In popular culture, an idealist is generally defined as “a person who sees the world as it could be rather than as it currently exists.” An idealist is full of hope, even to the point of impracticality; Don Quixote was an idealist. However, that definition has little to do with idealism as a philosophy. Idealism, for the purpose of this article, is the belief that reality is fundamentally a mental concept. In this worldview, everything knowable is composed of the mind or spirit and reality is defined by one’s self-consciousness. Various philosophers have taught idealism throughout history, including Plato.