"Three Dialogues Between Hylas and Philonous in Opposition to Sceptics and Atheists" by George Berkeley is a philosophical work written in 1713. Through a dialogue between two characters, Berkeley challenges the existence of material substance itself. Philonous, representing Berkeley's views, systematically argues that what we call matter is merely a collection of perceptions dependent on the mind. He dismantles his opponent Hylas's belief in material objects by showing that all sensible qualities—color, sound, shape—exist only through perception. The work presents Berkeley's radical idealism: reality consists of ideas, not material forms. (This is an automatically generated summary.)