Three Dialogues Between Hylas and Philonous

Overview

About a hundred pages, published in 1713, George Berkeley’s second major statement of the philosophical position now generally called subjective idealism or immaterialism, restating, in the form of a dramatized conversation, the argument he had already made four years earlier in his more technical and, in his own judgment, insufficiently understood treatise, A Treatise Concerning the Principles of Human Knowledge. Berkeley was in his late twenties, already an Anglican clergyman and soon to become a bishop, and he wrote the Dialogues explicitly to reach a wider audience than the earlier treatise had, choosing the more accessible, conversational form partly in direct response to how badly the Principles had been received, frequently dismissed by contemporaries as either obviously false or simply unintelligible.

The conversation takes place over three successive mornings between Hylas, whose name derives from the Greek word for matter and who begins the dialogue as a confident defender of the ordinary, common-sense view that matter exists as a real, mind-independent substance, and Philonous, whose name means lover of mind and who serves throughout as Berkeley’s own spokesman, arguing for the position that nothing exists except minds, spirits, and the ideas those minds perceive. By the dialogue’s end Hylas has been led, through a sustained sequence of questions he finds himself unable to answer satisfactorily, to abandon his initial position entirely and adopt, in substance if not always by name, Philonous’s own immaterialism.

What happens

First Dialogue: the assault on matter through the sensible qualities. Hylas opens confidently defending the existence of matter as an independently existing substance, and skepticism, in his initial framing, as the position that denies the reliability of the senses, a position he assumes Philonous, as an immaterialist, must hold, while he himself, as a materialist, defends common sense.

Philonous inverts this expectation immediately, arguing that it is actually the materialist who is committed to a deep skepticism, since materialism posits a substance behind our ideas that can never itself be perceived or verified, while his own view stays entirely within what is actually perceived. He then leads Hylas through a systematic examination of sensible qualities, beginning with heat and cold, arguing that since the same water can feel warm to one hand and cold to another simultaneously, heat and cold cannot be qualities existing in the water itself, independent of any perceiver, but must exist only as ideas in the perceiving mind. Hylas, after resisting, concedes this for the so-called secondary qualities generally, taste, smell, sound, color, retreating to the claim that the primary qualities, extension, figure, motion and solidity, are different, genuinely existing in matter itself independent of any perception.

Philonous does not let this retreat stand. He presses the same kind of argument against extension and figure, pointing out that the same object appears differently sized and shaped depending on the observer’s distance or the instrument used to view it, a mite’s leg looking vastly different to the naked eye than under a microscope, and against motion, which appears faster or slower depending on the observer’s own relative frame of reference, arguing that primary qualities fare no better under scrutiny than secondary ones and are equally mind-dependent. By the end of the first dialogue, Hylas has been forced to concede that every sensible quality he can actually specify exists only as perceived, leaving him nothing concrete left to attribute to matter itself beyond an unspecified, entirely unperceivable substratum supposedly supporting these qualities from behind.

Second Dialogue: the emptiness of material substance. Hylas attempts several further retreats, suggesting matter might be an unknown substratum supporting qualities without itself possessing any of them, or that matter might cause our ideas without resembling them. Philonous methodically dismantles each: an entirely unknown substratum, stripped of every specifiable quality, is, he argues, no longer a meaningful concept at all but merely an empty word, since to say something exists while denying it has any of the properties by which existence could ever be recognized or specified is to say nothing intelligible about it whatsoever.

Third Dialogue: Philonous claims common sense for himself, and argues for God. Having secured Hylas’s abandonment of matter, Philonous spends the final dialogue on the harder rhetorical task: convincing Hylas, and the reader, that immaterialism, far from being the paradoxical or skeptical position it initially appeared, is actually the view that best preserves ordinary common sense about the reality and stability of the physical world. Philonous insists he does not deny the existence of tables, mountains, or trees at all; he denies only the philosophers’ invented notion of an unperceivable material substance supposedly lying behind these ordinary things, a notion, he argues, that no ordinary person actually believes in or needs, and whose removal changes nothing about how we actually encounter and interact with the world.

The dialogue’s final and most consequential positive move addresses an obvious objection: if to be is to be perceived, esse est percipi, what happens to objects when no finite mind is perceiving them, does the room I just left cease to exist the moment I close the door? Philonous’s answer invokes God: the continued, orderly, reliable existence of things even when no human being is perceiving them is secured by their being perceived continuously by an infinite mind, God, whose perpetual perception is what actually sustains the whole physical world’s real, ongoing existence, independent of any particular finite perceiver’s attention. This move lets Berkeley claim that his system, rather than undermining the reliability and independence of the physical world, actually provides a more secure foundation for it than materialism does, since it grounds the world’s continued existence directly in the mind of God rather than in an unverifiable material substance no one has ever actually perceived.

How to read it

Read the three dialogues in sequence and resist skipping ahead; the argument builds cumulatively, with the demolition of secondary and then primary qualities in the first dialogue setting up the collapse of material substance in the second, which in turn sets up Philonous’s positive case in the third that his own view, not Hylas’s original materialism, is the one that actually preserves common sense.

Work through the heat-and-cold and the relative-size arguments concretely, testing them against your own experience, since these specific examples are doing real argumentative work and are more persuasive worked through slowly than summarized.

Pay particular attention to the reversal Philonous stages in the third dialogue. It is easy to read the first two dialogues as pure demolition and miss that Berkeley’s larger strategic aim is not merely negative, dismantling belief in matter, but positive, establishing that his own immaterialism is the philosophically safer and more genuinely common-sense position, better able to resist skepticism than the materialism it replaces.

Notice how much weight the argument places on God at the very end. The invocation of an infinite perceiving mind to explain the continuity of unperceived objects is not an incidental theological flourish but a load-bearing part of the system, and Berkeley’s own vocation as a future bishop is directly relevant to understanding why this move mattered as much to him as the earlier epistemological arguments.

Read Locke’s Essay Concerning Human Understanding, at least its chapters on primary and secondary qualities, before or alongside this dialogue, since Berkeley is arguing directly against the version of the primary-secondary quality distinction Locke had made standard, and seeing what Locke actually claimed sharpens exactly what Berkeley thinks he has refuted.

Read Hume’s Treatise of Human Nature afterward to see the next step in this empiricist sequence: Hume accepts much of Berkeley’s argument against material substance but extends the same skeptical method to the self and to causation, arriving at conclusions considerably more unsettling than Berkeley’s own comfortably theological resolution.

Questions it raises

• Does Philonous’s argument against primary qualities, from their apparent relativity to observer and instrument, actually succeed as well as his argument against secondary qualities, or does it trade on a different and weaker kind of relativity?
• Is an unperceivable material substratum genuinely an empty, meaningless concept, as Philonous insists, or does Hylas give up this position too easily under pressure?
• Does grounding the continued existence of unperceived objects in God’s perpetual perception actually solve the problem it addresses, or does it merely relocate the mystery of unperceived existence onto an equally unverifiable claim about divine perception?
• Is Berkeley right that his own immaterialism preserves common sense better than materialism does, or does most people’s ordinary, unreflective sense of the world actually assume something closer to Hylas’s original position?
• If nothing exists except minds and the ideas minds perceive, what is actually doing the work of explaining why our perceptions are orderly, predictable and shared among different perceivers, rather than chaotic or private to each mind?
• How persuasive is the dialogue form itself as a vehicle for philosophical argument? Does staging the case as a conversation between a confident naive believer and a relentless questioner make the argument more convincing, or does it merely make Hylas’s concessions feel inevitable by design?