From the greek eidos, meaning a visible image, form or shape; typically, the term suggests a mental conception, image or notion. In platonic philosophy, it designates an immaterial, universal, and eternal pattern or type of any class of thing, of which objects of sense are imperfect copies. This philosophical stance more generally falls under the term idealism, i.e. That the objects of our external perception are in reality immaterial ideas. Such ideas might be mental constructs particular to human being, as immanuel kant argued; alternatively, reality as a whole might be ideal in the sense of its being an fundamentally an object of conscious in itself, as georg wilhelm friedrich hegel maintained.