ABSTRACT

The question ‘what is life?’ is foundational to biology and especially important to astrobiologists, who may one day encounter utterly alien life, and scientists trying to understand the transition from a nonliving chemical reaction system to a primitive living thing. The most popular approach to answering this question is to provide a “definition” of life. In the first part of this talk, I explain why traditional and non-traditional approaches to defining life are mistaken. A scientifically compelling understanding of the nature of life presupposes an empirically adequate scientific theory of life, as opposed to definition of life. Scientific theories cannot be encapsulated by definitions nor can definitions of the natural kinds that they subsume be inferred from them. In the second part of this talk, I sketch a strategy for searching for alien forms of life without the guidance of a definition or universal theory of life. I close with an application to NASA’s fledgling search for extraterrestrial life.

About the Speaker:

Carol E. Cleland is Professor of Philosophy at the University of Colorado (Boulder). She received her B.A. in mathematics from the University of California (Santa Barbara) and her Ph.D. in philosophy from Brown University. Her current research interests are in the areas of scientific methodology, historical science, biology (especially microbiology, origins of life, the nature of life, and astrobiology), and the theory of computation. Cleland’s published work has appeared in major science journals (Current Organic Chemistry, Origins of Life and Evolution of the Biosphere, Geology, Astrobiology, International Journal of Astrobiology, and Theoretical Computer Science) as well as in leading philosophy journals (Philosophy of Science, British Journal of Philosophy of Science, Synthese, and Biology and Philosophy). She co-edited with Mark Bedau an anthology, The Nature of Life: Classical and Contemporary Perspectives from Philosophy and Science, and is currently finishing a single authored book (The Quest for a Universal Theory of Life; Searching for life as we don’t know it), which is under contract with Cambridge University Press.