Berkeley's A Treatise Concerning the Principles of Human Knowledge

Berkeley's *A Treatise Concerning the Principles of Human Knowledge* argues that everything we perceive—objects, colors, sounds—exists only as ideas in our minds. He challenges the notion that material objects exist independently outside of perception, suggesting instead that their existence depends on being perceived. For Berkeley, being is essentially "perceived," and what we call physical objects are collections of ideas perceived by minds, including God's. This view emphasizes the active role of perception in creating reality, asserting that our knowledge is based on perception rather than on an independent material substance.