Berkeley’s Immaterialist Idealism

Philosopher Bishop George Berkeley’s theory of consciousness, given his overarching immaterialist idealism, holds that phenomenal consciousness consists in the immediate apprehension of ideas by active finite spirits, that objects of the senses are stable collections of such ideas rather than mind-independent material substances, and that the order, vividness, and public coherence of experience are secured by God as the infinite spirit who causes and sustains the sensory world (Berkeley, 1709, 1710/1734, 1713/1734; Winkler, 1989; Stoneham, 2002).

In other words, nothing exists but minds and the ideas they perceive, that the world we sense is constituted by the qualitative contents of perception themselves rather than by any mind-independent matter lying beneath them, and that these passive, perceived, lawfully ordered ideas are sustained as a coherent public world by the perception and will of an infinite spirit, God. This means that phenomenal experience is not an appearance of reality but manifests its very fabric, with active perceiving spirits as the only other ontological category (Berkeley, 1710, 1713; Downing, 2011).

Berkeley is not a theorist of consciousness in the contemporary scientific sense. His contribution is metaphysical and phenomenological: he relocates what we perceive as reality inside the domain of consciousness while preserving the objectivity of ordinary experience through divine causation and lawlike regularity.

Ideas, Spirits, and the Phenomenal

Berkeley starts with phenomenology. What is immediately present to consciousness are ideas: colors, sounds, tastes, tactile qualities, pains, pleasures, passions, memories, imaginings, and thoughts. In A Treatise Concerning the Principles of Human Knowledge, he argues that the objects of human knowledge are ideas either imprinted on the senses, perceived by reflection on the operations of mind, or formed by memory and imagination (Berkeley, 1710/1734). He does not deny ordinary objects; rather, they are reconceived. An apple, for example, is not an unknowable material substance lying behind experience, but an ordered cluster of visual, tactile, olfactory, gustatory, and affective ideas habitually conjoined and named as one thing.

Thus, Berkeley’s slogan esse est percipi aut percipere—to be is to be perceived or to perceive—means that the ground of being of the things of perception is their being presented in consciousness, while the being of spirits is their active capacity to perceive and to will (Berkeley, 1710/1734; Downing, 2011). Phenomenal consciousness is therefore not an inner representation interposed between mind and world. It is the mode in which the sensible world itself exists.

Anti-Materialism and the Likeness Principle

Berkeley’s theory is directed against representationalist materialism, especially versions he associates with Locke and Cartesian dualism. On the representationalist view, we immediately perceive ideas, but those ideas represent external material objects that exist independently of being perceived. Berkeley’s “likeness principle” denies the intelligibility of this relation: an idea can resemble only another idea, not an unperceived, nonmental substance (Berkeley, 1710/1734; Winkler, 1989). The phenomenal redness, warmth, hardness, sweetness, or spatial contour of an object cannot be copied from matter conceived as intrinsically nonexperiential.

The point is not merely epistemological. Berkeley is not simply saying that we cannot know matter; he argues that the notion of matter as a support of sense qualities is explanatorily empty. If material substance is by definition not colored, sounded, tasted, felt, or otherwise experienced, then it cannot clarify the phenomenal character of experience. Nor can inert extension explain why consciousness contains ordered sensory qualities. Matter, according to Berkeley, becomes a surplus metaphysical category, introduced to explain experience but incapable of doing so.

Perception, Space, and the Primary-Secondary Quality Distinction

Berkeley’s attack on materialism includes a critique of the distinction between primary and secondary qualities. Materialists often conceded that colors, tastes, sounds, heat, and pain are mind-dependent, while preserving extension, figure, motion, solidity, and number as mind-independent features of matter. Berkeley argues that this division cannot be maintained. Primary qualities vary with perspective, bodily constitution, scale, sensory apparatus, and perceptual context no less than secondary qualities. Size can appear large or small, motion fast or slow, shape regular or distorted, depending on the perceiver and conditions of observation (Berkeley, 1713/1734).

His New Theory of Vision gives this critique a phenomenological form. Visual distance, magnitude, and spatial layout are not immediately seen as geometrical properties. They are learned through correlations between visual signs and tactile or kinesthetic ideas (Berkeley, 1709). Vision is semiotic rather than geometrically transparent: visible appearances suggest possible tactile experiences because the mind has learned their regular or lawful conjunction. Phenomenal space is therefore not the passive reception of independently extended matter; it is an ordered field of sensory ideas, cross-modally calibrated and integrated through experience.

God, Objectivity, and the Public World

Berkeley’s idealism is often misread as solipsistic, but his system is designed to avoid solipsism. Finite minds do not create the sensory world. The crucial difference between imagination and perception is that sensory ideas are involuntary, vivid, coherent, stable, and publicly coordinated. I can imagine a tree faintly and intermittently, but the tree I perceive appears with force, detail, resistance, and lawful connection to other possible experiences.

