August 7, 2024 • 2hr 51min

#2184 - Sara Imari Walker

The Joe Rogan Experience

In this episode, Joe Rogan interviews Dr. Sara Walker, an astrobiologist and theoretical physicist whose research focuses on the origins of life, artificial life, and the detection of life on other worlds. Dr. Walker discusses her new book "Life as No One Knows It: The Physics of Life's Emergence" and shares insights into her work on assembly theory, a new approach to understanding the fundamental nature of life and its emergence in the universe.

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Key Takeaways

Assembly theory is a new approach to understanding the origin and nature of life, focusing on how the universe generates complexity and novel structures over time
Life may be a fundamental property of the universe that maximizes the number of things that can exist, rather than just a chemical phenomenon
Our current understanding of physics is likely incomplete when it comes to explaining complex phenomena like life, mind, and consciousness
Time and causation play a crucial role in the emergence of complex structures like life, beyond just the arrangement of particles
Free will may exist as a limited ability for complex systems to navigate possibilities, rather than total freedom or pure determinism
Mathematics and infinity may be human constructs for understanding the world rather than fundamental features of reality
Expanding our understanding of life could help us recognize alien life and better understand our place in the universe

Introduction

In this episode, Joe Rogan interviews Dr. Sara Walker, an astrobiologist and theoretical physicist whose research focuses on the origins of life, artificial life, and the detection of life on other worlds. Dr. Walker discusses her new book "Life as No One Knows It: The Physics of Life's Emergence" and shares insights into her work on assembly theory, a new approach to understanding the fundamental nature of life and its emergence in the universe.

Topics Discussed

Assembly Theory and the Nature of Life (00:02)

Dr. Walker introduces assembly theory, explaining that it aims to solve the origin of life problem and aid in the search for alien life. The key ideas include:

The universe cannot generate complexity outside of living processes
There is a way to formalize and measure the complexity of objects
Life is unique in its ability to create highly complex structures

"If you see objects that require a lot of steps to make them, and they're in high abundance, life is the only thing that can make them," explains Dr. Walker.

Rethinking Life Beyond Chemistry (03:10)

Dr. Walker challenges the conventional definition of life as a purely chemical phenomenon:

Life emerges from chemistry but may represent universal physics beyond just chemical processes
Comparing life to gravity - a universal property not limited to specific materials
The need to consider non-biological forms of life like technology and AI

"I think life's kind of the same. It emerges in chemistry, but there are some informational properties, these things, about how life generates complex structures and how it does that so uniquely, that is universal physics," states Dr. Walker.

Diversity of Life and Alien Intelligence (05:56)

The conversation explores the vast possibilities for life in the universe:

Earth life represents only a tiny fraction of possible life forms
The challenge of recognizing alien life that may be radically different from Earth life
The need to expand our understanding of intelligence beyond human-like traits

"I just think the universe is far larger in the kind of living things that could exist than we can even imagine," Dr. Walker emphasizes.

Human Intelligence and Creativity (22:22)

Dr. Walker discusses unique aspects of human intelligence:

The ability to abstract, imagine, and create may be a universal feature
Humans can construct possibilities beyond what naturally exists
The importance of creativity in expanding the space of what's possible

Origin of Life Research (41:41)

Dr. Walker shares insights into current origin of life research:

No scientific consensus on how life began on Earth
Various hypotheses like RNA world, hydrothermal vents, etc.
The need to consider how Earth itself evolved to support life

"There is no consensus. None. Yeah, I know. Isn't that fun?" Dr. Walker remarks on the state of origin of life research.

Ideas as Life Forms (47:54)

Joe Rogan proposes the concept of ideas as life forms, which Dr. Walker finds intriguing:

Every physical object created by humans originated from an idea
Ideas interact and evolve like biological entities
The role of time and causation in the emergence of ideas

"I think about life as these kind of these structures that are emerging over time and generating novel things," Dr. Walker explains.

Time, Causation, and Complexity (1:10:42)

Dr. Walker elaborates on the role of time in the emergence of complex structures:

Time as a fundamental aspect of assembly theory
Complex objects have both spatial and temporal size
The universe may be expanding in possibility space over time

"You actually have an incredible amount of time in a small volume of space. That's what you are as an evolved object," Dr. Walker states.

Mathematics and Infinity (1:33:41)

Dr. Walker shares her perspective on mathematics and the concept of infinity:

Mathematics may be a physical system invented by life on Earth
Infinity as a useful concept but not necessarily a physical reality
The limitations of assuming infinite precision or resources in the universe

"I think mathematics is a physical system that exists on our planet. And I don't believe in a euclidean world that's like a perfect mathematical forms," Dr. Walker explains.

Free Will and Determinism (1:25:45)

The conversation turns to the debate between free will and determinism:

Dr. Walker's shift from determinism to a more nuanced view
Free will as emerging from the complex causal history encoded in evolved structures
The limitations of reducing complex systems to elementary particles

"Free will becomes this idea that, like you, you actually can't, you know, in standard physics, you would say like an emergent thing like us can be reduced to our atoms. And all of the fundamental description is down there. But what, what you've done is stripped that physical system of all the time inside of it," Dr. Walker explains.

The Future of Physics and Understanding Reality (2:31:16)

Dr. Walker discusses the potential for major breakthroughs in physics:

The likelihood of fundamental shifts in our understanding of reality
The need to move beyond current theories to explain phenomena like life and mind
The importance of asking "why" questions in science

"I definitely think fundamental physics has a very bright future of, like, having some really fundamentally earth shattering ways of thinking about things that I don't even think our current theories are that they're going to be replaced by things even more awesome," Dr. Walker predicts.

Conclusion

This wide-ranging conversation between Joe Rogan and Dr. Sara Walker explores cutting-edge ideas about the nature of life, the role of time and causation in the universe, and the potential for expanding our understanding of reality. Dr. Walker's work on assembly theory offers a fresh perspective on longstanding questions about the origin and nature of life, challenging conventional wisdom and proposing new ways to approach these fundamental issues. The discussion highlights the importance of continuing to ask big questions and remaining open to radical new ideas in science, even as our knowledge advances. As we seek to understand our place in the universe and potentially discover alien life, expanding our conception of what life is and how it emerges may be crucial to recognizing the full diversity of possibilities that exist.