Three Dialogues between Hylas and Philonous

For George Berkeley, who speaks through the character of Philonous in the text, perception is existence. Berkeley’s motto, esse est percipi (to be is to be perceived) speaks directly to this argument. The argument is grounded in empiricism—a philosophical tradition holding that all we can know of the world is that which can be attained through direct experience. In the preface, Berkeley lays the groundwork for his argument, beginning by addressing the opposing view. He says, “Upon the common principles of philosophers, we are not assured of the existence of things from their being perceived. And we are taught to distinguish their real nature from that which falls under our senses. Hence arise scepticism and paradoxes” (3). Berkeley suggests in these remarks that rationalism, which enlists the use of reason and logic to gain knowledge of the world, creates skepticism. Continuing to diagnose the confusions that arise from rationalism, he adds sarcastically, “It is not enough, that we see and feel, that we taste and smell a thing. Its true nature, its absolute external entity, is still concealed. For, though it be the fiction of our own brain, we have made it inaccessible to all our faculties. Sense is fallacious, reason defective” (3). For Berkeley, the world that we directly experience through our senses is all that truly exists. He says to Hylas in Dialogue 1, “The idea or thing which you immediately perceive, neither sense nor reason informs you that it actually exists without the mind” (36). This is not necessarily a denial that matter exists, just a statement that in order for it to exist, it must be perceived. Knowledge of what actually exists can only be verified through direct observation. This is an empirical position.

In the text, Hylas struggles to fully comprehend Philonous’s argument for immaterialism, primarily because he insists that matter must exist in the world; it must have some form of absolute existence outside perception. He posits a series of arguments in favor of this view, including reference to the substratum, or a kind of indiscernible underlying substance in matter. He also argues that because matter takes up space (what he calls “extension,” one of the supposed “primary qualities” of matter), it must exist outside perception. Because he holds to the position that matter must exist independently from perception, he slides dramatically into skepticism. This is, in Berkeley’s view, the most significant problem with materialism.

At the opening of Dialogue 3, Hylas says, “Truly my opinion is, that all our opinions are alike vain and uncertain. What we approve to-day, we condemn tomorrow” (61). This descent into skepticism was set in motion toward the close of Dialogue 2 when he says, “The reality of things cannot be maintained without supposing the existence of matter” (58). Hylas makes the mistake of presuming that if Philonous’s account is correct, matter does not exist at all. Reality, therefore, is an illusion.

This is not what Philonous proposes, however. Philonous first expresses empathy for the crisis Hylas faces, saying, “[Y]ou are obliged to pull down your own hypothesis of material substance, and positively to deny the real existence of any part of the universe. And so you are plunged into the deepest and most deplorable scepticism that ever man was” (63). He then corrects his friend’s faulty assumptions, noting that even though reality exists only in the mind, it does not follow that reality is an illusion. For Berkeley, existence is no less; he argues that whatever sensible objects we see can only exist because we perceive them. This is not the equivalent of a full denial that sensible objects exist at all.