This chapter covers a response to the discourse of limits which stresses the unlimited capacity of ingenious humans to overcome ecological limits, especially when they are organized in capitalist markets. For Prometheans, long term trends show environmental improvement and declining resource scarcity, such that economic growth can therefore go on forever. This Promethean discourse has often been advanced by market economists, and has often been highly influential in government, especially in the United States. More recently a Promethean environmentalism looks forward to a ‘good Anthropocene’ in which government too plays a role in bringing natural systems under benign human control, so that technologies such as geoengineering can be used effectively against problems such as climate change. In the background of Promethean argument is an older cornucopian discourse that stresses natural abundance of resources and the capacity of ecosystems to absorb pollutants. Ecologists and Earth systems scientists are not convinced and remain critical of Promethean discourse.