Defining 'life'

Carol E. Cleland, Christopher F. Chyba

Research output: Contribution to journalReview article

178 Scopus citations


There is no broadly accepted definition of 'life.' Suggested definitions face problems, often in the form of robust counter-examples. Here we use insights from philosophical investigations into language to argue that defining 'life' currently poses a dilemma analogous to that faced by those hoping to define 'water' before the existence of molecular theory. In the absence of an analogous theory of the nature of living systems, interminable controversy over the definition of life is inescapable.

Original languageEnglish (US)
Pages (from-to)387-393
Number of pages7
JournalOrigins of life and evolution of the biosphere
Issue number4
StatePublished - Aug 1 2002
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Space and Planetary Science


  • Astrobiology
  • Definition of life
  • Europa
  • Natural kinds
  • Viking

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