Because ideas are passive and cannot cause one another, and because finite spirits do not cause most sensory ideas by volition, Berkeley infers an infinite spirit—God—as their source (Berkeley, 1710/1734, 1713/1734). God is not a traditional or ritualistic theological addition but the metaphysical ground of objective phenomenal order. Sensible objects continue to exist when no finite human perceives them because they remain within divine perception and causal governance. Thus, Berkeley preserves empirical realism at the level of ordinary life while denying metaphysical realism about matter.

Berkeley's purpose is apologetic, and he says so. The full title of the Principles advertises an inquiry into the grounds of skepticism, atheism, and irreligion, and Berkeley held that materialism was their common source: a mind-independent, self-sufficient matter makes God explanatorily idle, and an unknowable substance behind our ideas makes skepticism unanswerable. Immaterialism dissolves both at once. If nothing exists but minds and their ideas, there is no veil to be skeptical about, and no candidate for a godless self-running nature. The doctrine that appears most extravagant is thus the one Berkeley took to be most protective of ordinary belief, and he described his project as directed to practice and morality, beginning with making manifest the nearness and omnipresence of God (Berkeley, 1710/1734).

The later work makes the theological function explicit. In Alciphron, Berkeley recasts his theory of vision as a proof: the objects of sight constitute a divine visual language, a system of arbitrary signs bearing no resemblance or necessary connection to the tangible things they signify, learned as one learns a tongue. Because such a language cannot be accounted for by mechanical principles, by atoms, or by chance, its regular and instructive operation testifies to the immediate presence of a spirit (Berkeley, 1732, IV.7–14; Kline, 1987). This reframes the New Theory of Vision retrospectively. The cross-modal calibration described earlier in this entry as a phenomenological finding is, for the mature Berkeley, evidence of a speaker. He said as much in publishing the two works together, holding that the theory of vision affords thinking men a new proof of the existence and immediate operation of God (Berkeley, 1733).

Active Subjectivity and Assessment

Berkeley’s active subject of consciousness is a spirit, mind, soul, or self. This creates an explanatory asymmetry. Ideas are passive objects of awareness; spirits are active perceivers and agents. A spirit is not itself an idea, because anything perceived as an idea is passive, determinate, and object-like. The self is known not by sensory presentation but by reflective “notion” of its own perceiving and willing (Berkeley, 1710/1734; Flage, 2024). This is one of the least developed but philosophically crucial parts of Berkeley’s theory: he must explain how active minds are known if all immediate objects of knowledge are ideas.

As a theory of phenomenal consciousness, Berkeley’s idealism is strongest as an anti-materialist account of the immediacy, qualitative character, and mind-dependence of sensory experience. It denies that consciousness is a veil hiding reality; instead, phenomenal consciousness is where sensory reality is directly present. Its principal vulnerabilities are also clear: divine causation carries much of the explanatory burden; the ontology of active spirits is less accessible than the ontology of ideas; and the identification of ordinary objects with idea-collections remains difficult to reconcile with contemporary scientific realism. Nonetheless, Berkeley remains a major historical model of consciousness-first metaphysics: reality is not fundamentally matter plus consciousness, but active spirit and ordered experience.

References

Berkeley, G. (1709). An Essay Towards a New Theory of Vision. Dublin: Aaron Rhames.

Berkeley, G. (1710/1734). A Treatise Concerning the Principles of Human Knowledge. 2nd ed. London: Jacob Tonson.

Berkeley, G. (1713/1734). Three Dialogues Between Hylas and Philonous. 2nd ed. London: Jacob Tonson.

Berkeley, G. (1732). Alciphron, or the Minute Philosopher. London: J. Tonson.

Berkeley, G. (1733). The Theory of Vision, or Visual Language... Vindicated and Explained. London: J. Tonson.

Berkeley, G. (1744). Siris: A Chain of Philosophical Reflexions and Inquiries. Dublin: Margt. Rhames.

Downing, L. (2011). George Berkeley. In E. N. Zalta (Ed.), The Stanford Encyclopedia of Philosophy.

Flage, D. E. (2024). George Berkeley. Internet Encyclopedia of Philosophy.

Kline, A. D. (1987). Berkeley's divine language argument. In E. Sosa (Ed.), Essays on the Philosophy of George Berkeley (pp. 129–142). Dordrecht: Reidel.

Pitcher, G. (1977). Berkeley. London: Routledge & Kegan Paul.

Stoneham, T. (2002). Berkeley’s World: An Examination of the Three Dialogues. Oxford: Oxford University Press.

Winkler, K. P. (1989). Berkeley: An Interpretation. Oxford: Clarendon Press.