The six headings under which the disciplines of philosophy are commonly classified are: metaphysics, which deals with such abstract subjects as cosmology, theology, and the nature of being; logic, which deals with the laws governing rational thinking, or, as it has been called, "the doctrine of fallacies"; ethics, which is the science of morality, individual responsibility, and character -- concerned chiefly with an effort to determine the nature of good; psychology, which is devoted to investigation and classification of those forms of phenomena referable to a mental origin; epistemology, which is the science concerned primarily with the nature of knowledge itself and the question of whether it may exist in an absolute form; and aesthetics, which is the science of the nature of and the reactions awakened by the beautiful, the harmonious, the elegant, and the noble.