Philosophy seems to consist of two parts, Logic and Metaphysics. I exclude Ethics, for two reasons. In the first place, as the science of the end and aim of life, [ethics] seems to be exclusively psychical, and therefore to be confined to a special department of experience, while philosophy studies experience in its universal characteristics. In the second place, in seeking to define the proper aim of life, ethics seems to me to rank with the arts, or rather with the theories of the arts, which of all theoretical sciences I regard as the most concrete, while what I mean by philosophy is the most abstract of all the real sciences.