Metaphysical Idealism is a philosophical theory that posits that reality is fundamentally mental or immaterial. According to this view, the material world is either dependent on or a manifestation of the mind. This means that what we perceive as physical objects and events are ultimately rooted in consciousness or ideas rather than existing independently. One of the key figures associated with metaphysical idealism is George Berkeley, who famously argued that "to be is to be perceived." This perspective challenges the notion of an objective reality existing outside of our perceptions, suggesting instead that the mind plays a crucial role in shaping our understanding of existence.