“The complete use of pure reason brings us finally from physical to metaphysical knowledge. But the concepts of metaphysical knowledge do not in themselves fully satisfy the demand of our integral being. They are indeed entirely satisfactory to the pure reason itself, because they are the very stuff of its own existence. But our nature sees things through two eyes always, for it views them doubly as idea and as fact and therefore every concept is incomplete for us and to a part of our nature almost unreal until it becomes an experience.”