#198 – Sara Walker: The Origin of Life on Earth and Alien Worlds
Jul 9, 2021
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Sara Walker, an astrobiologist and theoretical physicist, dives into the mysteries of life's origins and the intriguing possibility of extraterrestrial life. She discusses the RNA world hypothesis and the role of hydrothermal vents in life's early emergence. The conversation also explores concepts like the shadow biosphere and panspermia, questioning how we define life. Walker highlights innovative strategies for detecting alien life, emphasizing a holistic understanding of biological complexity. Her insights intertwine philosophy with science, reflecting on existence and our place in the universe.
RNA and DNA played crucial roles in relaying genetic information and catalyzing reactions in the early Earth's conditions.
Life must be viewed as a planetary phenomenon, requiring similar conditions to Earth for existence on other celestial bodies.
Life emerges from an interplay of causal histories and possible futures, governed by an underlying physics of information and emergence.
Experimental validation for the origin of life involves reducing information input to observe emergent properties and patterns reflecting information seeding.
Exploration of consciousness and its physical impact on events raises questions about subjective experience and neural correlates beyond basic biological markers.
Deep dives
Nature of Life's Origin
The podcast delves into the various hypotheses surrounding the origin of life on Earth, focusing on the RNA world scenario and the metabolism hypothesis. The RNA world scenario suggests that molecules like RNA and DNA played vital roles by relaying genetic information and catalyzing reactions. The metabolism hypothesis emphasizes the role of energy sources and catalytic cycles in early Earth's geochemistry to kickstart self-organization and eventually life's evolution.
Implications of Planetary Phenomena on Life
The discussion highlights a conceptual shift to view life as a planetary phenomenon intricately linked to planetary processes and cycles. It suggests that for life to exist on other planets like Mars, these planets must be modified to resemble Earth's conditions, indicating the reproduction of Earth-like environments on other celestial bodies for life to thrive.
Speculations on the Laws of existence
The podcast delves into the search for a fundamental physics explanation for existence, suggesting that life emerges from a unique interplay of causal histories and possible futures. It postulates that the laws of physics shall reveal themselves differently at the chemical level due to the combinatorial complexity, implying an underlying physics that governs information and emergence.
Experimental Validation of Origination
Experimental validation for the origin of life focuses on reducing information input in experiments to observe emergent properties without human bias. The podcast discusses the interaction of complex chemical objects seeded into lower causal systems and the emergence of patterns mirroring information seeding. It advocates for probing spontaneous information emergence to elucidate life's mysteries.
Questioning the Nature of Consciousness and Subjective Experience
The discussion delves into the concept of subjective experience, posing questions about whether physical systems with subjective experience can cause events that wouldn't occur otherwise. This inquiry attempts to address the problem of consciousness and its potential impact on interactions with the world, implying that consciousness may have physical consequences.
Neural Correlates of Consciousness and Chemical Correlates of Life
Drawing parallels between the search for neural correlates of consciousness and the search for chemical correlates of life, the podcast explores how neuroscience investigates consciousness through correlates like verbal reports. It highlights the challenge of linking neural correlates to consciousness and the approach of 'faking it till making it'. Contrasting with astrobiology's focus on molecules in biology, neural correlates delve into understanding consciousness beyond basic biological markers.
Life, Determinism, and Randomness in Understanding Existence
Discussions center around life's intricate patterns and assembly processes, suggesting a novel approach to detecting life by examining high assembly structures. The conversation navigates determinism and randomness in life's evolution, pondering the fundamental questions of life's necessity in the universe. With a focus on the physics of life, the discourse explores the underlying causal histories that shape existence and the potential interplay between determinism, randomness, and free will in understanding life's origins and essence.
Exploring the Origin of Aliens Among Us
The podcast touches on the fascinating concept that there could be alien life forms with a different origin event coexisting on Earth alongside us. This idea challenges the assumption of a single common ancestor for all life on our planet. Scientists like Paul Davies have proposed that alternative life forms could be present, possibly in the shadows, awaiting discovery among us. The discussion highlights the potential scientific and philosophical implications of finding evidence of multiple distinct life origins on Earth.
Contemplating Consciousness, Existence, and the Meaning of Life
The conversation delves into complex topics such as consciousness, existence, and the meaning of life. It considers the role of interactions between humans, robots, and other entities in creating consciousness. The discussion explores the connection between creation and beauty, suggesting that the universe's creative processes may be intertwined with the intrinsic sense of beauty. Participants ponder existential questions, including the significance of life's existence and the emotional responses triggered by intellectual endeavours and creative pursuits.
Sara Walker is an astrobiologist and theoretical physicist interested in the origin of life. Please support this podcast by checking out our sponsors:
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OUTLINE:
Here’s the timestamps for the episode. On some podcast players you should be able to click the timestamp to jump to that time.
(00:00) – Introduction
(07:44) – Origin of life
(15:38) – Did aliens seed life on Earth?
(20:48) – What is life?
(32:27) – Cellular automata
(36:56) – The laws of physics may change with time
(46:41) – Nobel Prize for the origin of life
(52:01) – Is consciousness fundamental to the universe?
(1:03:19) – Life is the most deterministic part of physics
(1:05:54) – Free will
(1:14:11) – How to detect alien life
(1:28:48) – How many alien civilization are out there?
(1:35:32) – Shadow biosphere
(1:41:59) – UFO sightings
(1:45:35) – Exponential population growth of AI lifeforms
(1:52:42) – The role of death in life
(1:56:45) – Advice for young people
(2:02:31) – Meaning of life
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