Three Dialogues between Hylas and Philonous

Hylas meets Philonous the next morning, and the conversation picks up where the two left off. Hylas mentions that he has been dwelling on the previous day’s conversation and wrestling with many of the concepts Philonous raised. Hylas thinks he has discovered a possible way of refuting Philonous and discusses what the science of the day understood about the brain and the rest of the central nervous system—that the brain is the source of sensations caused by external objects. Philonous disputes Hylas’s apparently scientific analysis. Philonous argues that the brain conceives of itself as a brain. Since it cannot be directly experienced through the senses, the brain is an idea like any other idea. After Philonous pushes back against Hylas, the latter is now at a complete loss for further rebuttal. Hylas concedes that Philonous has proven him a skeptic; however, he also insists that Philonous is likewise a skeptic. Philonous again insists that he is not a skeptic. He repeats his claim that objects only exist inside the mind that perceives them, yet they do exist. The materialist contention that objects exist outside the mind, in Philonous’s view, is actually a denial that they exist at all.

Philonous pivots to a more robust explanation of idealism, specifically that since humans are not in full command of our immediate sensory experiences, there must be a source for these. Because sensory experience happens involuntarily, Philonous argues that it must be the result of some higher order of being, namely God. He says, “As sure therefore as the sensible world really exists, so sure is there an infinite omnipresent spirit who contains and supports it” (46-47). Philonous argues that one’s sensory experiences are ideas in the mind of God. He contends that this is not a description of a passive God found in the things of the material world—the view he accuses Hylas and other materialists of taking. Hylas asks Philonous, “[A]re not you too of opinion that we see all things in God?” (49). Here, Philonous distinguishes his view from a prevailing sentiment of the time. After a lengthy explanation of how his view differs, Philonous sums it up by stating, “[T]here is a mind which affects me every moment with all the sensible impressions I perceive” (50). This, he points out, is not the same as seeing God in all things.

Hylas does not fully concede this point, instead stating that even if Philonous’s view of God is accepted, there may yet be cause to believe in a “third nature” in addition to those of spirits and ideas.

Philonous again returns to his main argument that nothing exists outside of the mind that perceives it. He asks Hylas to defend his belief in matter again. Hylas contends that he cannot ascertain any cause for his ideas other than matter and must therefore conclude that matter is the source of ideas. Philonous turns to semantics, re-establishing the common definition of matter before posing to Hylas the same question regarding the existence of matter: Can it exist without a mind that perceives it? Hylas does not dispute the argument that God is the source of all things, ideas included, but “that subordinate to the supreme agent there is a cause of a limited and inferior nature, which concurs in the production of our ideas” (51). Philonous turns the conversation to primary properties once again, this time centering on motion. Philonous argues that motion must be perceived in order to exist. Hylas finally concludes that matter is the instrument subordinate to God “in the production of our ideas” (52). After Philonous pokes holes in this assertion, Hylas becomes agitated and accuses Philonous of teasing him for his position.

Philonous argues that because we perceive things involuntarily, volition is not an immediate cause of perception. He suggests that the reason we have immediate perceptions is because God is the instrument that makes it happen. Hylas concedes that matter is not the instrument that causes ideas (as he previously claimed) before moving on to assert that matter is an occasion that Hylas defines as “an inactive unthinking being, at the presence whereof God excites ideas in our minds” (54). Hylas also acknowledges when pressed that he cannot define what he means when he says, “inactive unthinking being” (54). Hylas continues, stating that because there is a consistency to the occasions of matter, this should prove that it exists outside the mind. Philonous dismantles this position by pointing out that an omniscient, rational God would create this patterned consistency. He also contends that Hylas is using reason to postulate these positions, proving once again, at least by his evaluation, that matter cannot be empirically proven to exist. Any claim that matter does exist must rely on inference rather than on immediate perception.

Philonous offers a brief summation of the argument to this point, once again forcing Hylas to define what he thinks matter really is. Hylas now claims that matter consists of something unknown—a definition Philonous rejects as pure abstraction. When he asks Hylas where this “something unknown” exists, Hylas recognizes the trap (“something unknown” can exist only in the mind) and refuses to answer.

The two continue to argue about the existence of matter. Hylas finally states that because Philonous cannot prove that the existence of matter is impossible, holding to the fact of its existence in the manner Hylas is doing is an acceptable position. Philonous vehemently disputes this until finally Hylas states, “I acknowledge you have proved that matter is impossible; nor do I see what more can be said in defense of it. But at the same time that I give up this, I suspect all my other notions” (60). While conceding a large measure to Philonous, he has yet to give up the position that matter does indeed exist, and he requests one more conversation to take place the following day.