Skip to main content Accessibility help

We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.

Close cookie message
×
Hostname: page-component-669899f699-chc8l Total loading time: 0 Render date: 2025-05-06T04:02:16.803Z Has data issue: false hasContentIssue false

26 - Does ‘life’ have a definition?

Published online by Cambridge University Press:  10 November 2010

Mark A. Bedau  and
Carol E. Cleland
By
Carol Cleland  and
Christopher Chyba
Mark A. Bedau
Affiliation:
Reed College, Oregon
Carol E. Cleland
Affiliation:
University of Colorado, Boulder
Get access

Summary

INTRODUCTION

The question “What is life?” is foundational to biology and especially important to astrobiologists who may one day encounter utterly alien life. But how should one approach this question? One widely adopted strategy among scientists is to try to define ‘life’. This chapter critically evaluates this strategy. Drawing from insights gained by philosophical investigations into the nature of logic and language, we argue that it is unlikely to succeed. We propose a different strategy, which may prove more fruitful in searches for extraterrestrial life.

We begin by reviewing the history of attempts to define ‘life’, and their utility in searches for extraterrestrial life. As will become apparent, these definitions typically face serious counterexamples, and may generate as many problems as they solve.

To explain why attempts to define ‘life’ are fraught with so many difficulties, we must first develop the necessary philosophical background. Therefore, on pp. 328–331 we discuss the general nature of definition and of so-called theoretical identity statements. Pages 332–334 then apply the material developed in these sections to the project of defining ‘life’. We argue that the idea that one can answer the question “What is life?” by defining ‘life’ is mistaken, resting upon confusions about the nature of definition and its capacity to answer fundamental questions about natural categories (Cleland & Chyba 2002).

To answer the question “What is life?” we require not a definition but a general theory of the nature of living systems.

Type
Chapter
Information
The Nature of Life
Classical and Contemporary Perspectives from Philosophy and Science
 , pp. 326 - 339
Publisher: Cambridge University Press
Print publication year: 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Book purchase

