Three Dialogues Between Hylas and Philonous Analysis

George Berkeley


(Student Guide to World Philosophy)

In Three Dialogues Between Hylas and Philonous, George Berkeley defends the view that matter does not exist, that the universe contains minds or spirits but no realm of atoms and molecules. Berkeley argues that things that are normally considered material objects—stones, trees, shoes, apples—have no existence outside the minds and experiences of conscious beings. Like an object in a dream, a stone has no existence outside consciousness. If all conscious beings were to stop perceiving some sensible object—the moon, for example—that object would cease to exist. Although Berkeley’s book owes its philosophical greatness to the many important arguments that are presented in support of the main thesis, the work is also notable for the simplicity and clarity with which the ideas are conveyed. The ideas are presented in the form of a dialogue between Hylas, a materialist, and Philonous, the representative of Berkeley’s idealism.

Perception as the Basis of Reality

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The main argument in the work centers on an examination of the set of properties of which sensible objects are composed. Berkeley first examines the properties that philosophers have called “secondary qualities” (heat, taste, sound, smell, color) and argues that these properties have no existence outside sensations and perceptions in the minds of perceivers. He then argues that the same sorts of considerations will show that what have been called the “primary qualities” of sensible objects—extension (length and width), shape, hardness, weight, motion and other characteristics—also have no existence outside the perceptions of conscious beings. In arguing that every property that a sensible object has exists only as a sensation or a property of a sensation within a mind, Berkeley is showing that the entire sensible object has no existence outside the mind. For Berkeley, a cherry is nothing over and above the sensations experienced in connection with it. “Take away the sensations of softness, redness, tartness, and you take away the cherry,” he writes.

Secondary Qualities Exist Only in the Mind

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Berkeley begins his argument by reference to heat. Intense heat, like intense cold, is pain; it is intrinsically unpleasant. Pain, like pleasure, is a kind of experience; it is something that cannot exist outside someone’s consciousness. Therefore, when someone feels intense heat or intense cold, Berkeley reasons, what he feels is in his own mind, not in some inert, unfeeling object existing outside his consciousness. To be aware of intense heat is simply to be aware of a particular kind of pain sensation.

To the objection that intense heat is a cause of pain and not itself literally “pain,” Berkeley replies that when one is perceiving intense heat, the heat of which one is aware is not distinguishable from the pain sensation of which one is aware. In perceiving the heat, the person is not aware of two things, heat and a pain sensation, but of only one thing, a painful sensation.

The temperature that an object appears to have differs under different circumstances, Berkeley proceeds. If one’s left hand is hot and one’s right hand cold and both hands are immersed in a bowl of water, the water seems cool to the left hand and warm to the right hand. From this fact, Berkeley concludes that the heat that one feels cannot be a feature of some object existing outside one’s mind. No single object could have the incompatible properties of warmth and coolness at once. Berkeley concludes that the warmth and coolness that one perceives are sensations within one’s own experience. What one thinks of as the “temperature” of the water is simply the sensation experienced in connection with the water. The sensation is in the consciousness of the person perceiving the temperature, not in an unfeeling object outside one’s consciousness.

These arguments concerning heat can be paralleled for the other secondary qualities of sensible objects. A sweet taste is a form of pleasure; a bitter taste is intrinsically unpleasant or painful. Because pleasure and pain are necessarily mental phenomena, a sweet or bitter taste, because it is a pleasure or pain, must itself be a mental phenomenon, Berkeley reasons. Furthermore, the taste that people perceive in an object varies under different conditions. A food that one finds sweet at one time may seem bitter or tasteless another time. The taste a food has when one is sick differs from its taste when one is well, Berkeley writes. What differs in the two cases, he reasons, is not the alleged external object but the experience had when tasting the food. In each case, one has different taste sensations, and these taste sensations, which are the taste of the food, exist in the mind of the person doing the tasting. Berkeley considers the fact that some people delight in the very food that others find repulsive to be further proof that the taste of a food is not a property inherent in the object that allegedly exists outside people’s minds but a sensation undergone by the people who taste the food. Similar arguments support the claim that odor or...

