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Nature is man's inorganic body -- that is to say, nature insofar as it is not the human body. Man lives from nature -- i.e., nature is his body -- and he must maintain a continuing dialogue with it is he is not to die. To say that man's physical and mental life is linked to nature simply means that nature is linked to itself, for man is a part of nature.

Karl Marx, Friedrich Engels, Philip Gasper (2005). “The Communist Manifesto: A Road Map to History's Most Important Political Document”, p.151, Haymarket Books
Nature is man's inorganic body -- that is to say, nature insofar as it is not the human body. Man lives from nature -- i.e., nature is his body -- and he must maintain a continuing dialogue with it is he is not to die.