Three Dialogues Between Hylas and Philonous

Quick Facts

• Full title: Three Dialogues Between Hylas and Philonous in Opposition to Sceptics and Atheists
• Author: George Berkeley
• Published: 1713
• Form: three philosophical dialogues
• Main issue: whether matter exists as something outside all minds and perceptions
• Main position: immaterialism, Berkeley's view that ordinary objects are real but are not mind-independent material substances

The Problem

Berkeley is trying to block a kind of skepticism that he thinks modern philosophy accidentally creates.

The target is not tables, trees, apples, or fire. Berkeley thinks those are real. His target is "matter" understood as a hidden material substance that exists behind all experience, supports sensible qualities, and would be there even if no mind perceived it.

Hylas defends that ordinary view. His name comes from the Greek word for matter. Philonous, whose name means lover of mind, speaks for Berkeley. Hylas begins by accusing Philonous of being absurd: surely denying matter is the same as denying the real world. Philonous turns the charge around. He argues that belief in hidden matter makes us less certain of the world, because it says we never directly know things themselves. We know only appearances that may or may not match an unknowable material reality.

So the problem is simple: can we make sense of a world that exists outside all perception, or does that idea add confusion without explaining anything?

In One Minute

Three Dialogues is Berkeley's clearest defense of immaterialism. Immaterialism does not mean "nothing exists." It means there is no mind-independent material substance. Reality contains minds, which perceive and act, and ideas, which are the colors, sounds, shapes, tastes, pains, and other things perceived.

Berkeley's short formula is often put as "to be is to be perceived." For ordinary objects, existing means being available in experience. An apple is not a mysterious material core plus a few appearances. It is the stable collection of sensible qualities we call an apple: red or green color, round shape, smooth feel, smell, taste, and so on.

The dialogues argue that matter, as philosophers define it, is not needed. It cannot be sensed. It cannot explain perception. It cannot be clearly imagined. Berkeley then says stable experience is secured by God, an infinite mind who orders the world and keeps it from being a private dream.

The Main Argument

Philonous starts with what Hylas thinks is obvious: sensible things are what we immediately perceive by the senses. Heat, color, taste, sound, shape, motion, and hardness are examples of sensible qualities.

Then Philonous asks where these qualities exist. Take heat. If one hand is warm and the other is cold, the same water can feel cool to one hand and warm to the other. The water cannot literally have both opposite qualities in itself in the same way. So the felt heat and cold belong to experience. They are ideas in a perceiving mind.

He repeats the pressure with tastes, smells, sounds, colors, and then with so-called primary qualities such as shape, size, motion, and extension. Primary qualities were supposed to belong to matter itself, unlike secondary qualities such as color or taste. Berkeley says the same problem returns. A tower looks small from far away and large up close. A surface looks smooth to the naked eye and rough under a microscope. Size and shape as perceived vary with the perceiver, the sense organ, and the conditions of perception.

Hylas tries to retreat. Maybe what we perceive are only ideas in the mind, but those ideas copy or represent material objects outside the mind. Philonous rejects this too. An idea can resemble only another idea. A color in experience can be like another color in experience, but it is not clear what it would mean for a perceived color to resemble an unperceived material thing that has no color as we experience it.

The final move is about explanation. Hylas thinks matter causes our ideas. Philonous replies that this does not help. If matter is defined as mindless, unperceived stuff, we still do not understand how it produces ideas in a mind. Berkeley replaces matter with God as the cause and orderer of sensory experience. My imagined apple depends on my will. The apple I see on the table does not. Its steadiness, public availability, and lawlike order point to a mind greater than mine.

Key Ideas With Examples

• Immaterialism: the denial of material substance. Berkeley is not denying chairs and stones. He is denying that a chair is a hidden material support underneath all its perceived qualities. The chair is the ordered set of ideas we can see, touch, and use.
• Idea: anything immediately perceived, such as a color, sound, taste, pressure, pain, or visual shape. When you see a red apple, the red color and round visible shape are ideas in Berkeley's sense.
• Spirit or mind: an active perceiver. Ideas are passive; they just appear. Minds perceive, compare, remember, imagine, and will. Berkeley thinks human minds and God are spirits.
• Material substance: the supposed mind-independent stuff that supports qualities. Berkeley asks what this adds. If you remove every perceived quality from a cherry, such as redness, sweetness, roundness, firmness, and smell, there is nothing left that can be clearly described.
• Perceptual relativity: the same thing can appear differently to different perceivers or under different conditions. Lukewarm water feels warm to a cold hand and cool to a hot hand. Berkeley uses cases like this to argue that sensible qualities are tied to perception.
• Primary and secondary qualities: Locke and other early modern philosophers often treated size, shape, motion, and solidity as primary qualities in bodies themselves, while color, taste, and smell were secondary qualities produced in us. Berkeley argues that primary qualities also vary with perception, so they cannot rescue material substance.
• Common sense: ordinary trust in the world of houses, mountains, food, and other people. Berkeley thinks his view protects common sense because it keeps the objects we actually experience instead of moving reality behind experience into an unknowable realm.
• Skepticism: doubt about whether we know the world. Berkeley says materialism invites skepticism because it says the real object is something beyond all perception, while all we ever meet are ideas.
• God: the infinite mind that makes sensory experience regular and shared. If I leave a book in a room, Berkeley can say it continues to exist because it remains within God's perception and within the stable order God makes available to finite minds.

Why It Matters

Three Dialogues matters because it makes a radical view sound like a defense of ordinary experience. Berkeley does not say the world is fake. He says philosophers invented a needless layer called matter and then worried that we could never know it.

The book is also a major moment in Empiricism. Berkeley accepts the empiricist demand that knowledge answer to experience. Then he uses that demand against matter itself. If matter is never perceived, and if it explains nothing about what we perceive, why believe in it?

The dialogue form matters too. The earlier Treatise Concerning Principles of Human Knowledge made the same case more directly. Three Dialogues stages the objections through Hylas, so readers can watch the materialist position lose ground step by step.

Proponents, Critics, and Opponents

George Berkeley is the defender of the view. Philonous presents Berkeley's side: ordinary objects are real, but their reality is mind-dependent.

John Locke is an important background opponent. Berkeley accepts Locke's focus on ideas and experience, but rejects Locke's material substratum and the split between primary and secondary qualities.

David Hume inherits a world shaped by Berkeley's arguments. Berkeley's attack on matter helps push empiricism toward deeper questions about causation, selfhood, and what experience can justify.

Critics often say Berkeley confuses the act of thinking about something with the thing thought about. For example, I must think in order to imagine an unobserved tree, but it does not follow that I am imagining a tree that is being observed. Others object that God is doing too much work in the system: Berkeley removes material substance, then uses divine perception and divine causation to secure the stable world.

Still, the book remains powerful because it asks a sharp question: if matter is defined as something no one can perceive, why treat it as more real than the world we actually encounter?

Related Pages

• George Berkeley
• Treatise Concerning Principles of Human Knowledge
• Empiricism
• John Locke
• David Hume
• Skepticism