The navel, umbilicus, omphalodium, or belly button is the round cicatrix (scar tissue) protuberance located on the abdomen where the umbilical cord was originally attached. Since the dawn of time, the navel has been the focus of a reflective form of philosophical contemplation known as omphalopsychism. This might be because the navel literally represents the location of birth, or perhaps because it is where the eye lazily falls when one is reclining naked. A number of omphalopsychite groups have existed through history--perhaps the most famous of which were the Hesychasts, a sect of quietists who (from c.1050 CE) practiced gazing at the navel to induce a hypnotic reverie. The Hesychasts believed that through a rigorous regime of asceticism, devotion, and deep contemplation of the body, a mystic light--no less than the uncreated divine light of God--could be seen. The question of whether Adam and Eve had navels (given that they were created by God) is one that has vexed theologians for some times. Incidentally, a number of artists, not least Albrecht Dürer and William Blake, have chosen to depict Adam and Eve with omphalodia.
Claude Debussy (1862-1918)