In this engaging discussion, Sara Walker, a theoretical physicist and astrobiologist at Arizona State University, explores the origins of life from a unique perspective. She delves into assembly theory, discussing how complexity and information play crucial roles in life's emergence. Listeners will be captivated by her insights into the nature of randomness and chaos, and how these concepts impact our understanding of intelligence in the universe. Sara also tackles the Fermi Paradox, pondering why we haven’t detected extraterrestrial life despite the vast cosmos.
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question_answer ANECDOTE
Sara's Career Shift to Abiogenesis
Sara Walker shifted from theoretical physics to origins of life through her PhD advisor Marcelo Gleiser's interest in astrobiology.
This shift grew from foundational questions about life's big unknowns to a committed career focus in the field.
insights INSIGHT
Theory Hard to Vary is Key
Good scientific theories have broad explanatory power and are hard to vary, meaning they can't be tweaked arbitrarily and still hold.
This contrasts with mere data-fitting; true understanding requires theories embedded in measurable physical reality.
insights INSIGHT
Limits of Miller-Urey Chemistry
The classic Miller-Urey experiment showed abiotic synthesis of amino acids but resulted in messy carbon tar when prolonged.
Without selection, chemical combinatorial explosion creates complex but non-living mixtures, illustrating limits of simple prebiotic chemistry.
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Stuart Kauffman's "The Origins of Order" is a seminal work in complexity science, exploring the principles of self-organization and selection in biological evolution. The book introduces the concept of autocatalytic sets, networks of molecules that can collectively reproduce themselves, as a potential mechanism for the origin of life. Kauffman argues that order and complexity can emerge spontaneously from simple systems, challenging traditional views of biological evolution. He emphasizes the role of feedback loops and emergent properties in shaping the development of complex systems. The book has significantly influenced the field of complexity science and continues to inspire research on the origins of life and the nature of biological organization.
Life as No One Knows It
The Physics of Life's Emergence
Sara Imari Walker
In 'Life as No One Knows It,' physicist and astrobiologist Sara Imari Walker argues that solving the origin of life requires radical new thinking and an experimentally testable theory for what life is. This is an urgent issue for efforts to make life from scratch in laboratories and missions searching for life on other planets. Walker proposes a new paradigm for understanding what physics encompasses and what we recognize as life, culminating in a bold proposal for a new theory for identifying and classifying life that applies to any instance of life in the universe. The book celebrates the mystery of life and the explanatory power of physics.
The Urgence of Everything
Harold Morwitz
Jim talks with Sara Walker about the ideas in her new book Life as No One Knows It: The Physics of Life's Emergence. They discuss Sara's path from theoretical physics to astrobiology, the biggest scientific questions, philosophy of science & theory development, historical approaches to origin of life research, Schrödinger's negative entropy concept, Prigogine's dissipative systems, information as a causal force at life's origin, emergence as a scientific concept, constructor theory of information, Assembly Theory as a framework for detecting life, assembly index & copy number as measurable properties, complexity vs randomness, the physical nature of time in complex systems, how Assembly Theory redefines life beyond Earth-centric definitions, planetary-scale perspectives on life's origins, measurements of exoplanet atmospheres, addressing the error catastrophe problem, Sara's collaboration with Lee Cronin, the application of Assembly Theory to minerals & planetary atmospheres, the Fermi Paradox & observational horizons, constraints on Drake equation parameters, and much more.
Episode Transcript
Life as No One Knows It: The Physics of Life's Emergence, by Sara Walker
JRS Currents 100 - Sarah Walker and Lee Cronin on Time as an Object
The Emergence of Everything: How the World Became Complex, by Harold Morowitz
The Origins of Order: Self-Organization and Selection in Evolution, by Stuart Kauffman
Sara Walker is a theoretical physicist interested in the origins of life and discovering alien life on other worlds. She is Deputy Director of the Beyond Center for Fundamental Concepts in Science, a Professor in the School of Earth and Space Exploration at Arizona State University and an External Faculty at the Santa Fe Institute. Her recognition as a leading scientist includes a Stanley Miller Early Career award, and a Schmidt Sciences Polymath award. Her research team at ASU is internationally regarded for their work at the forefront of building fundamental, and testable theory for understanding what life is. She is also widely regarded for her public intellectual work advancing our understanding of life, which includes her popular science book Life as No One Knows It: The Physics of Life’s Emergence and appearances on podcasts such as Star Talk with Neil de Grasse Tyson, the Joe Rogan Experience, and the Lex Fridman podcast.
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