abstract:The Medea hypothesis is a term coined by paleontologist Peter WardPeter Ward (2009), The Medea Hypothesis: Is Life on Earth Ultimately Self-Destructive?, ISBN 0-691-13075-2 for the anti-Gaian hypothesis that multicellular life, understood as a superorganism, is suicidal; in this view microbial-triggered mass extinctions are attempts to return the Earth to the microbial dominated state it has been for most of its history.