Sara Imari Walker, an astrobiologist and theoretical physicist from Arizona State University, delves into the scientific understanding of life. They discuss how traditional definitions fall short and the intriguing role of physics in the topic. Concepts like assembly theory and the Fermi paradox come to life as they explore the potential for extraterrestrial existence. Walker also challenges us to rethink the intersection of life and technology, raising questions about whether machines could be considered alive. It's a captivating journey through the cosmos!
The inadequacy of standard definitions of life challenges our understanding, as entities like viruses and advanced systems blur the lines between living and non-living.
Understanding life as a process rooted in information rather than mere chemical composition reframes the conversation around the origin and nature of life.
The Fermi Paradox highlights the dichotomy of potential widespread extraterrestrial life existence versus the rarity of complex life forms emerging in the universe.
Deep dives
Understanding Life Through Physics
An exploration of the nature of life leads to an intriguing question: what constitutes life? The discussion references Erwin Schrödinger's significant contributions in this domain, particularly his intriguing concept of an aperiodic crystal in his book 'What is Life?' This model provides insights into genetic heredity, suggesting structures that can store vast amounts of information, akin to DNA. However, the inadequacies of standard definitions of life are also examined, highlighting grey areas, such as whether entities like viruses and technologically advanced systems can be classified as living.
The Concept of Artificial Life
The notion of artificial life poses philosophical and semantic challenges, differentiating it from artificial intelligence. While artificial intelligence refers to computational functionalities embedded within machines, the concept of instantiating life raises more profound questions. The conversation emphasizes that the distinction between biological and non-biological systems may be overly simplistic, suggesting that understanding life hinges on recognizing evolutionary continuity between them. This perspective calls into question our comprehension of life and challenges the prevalent notion that artificially created systems cannot embody life.
The Role of Information in Life
The discussion elevates the critical role of information in defining and understanding life, positing it as fundamental to the transition from non-life to life. Building on the principles of assembly theory, it is proposed that complex structures must rely on the presence of information to exist and reproduce. The boundary between life and non-life may therefore be more accurately framed in terms of information rather than merely chemical composition. This perspective emphasizes that life necessitates a causal role for information, integrating the physicality of informatics into the discussion of life's emergence.
Constructor Theory and Assembly Theory
Constructor theory offers a fresh lens to analyze physical realities by focusing on the potential tasks that can or cannot exist within the framework of physics. This contrasts with traditional physics, which prioritizes initial conditions and laws of motion. In conjunction, assembly theory characterizes the processes leading to the emergence of complex life forms as the result of systemic construction over time, revealing an intricate web of interdependent transformations. Together, these theories illuminate the significance of constructors in facilitating evolutionary processes and offer insights into the origins of life.
The Fermi Paradox and Life in the Universe
The Fermi Paradox encapsulates the tension between the vast potential for life in the universe and the absence of observed evidence. A distinction emerges between the possibility of life being common yet undetected and the notion that the emergence of complex life forms may be incredibly rare. The conversation explores potential resolutions, such as the idea of a 'great filter' that might prevent civilizations from contacting each other. Ultimately, the inquiry emphasizes the need for empirical exploration into life's origins to refine our probabilistic understanding of life's existence beyond Earth.
Sam Harris speaks with Sara Imari Walker about a scientific understanding of life. They discuss the contributions of physics to this topic, Erwin Schrödinger, the inadequacy of standard definitions of life, the prospect of "artificial" life, the role of information, constructor theory, assembly theory, the space of all possible structures, a "block universe," the existence of abstract objects like numbers, the Fermi paradox, the likelihood of life elsewhere in the universe, experiments that could decide how likely life is to emerge, the possibility of a Great Filter, the number of Earth-like worlds, and other topics.
Sara Imari Walker is an astrobiologist and theoretical physicist. She is the deputy director of the Beyond Center for Fundamental Concepts in Science and a professor in the School of Earth and Space Exploration at Arizona State University. She is also a fellow of the Berggruen Institute and a member of the external faculty at the Santa Fe Institute. She is a recipient of the Stanley L. Miller Early-Career Award for her research on the origin of life, and her research team at ASU is internationally regarded as being among the leading labs aiming to build a fundamental theory for understanding what life is. Her research has been featured in Scientific American, Quanta Magazine, and a variety of other international outlets. Her book, Life as No One Knows It: The Physics of Life's Emergence, is available now.
Learning how to train your mind is the single greatest investment you can make in life. That’s why Sam Harris created the Waking Up app. From rational mindfulness practice to lessons on some of life’s most important topics, join Sam as he demystifies the practice of meditation and explores the theory behind it.
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