never matter itself
2. Ideas cannot resemble anything except other ideas—a color cannot resemble something invisible
3. Primary qualities (extension, motion) cannot exist without secondary qualities (color, smell)—there is no colorless extension
4. The concept of a material substratum “supporting” qualities is unintelligible
5. Matter, being inert, cannot be the cause of our ideas

Spiritual Causation: Since ideas are passive and require a cause, and matter cannot be that cause, the source must be spirit. Our own minds produce ideas of imagination, but the vivid, orderly, involuntary ideas of sense perception must come from another Spirit—God. The “laws of nature” are simply the regular patterns by which God produces ideas in us.

Preservation of Reality: Things continue to exist when unperceived by finite minds because they are always perceived by God’s infinite mind. Nature is God’s language, speaking to us through the orderly succession of sensible ideas.

Historical Context

Berkeley (1685-1753) developed his philosophy in early eighteenth-century Ireland and England, during a period of intense debate between religious orthodoxy and emerging Deism and free-thinking. Born in Kilkenny, Ireland, he studied at Trinity College Dublin and formulated his core philosophical position—immaterialism—remarkably early, publishing his main works before age 30.

The intellectual context was shaped by Locke’s Essay Concerning Human Understanding (1690), which Berkeley both built upon and criticized. Locke’s empiricism seemed to many to lead toward skepticism about the external world—if we only know ideas, how can we know things? Berkeley’s radical solution was to eliminate the problem by eliminating matter.

Berkeley was also responding to the perceived threat of materialist philosophy, which he associated with Hobbes and with the “free-thinkers” of his day. He saw materialism as leading inevitably to atheism, fatalism, and the denial of providence, free will, and immortality. His immaterialism was explicitly intended as an apologetic for Christian theism.

His later career included an ambitious (ultimately unsuccessful) project to establish a college in Bermuda to educate colonists and Native Americans. As Bishop of Cloyne (from 1734), he devoted himself to philanthropy and practical concerns, including promoting tar-water as a medicinal cure-all. His later work Siris (1744) developed a more explicitly Neoplatonic metaphysics.

Philosophical Lineage

flowchart TD
    Plato --> Neoplatonism
    Neoplatonism --> Berkeley
    Descartes --> Malebranche
    Malebranche --> Berkeley
    Locke --> Berkeley
    Ockham --> Locke
    Locke --> Hume
    Berkeley --> Hume
    Berkeley --> Kant
    Berkeley --> Phenomenalism

    class Plato,Neoplatonism,Descartes,Malebranche,Locke,Ockham,Berkeley,Hume,Kant,Phenomenalism internal-link;

Key Thinkers

Thinker	Dates	Movement	Main Work	Core Concept
Berkeley	1685-1753	British Empiricism	Treatise Concerning the Principles of Human Knowledge	Esse est percipi, immaterialism
Locke	1632-1704	British Empiricism	Essay Concerning Human Understanding	Ideas from experience, primary/secondary qualities
Malebranche	1638-1715	Occasionalism	The Search After Truth	Vision in God, occasionalism
Descartes	1596-1650	Rationalism	Meditations	Mind-body dualism, material substance
Hume	1711-1776	British Empiricism	Treatise of Human Nature	Skepticism about substance, causation

Key Concepts

Concept	Definition	Related to
Esse est percipi	”To be is to be perceived”—for ideas, existence consists in being perceived by a mind	Berkeley, Idealism
Immaterialism	The doctrine that material substance does not exist; only minds and ideas are real	Berkeley, Idealism
Radical nominalism	General ideas are impossible; particular ideas serve as signs for groups of similar particulars	Berkeley, Ockham
Ideas	The immediate objects of perception and thought; passive entities requiring a perceiving mind	Berkeley, Locke
Spirit	Active, perceiving substance; minds that have ideas and exercise will, imagination, memory	Berkeley, Metaphysics
Primary qualities	Extension, figure, motion—Berkeley denies these exist independently of perception	Locke, Berkeley
Secondary qualities	Colors, sounds, tastes—Locke admitted these are mind-dependent; Berkeley extends this to all qualities	Locke, Berkeley
Laws of nature	The fixed, regular patterns by which God produces sensible ideas in finite minds	Berkeley, Theology
Divine language	Nature understood as God’s communication to humans through orderly sensible ideas	Berkeley, Theology
Notions	Knowledge of spirits (one’s own and others’), which differs from knowledge of ideas	Berkeley, Epistemology