Temporarily unavailable

References

Adami, C. (1998). Introduction to artificial life. New York: Springer-Verlag.CrossRefGoogle Scholar
Aristotle, (1941). De anima, trans. Smith, J. A.. In McKeon, R. (Ed.), The basic works of Aristotle (pp. 535–606). New York: Random House.Google Scholar
Audi, R. (Ed.) (1995). The Cambridge dictionary of philosophy. Cambridge, UK: Cambridge University Press.
Bada, J. (2001). State-of-the-art instruments for detecting extraterrestrial life. Proceedings of the National Academy of Sciences, 98, 797–800.CrossRefGoogle ScholarPubMed
Banfield, J. F., Moreau, J. W, Chan, C. S., Welch, S. A., & Little, B. (2001). Mineralogical biosignatures and the search for life on Mars. Astrobiology, 1(4), 447–465.CrossRefGoogle ScholarPubMed
Bauer, M. (1968). Precious stones II. New York: Dover.Google Scholar
Bedau, M. (1996). The nature of life. In Boden, M. A. (Ed.), The philosophy of artificial life (pp. 332–357). Oxford: Oxford University Press.Google Scholar
Benner, S., Devine, K., Matveeva, L., & Powell, D. (2000). The missing molecules on Mars. Proceedings of the National Academy of Sciences, 97, 2425–2430.CrossRefGoogle ScholarPubMed
Biemann, K., Oro, J., Toulmin, P., et al. (1977). The search for organic substances and inorganic volatile compounds in the surface of Mars. The Journal of Geophysical Research, 82, 4641–4658.CrossRefGoogle Scholar
Chao, L. (2000). The meaning of life. Bioscience, 50, 245–250.CrossRefGoogle Scholar
Chyba, C. F. & McDonald, G. D. (1995). The origin of life in the solar system: Current issues. Annual Review of Earth and Planetary Sciences, 23, 215–249.CrossRefGoogle ScholarPubMed
Chyba, C. F. & Phillips, C. B. (2001). Possible ecosystems and the search for life on Europa. Proceedings of the National Academy of Sciences, 98, 801–804.CrossRefGoogle ScholarPubMed
Chyba, C. F. & Phillips, C B. (2002). Europa as an abode of life. Origins of Life and Evolution of the Biosphere, 32, 47–68.CrossRefGoogle ScholarPubMed
Cleland, C. E. (2001). Historical science, experimental science, and the scientific method. Geology, 29, 978–990.2.0.CO;2>CrossRefGoogle Scholar
Cleland, C. E. (2002). Methodological and epistemic differences between historical science and experimental science. Philosophy of Science, 69, 474–496.CrossRefGoogle Scholar
Cleland, C. E. & Chyba, C. F. (2002). Defining ‘life.’ Origins of Life and Evolution of the Biosphere, 32, 387–393.CrossRef
Conrad, P. G., & Nealson, K. H. (2001). A non-Earth-centric approach to life detection. Astrobiology, 1, 15–24.CrossRefGoogle Scholar
da Vinci, L. (1513). II codice arundel (no. 263, fol. 57r.). Quoted in Witcombe, C. (Ed.), Leonardo da Vinci and water (p. 734), trans. MacCurdy, E.. Available at http://witcombe.sbc.edu/water/artleonardo.html (accessed August, 2008).Google Scholar
Dawkins, R. (1983). Universal Darwinism. In Bendall, D. S. (Ed.), Evolution from molecules to men (pp. 403–425). Cambridge, UK: Cambridge University Press.Google Scholar
Dennett, D. (1995). Darwin's dangerous idea: Evolution and the meanings of life. New York: Simon & Schuster.Google Scholar
Dyson, F. (1985). Origins of life. Cambridge, UK: Cambridge University Press.Google Scholar
Feinberg, G. & Shapiro, R. (1980). Life beyond Earth: Intelligent Earthlings' guide to the universe. New York: William Morrow.Google Scholar
Fleischaker, G. R. (1990). Origins of life: An operational definition. Origins of Life and Evolution of the Biosphere, 20, 127–137.CrossRefGoogle Scholar
Gilbert, W. (1986). The RNA world. Nature, 319, 618.CrossRefGoogle Scholar
Glavin, D., Schubert, M., Botta, O., Kminek, G., & Bada, J. (2001). Detecting pyrolysis products from bacteria on Mars. Earth and Planetary Science Letters, 185, 1–5.CrossRefGoogle Scholar
Harold, F. M. (2001). Postscript to Schrödinger: So what is life?American Society for Microbiology News, 67, 611–616.Google Scholar
Joyce, G. F. (1994). Forward. In Deamer, D. and Fleischaker, G. (Eds.), Origins of life: The central concepts (pp. xi-xii). Boston: Jones & Bartlett.Google Scholar
Joyce, G. F. (1995). The RNA world: Life before DNA and protein. In Zuckerman, B. and Hart, M. (Eds.), Extraterrestrials: Where are they? II (pp. 139–151). Cambridge, UK: Cambridge University Press.CrossRefGoogle Scholar
Kamminga, H. (1988). Historical perspective: The problem of the origin of life in the context of developments in biology. Origins of Life and Evolution of the Biosphere, 18, 1–11.CrossRefGoogle ScholarPubMed
Kauffman, S. (2000). Investigations. Oxford: Oxford University Press.Google Scholar
Klein, H. P. (1978). The Viking biological experiments on Mars. Icarus, 34, 666–674.CrossRefGoogle Scholar
Klein, H. P. (1979). Simulation of the Viking biology experiments: An overview. Journal of Molecular Evolution, 14, 161–165.CrossRefGoogle ScholarPubMed
Klein, H. P. (1999). Did Viking discover life on Mars?Origins of Life and Evolution of the Biosphere, 29, 625–631.CrossRefGoogle ScholarPubMed
Koshland, D. E. (2002). The seven pillars of life. Science, 295, 2215–2216.CrossRefGoogle ScholarPubMed
Kuhn, T. S. (1962). The structure of scientific revolutions. Chicago: University of Chicago Press.Google Scholar
Lahav, N. (1999). Biogenesis: Theories of life's origins. New York: Oxford University Press.Google Scholar
