Origins of life and evolution of the biosphere

, Volume 32, Issue 4, pp 387–393 | Cite as

Defining ‘Life’

  • Carol E. Cleland
  • Christopher F. Chyba


There is no broadly accepted definition of ‘life.’ Suggested definitions face problems, often in theform of robust counter-examples. Here we use insights fromphilosophical investigations into language to argue thatdefining `life' currently poses a dilemma analogous to thatfaced by those hoping to define `water' before the existenceof molecular theory. In the absence of an analogous theoryof the nature of living systems, interminable controversyover the definition of life is inescapable.

definition of life astrobiology Viking Europa natural kinds 


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Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • Carol E. Cleland
    • 1
  • Christopher F. Chyba
    • 2
    • 3
  1. 1.Department of Philosophy and the Center for AstrobiologyUniversity of ColoradoBoulderUSA
  2. 2.Center for the Study of Life in the UniverseSETI InstituteMountain View
  3. 3.Department of Geological and Environmental SciencesStanford UniversityStanfordUSA

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