The Philosophy of George Berkeley

George Berkeley’s (1685–1753 ce) most lasting philosophical legacies are his immaterialism – the denial of the existence of matter – and his idealism, the positive doctrine that reality is constituted by spirits and their ideas. This is as Berkeley would have wanted it; he clearly viewed the thesis that esse est percipi aut percipere (to be is to be perceived or to perceive) as his central philosophical insight, one which would revolutionize philosophy. However, he would be dismayed, if not surprised, to see the extent to which his idealistic system is still commonly regarded as unacceptably counterintuitive. Berkeley was in his own lifetime often dismissed as a skeptical purveyor of paradoxes. Nothing could have been further from his intentions; Berkeley saw his idealism as being reconcilable with common sense and, more importantly, as providing a weapon against both skepticism and atheism. To understand the significance of immaterialism/idealism for Berkeley, it is necessary to fill in more of his historical context.


Berkeley was born in 1685 near Kilkenny, Ireland. After several years of schooling at Kilkenny College, he entered Trinity College, in Dublin, at age 15. He was made a fellow of Trinity College in 1707 (three years after graduating) and was ordained in the Anglican Church shortly thereafter. At Trinity, where the curriculum was notably modern, Berkeley encountered the new science and philosophy of the late seventeenth century, which was characterized by its hostility towards Aristotelianism. Berkeley, however, was never satisfied for long with any received opinions, no matter how up to date; he immediately began to exercise his sharp critical faculties on the works of Descartes, Locke, Malebranche, Newton, Hobbes, and others. Berkeley’s self-description here is revealing:

one thing I know, I am not guilty of. I do not pin my faith on the sleeve of any great man. I act not out of prejudice & prepossession. I do not adhere to any opinion because it is an old one, a receiv’d one, a fashionable one, or one that I have spent much time in the study and cultivation of. (Philosophical Commentaries, entry 465)

Berkeley’s philosophical notebooks, which he began in 1707 and did not intend for publication, are often styled the Philosophical Commentaries because of the fact that many of the entries record his responses to other philosophical texts. The Commentaries provide rich documentation of Berkeley’s philosophical evolution, enabling the reader to track the emergence of his immaterialist philosophy from a critical response to, most crucially, Locke, Descartes, and the Cartesians.

Berkeley saw Locke and the Cartesians as sharing a commitment to a general picture (with particular qualifications in each case) which we might call representative mechanist materialism. According to this view, there are two sort of beings in the world, spiritual beings (minds) and material beings (bodies). Material beings are mind-independent and conceived mechanistically, as composed of submicroscopic particles fully characterizable in terms of a strictly limited number of (primary) qualities: size, shape, motion/rest, and perhaps solidity. Other apparent (secondary) qualities (color, taste, sound) are not intrinsic qualities of bodies themselves, but are explained in terms of the effects that bodies have on perceivers. In perception, the immediate object of awareness is an idea, a mind-dependent item. However, the sensory idea represents a mind-independent material object to us, thus allowing us to (mediately) perceive the material object which caused that idea.

Berkeley regarded representative mechanist materialism as pernicious in that it was conducive to atheism and led immediately to skepticism. In its commitment to matter, it allowed the existence of something mind-independent, and something which might be thought to be God-independent as well, thus laying the groundwork for the denial of the existence of a Christian God. Although, of course, God does play an important role in the philosophies of Descartes, Malebranche, and Locke, Berkeley no doubt believed that he saw the consequences of materialism in Hobbes and Spinoza, the “notorious infidels” of the seventeenth century. The tendency to skepticism is perhaps more compelling to the modern reader: the primary/secondary quality distinction entails that our senses systematically mislead us; we mistakenly think that the apple is red in just the way it appears to us to be, while redness in the apple is merely a power derived from a particular arrangement of uncolored particles which allows the apple to cause us to have an idea of red. Still more seriously, representationalism seems to open up the possibility of still more grave deception; if we only have immediate access to ideas, what grounds do we have to suppose that they are representative of reality at all? Berkeley saw a strikingly simple solution to these difficulties: abandon matter and construct a metaphysical system from spirits (minds) and their ideas:

matter or the absolute existence of corporeal objects, hath been shewn to be that wherein the most avowed and pernicious enemies of all knowledge, whether human or divine, have ever placed their chief strength and con- fidence. And surely, if by distinguishing the real existence of unthinking things from their being perceived, and allowing them a subsistence of their own out of the minds of spirits, no one thing is explained in Nature; but on the contrary a great many inexplicable difficulties arise: if the supposition of matter is barely precarious, as not being grounded on so much as one single reason: . . . if withal the removal of this matter be not attended with the least evil consequence, if it be not even missed in the world, but everything as well, nay much easier conceived without it: if lastly, both skeptics and atheists are for ever silenced upon supposing only spirits and ideas, and this scheme of things is perfectly agreeable both to reason and religion: methinks we may expect it should be admitted and firmly embraced. (Principles, section 133)