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Primary Qualities Exist Only in the Mind

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If the existence of perceptual variation is reason to conclude that the secondary qualities do not exist outside minds, Berkeley reasoned, then philosophers have the same reason to conclude that the primary qualities also lack existence outside minds. Like the secondary qualities, the primary qualities give rise to radical perceptual variations. The extension that an object appears to have varies as the object is perceived from different positions, Berkeley explains. The visible extension that a tree has, the extension that it has in relation to the expanse of a perceiver’s field of vision, grows larger as the perceiver approaches the tree and shrinks as the perceiver moves away from the tree. When a perceiver is near, a tree may appear to be a hundred times larger than it does from a great distance. (Imagine how much larger the moon would look if one could see it from a distance of only ten miles.) It does not help to reply that the tree has the same size in feet and inches whatever one’s distance from it, for the visible extension of a foot or an inch itself is not a constant, and it too goes through the same variations as one approaches or recedes from it. A twelve-inch ruler looks large from very close but tiny when perceived from a distance. Furthermore, Berkeley argues, a sensible object may present differing visible extensions at one and the same time. The foot of a mouse, which seems tiny to a person, would seem to be of considerable extension to the mouse. An object that extends over a large portion of the field of vision of a mouse would extend over a small portion of the visual field of a person. Berkeley concludes that the extension of a sensible object is not a property of an object that exists outside consciousness but a property of a sensation in the mind of a perceiver.

The types of considerations which show that the extension of a sensible object has no existence outside a mind also show that shape, hardness, and the other primary qualities are only properties of sensations within the minds of perceivers. The shape, hardness, and motion which an object appears to have also vary from one perceiver to another and vary for a single perceiver when the object is viewed under different conditions.

One might think that the fact that objects are perceived as being at a...

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Reality as Spirit

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If what one considers real objects are like objects in dreams and hallucinations in having no existence outside the mind, how then does Berkeley distinguish the former from the latter? Berkeley explains that the perceptions one considers real are vivid and consistent in a way that those that one does not consider real are not.

What then is the cause of people’s perceptions of sensible objects if not a world of material substance corresponding to those perceptions? Berkeley reasons that because one does not cause or coordinate one’s own sensations, one’s sensations must have a cause outside oneself, and this cause, Berkeley concludes, is an omnipresent infinite Spirit. >From the order, beauty, and design with which one’s sensations appear Berkeley concludes that the designer is wise, powerful, and good “beyond comprehension.”


(Student Guide to World Philosophy)

Additional Reading

Berman, David. Berkeley. New York: Routledge, 1999. An excellent biographical introduction to the thoughts of the philosopher, clearly presented and requiring no special background. Bibliography.

Berman, David. George Berkeley: Idealism and the Man. New York: Oxford University Press, 1994. This worthwhile analysis of George Berkeley’s distinctive philosophical positions focuses on his religious thought. Contains considerable information about Berkeley’s life and his considerable influence.

Bonk, Sigmund. “We See God”: George Berkeley’s Philosophical Theology. New York: Peter Lang, 1997. A good analysis focusing on Berkeley’s spiritual thoughts.

Dancy, Jonathan. Berkeley: An Introduction. New York: Basil Blackwell, 1987. Dancy provides a helpful introduction that is useful for beginning students.

Foster, John, and Howard Robinson, eds. Essays on Berkeley: A Tercentennial Celebration. New York: Oxford University Press, 1985. This collection contains important interpretations of Berkeley’s philosophy by leading scholars in the field.

Jones, W. T. A History of Western Philosophy: Hobbes to Hume. New York: Harcourt, Brace and World, 1969. Offers a clear and accessible introduction to the key theories in Berkeley’s philosophy.

Muehlman, R. G., ed. Berkeley’s Metaphysics: Structural, Interpretive, and Critical Essays. University Park: Pennsylvania University Press, 1995. A good collection of essays that analyze and criticize Berkeley’s metaphysical idealism.

Richie, A. D. George Berkeley: A Reappraisal. Manchester, England: Manchester University Press, 1967. Richie argues that the key to understanding Berkeley is found in his theory of vision.

Turbayne, Colin M. Critical and Interpretive Essays. Minneapolis: University of Minnesota Press, 1982. Turbayne’s essays explore key aspects of Berkeley’s theory of knowledge and metaphysics.

Urmson, J. O. Berkeley. Oxford: Oxford University Press, 1982. A reliable commentary on Berkeley’s thought by an influential twentieth century philosopher.

Warnock, G. J. Berkeley. London: Penguin Books, 1953. This introduction is particularly useful in its account of Berkeley’s views of science, mathematics, and language.