At the core of the Perennial Philosophy we find four fundamental doctrines. First: the phenomenal world of matter and of individualized consciousness - the world of things and animals and men and even gods - is the manifestation of a Divine Ground within which all partial realities have their being, and apart from which they would be non-existent. Second: human beings are capable not merely of knowing about the Divine Ground by inference; they can also realize its existence by a direct intuition, superior to discursive reasoning. This immediate knowledge unites the knower with that which is known. Third: man possesses a double nature, a phenomenal ego and an eternal Self, which is the inner man, the spirit, the spark of divinity within the soul. It is possible for a man, if he so desires, to identify himself with the spirit and therefore with the Divine Ground, which is of the same or like nature with the spirit. Fourth: man's life on earth has only one end and purpose: to identify himself with his eternal Self and so to come to unitive knowledge of the Divine Ground.