Philosophy is considered a branch of the language arts and involves the study of the truths or principles underlying all knowledge. Philosophical study involves a continuous attempt to analyze, interpret, and logically explain what humans believe, value, and do. While occupations are generally only indirectly linked to the study of philosophy, a number of other disciplines, avocations and leisure time activities offer additional attractions for the interested student. Among the major sub-branches are metaphysics, logic and axiology.