A Treatise Concerning the Principles of Human Knowledge, Part 1 (Commonly called "Treatise" when referring to Berkeley's works) is a 1710 work by the Irish Empiricist philosopher George Berkeley. It largely seeks to refute the claims made by his contemporary John Locke about the nature of human perception. Both Locke and Berkeley agreed that there was an outside world, and it was this world which caused the ideas one has within one's mind. Berkeley sought to prove that the outside world was also composed solely of ideas, suggesting that "Ideas can only resemble Ideas". This world was given logic and regularity by some other force, which Berkeley concluded was God. Part 2 of the Treatise was never written.