To arrive at the understanding that the universe is non-material and is mental, is to be liberated from materialism. It produces a sensation like that felt by a prisoner who has spent half a lifetime cooped up in a dark and dingy fetid dungeon and who is suddenly liberated, set free, put out of doors in the bright sunshine and fresh clean air. For to be a materialist means to be one imprisoned in the false belief that the matter-world is the real world; to become spiritual is to perceive that all objects are mental ones; the revelation of the mental nature of the universe is so stupendous that it actually sets mind and feeling free from their materialistic prison and brings the whole inner being into the dazzling sunshine of truth, the fresh atmosphere of Reality. All those who believe in the materiality of the material world and not in its mental nature, are really materialists--even if they call themselves religious, Christians, spiritualists, occultists, or Anthroposophists. The only way to escape materialism is not to become a follower of any psychic cult or religious faith, but to enquire with the mind into the truth of matter and to be rewarded at length by the abiding perception of its mental Nature. All other methods are futile, or at best are but preparatory and preliminary steps.
-- Notebooks Category 21: Mentalism > Chapter 5 : The Key To the Spiritual World > # 96
-- Perspectives > Chapter 21: Mentalism > # 61
