The Anthropocene is widely understood to mean the current "period of Earth's history during which humans have a decisive influence on the state, dynamics and future" of this planet. For several years, scientists in the Working Group on the 'Anthropocene' (AWG) have worked (and voted!) on defining the beginning of the Anthropocene in geochemical terms. The mid-20th century provides an obvious geochemical 'timestamp': fallout from nuclear weapons detonations. Which other chemicals and timestamps are being considered for marking the Anthropocene's start? How is 'define-by-committee' even working out for geological epochs? This talk boils the scientific background of the Anthropocene debate down for non-stratigraphers.