The Great Soviet Encyclopedia (3rd Edition, 1970-1979) defines ' death' as: The cessation of the vital functions of an organism and the ensuing end of its life as an individual. Death is accompanied by the decomposition of proteins and other biopolymers, which are the principal material substrate of life. Modern views of dialectic materialism on the subject of death are based on the following idea expressed by F. Engels: "One can no longer consider scientific a physiology that does not regard death as an essential aspect of life ... or realize that the negation of life is an essential component of life: life must always be viewed in relation to its inevitable and immanent property—death."