Metaphors can be used to help people to know new things and understand new concepts. By changing the way people perceive things, they can also provide guidance for future action. They are, therefore, sometimes used as means to popularize new knowledge or concepts in science education. In At War with the Planet
, the first chapter of Making Peace with the Planet, biologist Barry Commoner uses the metaphor "environmental crisis as war" and its extensions to raise the public awareness of the environmental crisis, its gravity and the underlying causes. By examining dialectically the interplay between technology and the environment, Commoner reveals the intersubjectivity between man and nature and his view of ecological holism. The use of war as a metaphor for environmental crisis and its extensions by later environmentalists further proves the attraction and expressiveness of such metaphors and confirms the important role metaphors can play in popularizing new knowledge or concepts in science.