Authors Comparison

Theme	Berkeley	Locke	Malebranche
Objects of knowledge	Ideas only	Ideas representing external things	Ideas in God’s mind
Material substance	Does not exist	Exists but unknowable in itself	Exists, created by God
Primary/secondary qualities	No distinction—all mind-dependent	Primary objective, secondary subjective	All qualities perceived in God
Cause of sensory ideas	God (infinite Spirit)	External material objects	God (occasionalism)
Abstract ideas	Impossible	Possible through abstraction	Possible
Universals	Nominalism—particular ideas as signs	Nominalism—ideas as signs	Ideas in divine understanding
Purpose of philosophy	Defense of religion	Extension of natural knowledge	Union with God
Existence of things unperceived	Perceived by God	Exist independently	Exist in God’s ideas

Influences & Connections

• Predecessors: Berkeley ← influenced by ← Locke (empiricism, ideas as objects), Descartes (method of ideas)
• Predecessors: Berkeley ← influenced by ← Malebranche (occasionalism, vision in God), Ockham (nominalism)
• Contemporaries: Berkeley ↔ dialogue with ↔ English Deists (polemic in Alciphron)
• Followers: Berkeley → influenced → Hume (skepticism about substance), Kant (idealism critique)
• Followers: Berkeley → influenced → Phenomenalism, Logical Positivism (verification principle)
• Opposing views: Berkeley ← criticized by ← Johnson (kicking stone refutation), Reid (common sense realism)

Summary Formulas

• Berkeley: To be is to be perceived (esse est percipi); matter does not exist, only minds and their ideas; God is the infinite Spirit who causes our sensible ideas and guarantees their continuous existence.
• Locke: We know only ideas, but these represent external material objects whose primary qualities truly exist in things themselves.
• Malebranche: We see all things in God; matter exists but is causally inert, with God being the only true cause of all effects.
• Hume: Taking empiricism to its logical conclusion, we have no justified belief in either material or spiritual substance.

Timeline

Year	Event
1685	Berkeley born at Dysert, Ireland
1707	Berkeley graduates from Trinity College Dublin
1709	Berkeley publishes Essay Towards a New Theory of Vision
1710	Berkeley publishes Treatise Concerning the Principles of Human Knowledge
1713	Berkeley publishes Three Dialogues between Hylas and Philonous
1728	Berkeley sails for America to establish college in Bermuda
1731	Berkeley returns to England after Bermuda project fails
1732	Berkeley publishes Alciphron (apology against free-thinkers)
1734	Berkeley appointed Bishop of Cloyne, Ireland
1744	Berkeley publishes Siris (tar-water and Neoplatonic metaphysics)
1752	Berkeley moves to Oxford
1753	Berkeley dies at Oxford

Notable Quotes

“The esse of things is percipi, and it is not possible that they should have any existence outside the minds that perceive them.” — Berkeley

“All the choir of heaven and furniture of the earth, in a word all those bodies which compose the mighty frame of the world, have not any subsistence without a mind.” — Berkeley

“Some truths there are so near and obvious to the mind that a man need only open his eyes to see them. Such I take this important one to be, namely, that all the choir of heaven and furniture of the earth have no subsistence without a mind.” — Berkeley

---

NOTE

This summary has been created to present the key points from the source text, which was automatically extracted using LLM. Please note that the summary may contain errors. It serves as an essential starting point for study and reference purposes.