Philonous’s name is derived from the Greek term for “love of mind.” Philonous is effectively the voice of George Berkeley himself. As a figure in the text, Philonous’s primary purpose is to advance Berkeley’s immaterialist argument. At times, Philonous’s tone becomes adamant, and he sometimes expresses agitation at Hylas’s refusal to concede the points Philonous makes. At other times, Philonous borders on mockery of his friend, even to the point where Hylas notices and accuses Philonous of “teasing” him.

For the first two dialogues, Philonous lays the foundation of his argument that matter does not exist outside the mind. As the third dialogue begins, Hylas is much more on the offensive and has come prepared with questions meant to poke holes in Philonous’s system. In this manner, Berkeley anticipates possible objections to his argument, with the opposition represented by Hylas and his rebuttals expressed through the voice of Philonous.

Philonous, like Hylas, is a devout man, a believer in the Christian God and scriptures. However, his understanding of God is much different from Hylas’s or from that of most Christians. Instead of seeing God in all things, Philonous believes that we see God’s ideas.