Phenomenalism is a philosophical theory that suggests objects only exist as sensory experiences. According to this view, we can only know things through our perceptions, and if something is not being observed, it does not exist in any meaningful way. This idea challenges the notion of an objective reality independent of our experiences. The theory is often associated with the work of philosophers like George Berkeley, who argued that physical objects are collections of sensory experiences. In this framework, the existence of an object is contingent upon it being perceived, leading to the conclusion that reality is fundamentally tied to human perception.