How did George Berkeley explain the nature of physical objects?

George Berkeley, a central figure in empiricism, argued that physical objects are not material substances existing independently of the mind. Instead, he proposed that objects such as tables and chairs are collections of sensible ideas—or sense-data—directly perceived by the mind.12

Berkeley’s philosophy is summarized by the doctrine esse est percipi, or "to be is to be perceived". He rejected the existence of matter as an underlying substance, arguing that because we only ever perceive ideas, it is contradictory to claim that objects exist "behind" or independent of those perceptions.12

Regarding objects not currently being perceived by humans, Berkeley maintained that they do not simply vanish. He argued that these objects continue to exist because they are perceived by the mind of God, whose constant perception sustains the physical world. By defining physical reality as a collection of ideas rather than material substance, Berkeley believed he was upholding a common-sense view of reality, asserting that qualities like density and permanence are simply additional ideas that constitute our experience of objects.21