In Extraenvironmentalist #31 we speak with Dr. Joseph Tainter about collapse, complexity and energy. Dr. Tainter recently co-authored Drilling Down which explains why the BP Gulf Oil spill occurred in terms of the complexity that supports our society. We discuss concepts of complexity, energy and a meaningful definition of sustainability. In our conversation, Dr. Tainter covers the dynamics of the Roman Empire as it moved further down the road of collapse; debasing its currency and unraveling due the expenses of foreign wars. Seth and I ask if energy alternatives exist that can support civilization, such as from using solar photovoltaics or wind power. If they can’t, are we trapped in a complexity spiral with no way out?