Berkeley provided an initial glimpse of his mature metaphysics in his first important published work, An Essay Towards a New Theory of Vision. Most obviously, Berkeley intended this work to address an ongoing debate on the question of how distance is perceived by sight, and indeed the New Theory became an influential work in the psychology of vision. Berkeley also, however, sought to establish a conclusion that is directly relevant to his idealism: that the objects of sight and touch are heterogeneous. Berkeley argues that what we see is something ideal, minddependent, quite distinct from what we touch (New Theory, sections 43–50). Interestingly, he leaves in place the assumption that the objects of touch are mind-independent material objects; he tells us elsewhere that it was beside his purpose to refute this “vulgar error” in a work on vision (Principles, section 44).

By 1710, however, Berkeley was prepared to propose and defend his full idealistic system. In the Treatise Concerning the Principles of Human Knowledge (1710) and the Three Dialogues between Hylas and Philonous (1713), Berkeley lays out his two-sided case for idealism. On the one hand, he conducts a negative campaign designed to demonstrate the incoherence of materialism; on the other, he seeks to show positively the workability of his idealist system. Both the positive and negative programs, while not ultimately conclusive, are compelling and continue to reward detailed philosophical scrutiny.

The main body of the Principles opens with a strikingly simple “refutation” of materialism which takes the following form (see Principles, section 4):

  1. We perceive ordinary physical objects.
  2. We perceive only ideas/sensations.
  3.  Therefore, ordinary objects are ideas/sensations.

Of course, the representative mechanist materialist would respond to this argument by introducing a distinction between mediate and immediate perception, noting that on his view ordinary objects are perceived mediately, while we immediately perceive only ideas, thus avoiding the conclusion. In effect, Berkeley devotes much of the rest of the Principles to pointed criticism of the sort of representationalism that permits this response. Most importantly, he argues that because an idea can only be like another idea, we cannot suppose that ideas represent material objects by resemblance. Nor can the thesis that ideas represent material objects in virtue of being caused by them be defended, since “they [the materialists] own themselves unable to comprehend in what manner body can act upon spirit, or how it is possible it should imprint any idea in the mind” (Principles, section 19).

In addition, Berkeley devotes the introduction to the Principles to an influential attack on Lockean abstract ideas, arguing that abstract, general ideas cannot be formed in the way Locke sometimes seems to suggest, by stripping away particularizing features of ideas of particulars, leaving an intrinsically general idea. Rather, in Berkeley’s view, what serve us for general ideas are simply ordinary ideas of particulars, used in a general way. Berkeley saw his anti-abstractionism as fueling his attack on materialism, for he held that we cannot abstract ideas of shape from ideas of color in the way that the materialists’ primary/secondary quality distinction seems to require, nor can we “distinguish [i.e. abstract] the existence of sensible objects from their being perceived, so as to conceive them existing unperceived” (Principles, section 5).

Berkeley’s positive program is for the most part concerned with showing that, despite the absence of matter, according to his view “there is a reality, there are things, there is a rerum Natura” (Philosophical Commentaries, entry 305). Berkeley’s reality is constituted by spirits and their ideas. Physical things, or bodies, are congeries of ideas. The order of nature consists in the regularities amongst our ideas, and is guaranteed by the goodness of God (himself a spirit), who causes our ideas of sense. Thus the scientist (or natural philosopher, in Berkeley’s day) studies the order of ideas, the grammar of nature. A distinction between real things and imaginary ones (chimeras) can be made in terms of the vividness and orderliness of the ideas which constitute real things. Berkeley’s system is heavily dependent on God for its workability, but it is worth noting that Berkeley and his contemporaries would have counted this as a virtue of the theory, rather than a defect. Idealism exhibits our dependence, as finite minds, on the infinite mind, and coheres beautifully with the oft-quoted biblical phrase, “in him we live and move and have our being.”

Despite Berkeley’s acutely critical response to Locke and the Cartesians, his most profound intellectual debts are clearly to them. In particular, Berkeley’s emphasis on the centrality of sensory experience in knowledge acquisition is strongly shaped by Locke and has led to his being grouped with Locke and Hume under the rubric of “British Empiricism.” This classification, however, should not be permitted to obscure the considerable influence of Descartes and, especially, Malebranche on his thought.

Berkeley was dismayed by the reception of his immaterialist philosophy, and in fact composed the Dialogues in an effort to gain a broader audience for his views. His disappointment, however, did not discourage him from further philosophical work. In 1720, while completing a fouryear tour of Europe as tutor to a young man, George Ashe, Berkeley composed De Motu, a tract on the philosophical foundations of mechanics. In this essay, he critiques the dynamic (force-based) physical theories of his time, particularly Leibniz’s and Newton’s, and develops and elaborates his philosophy of science. In doing so, he highlights some of the philosophical sources of resistance to Newtonianism and proposes an intriguing solution: an instrumentalist interpretation of Newton’s theory as an excellent calculating device, the use of which should not be thought to commit us to the existence of forces.

