From Ayn Rand's Objectivist Ethics ... "Ethics is not a mystic fantasy -- nor a social convention -- nor a dispensible, subjective luxury, to be switched or discarded in any emergency. Ethics is an objective, metaphysical necessity of man'a survival -- not by the grace of the supernatural, nor of your neighbors nor of your whims, but by the grace of reality and the nature of life."
In other words, man has a spiritual nature in a real world universe where Man's creator (whatever) seems to have expected men to survive by using their real world minds.