How did Berkeley define existence?

Berkeley's definition of existence hinges on his philosophical stance known as idealism, which posits that reality is fundamentally tied to perception. He famously articulated the notion that "to be is to be perceived," meaning that something only exists if it can be perceived by a mind. This perspective challenges the materialistic view of existence, asserting that objects do not possess an independent existence outside of perception. For Berkeley, entities—whether they are physical objects or ideas—are only real when they are being experienced or observed by someone. This presents a radical view of reality, suggesting that perception is key to existence itself.