Existentialism (/??z??st?n??l?z?m/) is a term applied to the work of certain late-19th- and 20th-century European philosophers who, despite profound doctrinal differences, shared the belief that philosophical thinking begins with the human subject--not merely the thinking subject, but the acting, feeling, living human individual. While the predominant value of existentialist thought is commonly acknowledged to be freedom, its primary virtue is authenticity.