One who denies the existence of spiritual substances or agents, and maintains that spiritual phenomena, so called, are the result of some peculiar organization of matter. A believer in philosophical materialism.
a non-dualist, a monist, and if some day he comes to know that there is no matter, that only spirit is, only consciousness is, then he will have no difficulty in being transformed
a person who believes that the world is external to them, existed before them, and that their ideas can become forces in recreating and changing the world