After his continental tour, Berkeley returned to Ireland and resumed his position at Trinity until 1724, when he was appointed Dean of Derry. At this time, Berkeley began developing his scheme for founding a college in Bermuda. He was convinced that Europe was in moral and spiritual decay, and that the New World offered hope for a new golden age. Having secured a charter and promises of funding from the British Parliament, Berkeley set sail for America in 1728, with his new bride, Anne Forster. They spent three years in Newport, Rhode Island, awaiting the promised money, but Berkeley’s political support had collapsed and they were forced to abandon the project and return to Britain in 1731. While in America, Berkeley composed Alciphron, a work of Christian apologetics directed against the “freethinkers” whom he took to be enemies of established Anglicanism. Alciphron is, however, also very much a philosophical work, and is a crucial source of Berkeley’s views on language, which include an interesting critique of the Lockean semantic thesis that every meaningful word must stand for an idea. Berkeley argues here that the purposes of language include the guiding of action, that this may be accomplished without each word suggesting an idea, and that language which successfully guides action is thereby meaningful.

Shortly after returning to London, Berkeley composed the Theory of Vision, Vindicated and Explained, a defense of his earlier work on vision against a published attack, and the Analyst, an acute and influential critique of the foundations of Newton’s calculus. In 1734 he was made Bishop of Cloyne, and thus he returned to Ireland. It was here that Berkeley wrote his last, strangest, and best-selling (in his own lifetime) philosophical work. Siris (1744) has a threefold aim: to establish the virtues of tar-water (a liquid prepared by letting pine tar stand in water) as a medical panacea, to provide scientific background supporting the efficacy of tar-water, and to lead the mind of the reader, via gradual steps, toward contemplation of God. Although Berkeley retains the basics of his idealism in Siris, neo-Platonic influences produce a work of a very different tone from that of the Principles and Dialogues. Nevertheless, Siris remains a crucial source for understanding Berkeley’s attitude toward the natural philosophy of his day.

Berkeley died in 1753, shortly after moving to Oxford to supervise the education of his son George, one of the three out of seven of his children to survive childhood. Despite the mostly uncomprehending response accorded to his metaphysical views by his contemporaries, his influence on Hume and Kant was considerable, his critique of his predecessors continues to shape our understanding of them, and his idealism is one of the enduring positions on the map of Western philosophy.

Further reading

The Philosophy of Baruch Spinoza

Atherton, Margaret: Berkeley’s Revolution in Vision (Ithaca, NY: Cornell University Press, 1990).
Berman, David: George Berkeley: Idealism and the Man (Oxford: Clarendon Press, 1994).
Jesseph, Douglas M.: Berkeley’s Philosophy of Mathematics (Chicago: University of Chicago Press, 1993).
Pitcher, George: Berkeley (London: Routledge and Kegan Paul, 1977).
Tipton, I. C.: Berkeley: The Philosophy of Immaterialism (London: Methuen, 1974).
Urmson, J. O.: Berkeley (Oxford: Oxford University Press, 1982).
Winkler, Kenneth P.: Berkeley: An Interpretation (Oxford: Oxford University Press, 1989).


Philosophical Commentaries (1707–8), in Philosophical Works, ed. Michael Ayers (London: Dent, 1975).
An Essay towards a New Theory of Vision (Dublin, 1709), in Philosophical Works, ed. Michael Ayers (London: Dent, 1975).
A Treatise concerning the Principles of Human Knowledge (Dublin, 1710), in Philosophical Works, ed. Michael Ayers (London: Dent, 1975).
Three Dialogues between Hylas and Philonous (London, 1713), in Philosophical Works, ed. Michael Ayers (London: Dent, 1975). De Motu (London, 1721), in “De Motu” and “The Analyst”: A Modern Edition with Introductions and Commentary, trans. and ed. Douglas M. Jesseph (Dordrecht: Kluwer Academic Publishers, 1992).
Alciphron: or the Minute Philosopher (London, 1732), in The Works of George Berkeley, Bishop of Cloyne, volume 3, ed. A. A. Luce and T. E. Jessop (London: Thomas Nelson and Sons, 1948–57).
The Analyst (Dublin and London, 1734), in “De Motu” and “The Analyst”: A Modern Edition with Introductions and Commentary, trans. and ed. Douglas M. Jesseph (Dordrecht: Kluwer Academic Publishers, 1992).
Siris: A Chain of Philosophical Reflections and Enquiries Concerning the Virtues of Tar-water (Dublin and London, 1744), in The Works of George Berkeley, Bishop of Cloyne, volume 5, ed. A. A. Luce and T. E. Jessop (London: Thomas Nelson and Sons, 1948–57).

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