Summary

Philonous and Hylas meet again, and Philonous is surprised to find that Hylas has succumbed into a deep skepticism about all of his knowledge. He claims that he now knows the deep: that all we know is nothing, since what we perceive are only appearances and not how things really are. Philonous expresses his wonder that Hylas can doubt the very things he sees with his own eyes. In Philonous’s view, what exists is exactly what he sees and feels. Existence, for him, is simply perception. There is still an external reality, but it is made of ideas and exists only in the mind of God.

Hylas now tries to turn Philonous’ techniques on Philonous himself, to reduce him to skepticism too. Just like no idea can represent matter, so Hylas argues that no idea can represent God, since...