In classical theism, God is characterized as the metaphysically ultimate being (the first, timeless, absolutely simple and sovereign being, who is devoid of any anthropomorphic qualities), in distinction to other conceptions such as theistic personalism, open theism, and process theism. Classical theists do not believe that God can be completely defined. They believe it would contradict the transcendent nature of God for mere humans to define him. Robert Barron explains by analogy that it seems impossible for a two-dimensional object to conceive of three-dimensional humans.