Marcus Aurelius is the most intolerable of human types. He is an unselfish egoist. An unselfish egoist is a man who has pride without the excuse of passion. Of all conceivable forms of enlightenment the worst is what these people call the Inner Light. Of all horrible religions the most horrible is the worship of the god within. Any one who knows any body knows how it would work; any one who knows any one from the Higher Thought Centre knows how it does work. That Jones shall worship the god within him turns out ultimately to mean that Jones shall worship Jones. Let Jones worship the sun or moon, anything rather than the Inner Light; let Jones worship cats or crocodiles, if he can find any in his street, but not the god within.
G.K. Chesterton, Orthodoxy.