Lange, M, (1996). Life, ‘artificial life,’ and scientific explanation. Philosophy of Science, 63, 225–244.CrossRefGoogle Scholar
Lavoisier, A. L. (1783). On the nature of water and on experiments which appear to prove that this substance is not strictly speaking an element but that it is susceptible of decomposition and recomposition, trans. Giunta, C.. Observations sur la Physique, 23, 452–455. Available at http://web.lemoyne.edu/faculty/giunta/laveau.html (accessed August, 2008).Google Scholar
Levin, G. V. & Levin, R. L. (1998). Liquid water and life on Mars. Proceedings of SPIE—The International Society for Optical Engineering, 3441, 30–41.Google Scholar
Levin, G. V. & Straat, P. A. (1979). Completion of the Viking labeled release experiment on Mars. Journal of Molecular Evolution, 14, 167–183.CrossRefGoogle ScholarPubMed
Lloyd, G. E. R. (1982). Early Greek science: Thales to Aristotle. London: Chatto & Windus.Google Scholar
Locke, J. (1689). An essay concerning human understanding. Oxford: Oxford University Press.Google Scholar
MacCurdy, E. (2003). The notebooks of Leonardo da Vinci, definitive edition in one volume. Old Saybrook, CT: Konecky & Konecky.Google Scholar
Matthews, G. B. (1977). Consciousness and life. Philosophy, 52, 13–26.CrossRefGoogle Scholar
Mayr, E. (1982). The growth of biological thought. Cambridge, MA: Belknap Press.Google Scholar
McKay, C. P. (1994). Origins of life. In Shirley, J. and Fairbridge, R. (Eds.), Van Nostrand Reinhold encyclopedia of planetary sciences and astrogeology (pp. 387–391). New York: Van Nostrand.Google Scholar
Monod, J. (1971). Chance and necessity: An essay on the natural philosophy of modern biology. London: Alfred A. Knopf.Google Scholar
Nagel, E. (1961). The structure of science: Problems in the logic of scientific explanation. New York: Harcourt, Brace & World.Google Scholar
Nealson, K. H., & Conrad, P. G. (1999). Life: Past, present and future. Philosophical Transactions of the Royal Society of London, 354, 1923–1939.CrossRefGoogle ScholarPubMed
New, M. & Pohorille, A. (2000). An inherited efficiencies model of non-genomic evolution. Simulation Practice and Theory, 8, 99–108.CrossRefGoogle Scholar
Pohorille, A. & New, M. (2000). Models of protocellular structures, functions, and evolution. In Palyi, G., Zucchi, C., and Caglioti, L. (Eds.), Frontiers of life (pp. 37–42). New York: Elsevier.Google Scholar
Putnam, H. (1973). Meaning and reference. Journal of Philosophy, 70, 699–711.CrossRefGoogle Scholar
Putnam, H. (1975). The meaning of meaning. In Putnam, H. (Ed.), Mind, language and reality: Philosophical papers, volume II (pp. 215–271). Cambridge, UK: Cambridge University Press.CrossRefGoogle Scholar
Rasmussen, S. (1992). Aspects of information, life, reality, and physics. Artificial Life, 2, 767–774.Google Scholar
Ray, T. S. (1992). An approach to the synthesis of life. Artificial Life, 2, 371–408.Google Scholar
Roberts, G. (1994). The mirror of alchemy: Alchemical ideas in images, manuscripts and books. Toronto: University of Toronto Press.Google Scholar
Rode, B. M. (1999). Peptides and the origin of life. Peptides, 20, 773–786.CrossRefGoogle ScholarPubMed
Rizzotti, M. (Ed.) (1996). Defining life. Padova: Padova University Press.
Sagan, C. (1970). Life. In Encyclopedia Britannica (15th ed.) (pp. 985–1002). Chicago: Encyclopedia Britannica, Inc.Google Scholar
Sagan, C. (1974). The origin of life in a cosmic context. Origins of Life and Evolution of the Biosphere, 5, 497–505.CrossRefGoogle Scholar
Schrödinger, E. (1945). What is life? The physical aspect of the living cell. Cambridge, UK: Cambridge University Press.Google Scholar
Schulze-Makuch, D., Guan, H., Irwin, L., & Vega, E. (2002). Redefining life: An ecological, thermodynamic, and bioinformatic approach. In Palyi, G., Zucchi, C., and Caglioti, L. (Eds.), Fundamentals of life (pp. 169–179). New York: Elsevier.Google Scholar
Schwartz, S. P. (1977). Introduction. In Schwartz, S. (Ed.), Naming, necessity, and natural kinds (pp. 13–41). Ithaca: Cornell University Press.Google Scholar
Shapiro, R. & Feinberg, G. (1995). Possible forms of life in environments very different from the Earth. In Zuckerman, B. and Hart, M. (Eds.), Extraterrestrials: Where are they? (pp. 165–172), Cambridge, UK: Cambridge University Press.CrossRefGoogle Scholar
Shelley, M. (1818). Frankenstein: Or the modern Prometheus. London: Lackington, Hughes, Harding, Mavor & Jones.Google Scholar
Shields, C. (1999). Order in multiplicity. Oxford: Oxford University Press.Google Scholar
Sober, E. (2003). Learning from functionalism—Prospects for strong artificial life. In Langton, C., Taylor, C, Farmer, J. D., and Rasmussen, S. (Eds.), Artificial life II (Santa Fe Institute studies in the sciences of complexity, proceedings vol. X) (pp. 749–765), Oxford; Boulder, CO: Westview.Google Scholar
Storrie-Lombardi, M, Hug, W., McDonald, G., Tsapin, A., & Nealson, K. (2001). Hollow cathode ion laser for deep ultraviolet Raman spectroscopy and fluorescence imaging. Review of Scientific Instruments, 72, 4452–4459.CrossRefGoogle Scholar
Sullivan, W. T. & Baross, J. A. (2007). Planets and Life. Cambridge: Cambridge University Press.CrossRefGoogle Scholar
Wittgenstein, L. (1953). Philosophical investigations, trans. Anscombe, G. E. M.. New York: Macmillan.Google Scholar

Save book to Kindle

To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×