SETI Talks: Can we define life? Should we?

SETI Talks

Tags: SETI Talks, Astrobiology

Time: Wednesday, Aug 18, 2021 -

Location: Online

What is the difference between you and a rock? Are stars alive? Is a computer virus a living being? These may seem like easy questions, but scientists have struggled to formulate a universal definition of life, to draw the line between the living and the inanimate. Can life even be defined? Is such an endeavor even helpful?

We think we can intuitively recognize whether something is alive or not. But nature shows many examples that are difficult to categorize as life or non-life. The challenge may intensify as other worlds in our universe open up to exploration.
“It is commonly said,” the scientists Frances Westall and André Brack wrote in 2018, “that there are as many definitions of life as there are people trying to define it.”  Is it possible to find life beyond Earth if we disagree about what life represents?

We invited two scientists to join us for this month's SETI Talks to discuss this state of affairs. Haley Sapers, an astrobiologist at Caltech who studies living organisms we might find on Mars, and Carol Cleland, a professor of philosophy at the University of Colorado, Boulder, who wrote “The Quest for a Universal Theory of Life: Searching for life as we don’t know it.”
With Molly Bentley, executive producer and co-host of the Big Picture Science radio show, these two scientists will explore ideas about life based on what we know from biological, philosophical and physical facts. They’ll discuss whether a singular definition of life is possible or even relevant – could such an approach blind us to finding something more profound?

We hope this conversation will shed light on what we are, living beings searching for an explanation to differentiate ourselves from a rock or a star. And perhaps we’ll open our minds to possibilities beyond a simple definition of life.

Dr. Haley Sapers

Dr. Haley Sapers received her PhD as a Canada Vanier Scholar in Planetary Science at Western University in Canada on the roles of impact crating on the origin, evolution, and preservation of life. She completed postdoctoral work at UBC, McGill, Caltech, and JPL. Haley was a Human Frontier in Science Program postdoctoral fellow working jointly between the University of Southern California, the California Institute of Technology, and the NASA Jet propulsion laboratory where she worked with Mars 2020 SHERLOC team, experimenting with deep UV Raman in biological systems. Dr. Sapers is currently a Research Associate in Planetary Exploration and Astrobiology and the interim director of the Planetary Volatiles Laboratory York University, Toronto, Canada where she works with Prof. John Moores testing novel methods of measuring methane to improve our understanding of near-surface atmospheric chemistry on Mars.  She is also a collaborator on the Mars Science Laboratory (Curiosity Rover) science team. Haley holds a visiting scientist position at the California Institute of Technology where she is involved in studying the structure and architecture of deep subsurface microbial communities 4850’ underground at the Sanford Underground Research Facility and in ocean floor methane seeps. Haley studies the biotic-abiotic interface understanding how this dynamic system changes over space and time with implications for early life on Earth, deep subsurface microbial communities, and the search for life beyond Earth. Her research on meteorite impact cratering as a fundamental geological process in planetary evolution highlights the role cratering plays in creating, maintaining, and preserving habitability.

Carol Cleland

Carol Cleland is Professor of Philosophy and Director of The Center for the Study of Origins at the University of Colorado Boulder. Carol is also a SETI Institute affiliate. She specializes in the philosophy of science. Her research interests include scientific methodology (historical science and the field sciences considered generally the role of anomalies in scientific discovery, and the concept of an historical natural kind in mineralogy), scientific theories and the use of models (especially in the historical sciences), philosophy of biology (microbiology, astrobiology, nature and origin(s) of life, and the hypothesis of a ‘shadow biosphere,’ a term which she coined). She has published in major scientific journals (e.g., PNASGeology, and Astrobiology) as well as top-ranked philosophy journals (British Journal of Philosophy of SciencePhilosophy of Science, and Biology and Philosophy). She is the author of The Quest for a Universal Theory of Life: Searching for life as we don’t know it and Co-Editor (with Mark Bedau) of The Nature of Life: Classic and Contemporary Perspectives from Philosophy and Science.  She is currently working on a new book on the role of anomalies in scientific discovery. 

Sponsored by Wendi Zhang


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