Since the 19th century, social criticisms link the state of nature to the situation of man and humanity in general. Such criticisms first appears in Alexander von Humboldt, whose work forms the basis both for evolutionary theory and for the new science of ecology, based on a holistic scientific worldview, which is now considered less "scientific", since it connected both objective data and subjective experience. This phenomenon is expanding in the 20th century, when awareness of the multi-dimensional ecological crisis arises. Under such circumstances, radical groups portray the relationship between humans and nature and the ecological and social crisis as evidence of the need to "return" to nature as a source of truth and well being. Fascinating figures in the history of radical ecology include Rousseau, Henry David Threw, Emerson, John Muir, Deep Ecology, earth first !, Deep Green Resistance, and more. The course discused the main ideas of radical ecology and the revolutionary potential of these ideas, including their implementation on social criticism that goes against the most dominant institutions in our culture: science, government, medicine, and modern lifestyle, especially consumerism.