Lester R. Brown, a prominent environmentalist and founder of the Worldwatch Institute and Earth Policy Institute, describes sustainable living in the twenty-first century as "shifting to a renewable energy-based, reuse/recycle economy with a diversified transport system."[6] Derrick Jensen ("the poet-philosopher of the ecological movement"), a celebrated American author, radical environmentalist and prominent critic of mainstream environmentalism argues that "industrial civilization is not and can never be sustainable". From this statement, the natural conclusion is that sustainable living is at odds with industrialization. Thus, practitioners of the philosophy potentially face the challenge of living in an industrial society and adapting alternative norms, technologies, or practices.