Life as No One Knows It
The Physics of Life's Emergence, Sara Imari Walker
Hi, I’m Aastha, and welcome to Live Longer World, where I interview scientists researching the frontiers of longevity science and write about health & longevity practices.
"The fundamental unit of life is not the cell, nor the individual, but the lineage of information propagating across space and time." "We need to focus not on what life is made of, but on how the universe acquires the information to make it." - Sara Imari WalkerThe origin of life is one of the most exciting and perplexing questions to ponder. Darwin gave us answers to the evolution of life. But how did life begin in the first place?
Sara Imari Walker attempts to answer this question by looking at the physics behind life’s emergence. She says that in order to understand life we need a new physics. This is a bold hypothesis which involves the creation of a new branch of physics, and theories at the intersection of biology, physics, and astrobiology.
This has lent her to collaborate across disciplines with top minds like David Deutsch, Michael Levin, Lee Cronin, Paul Davies, and Chiara Marletto.
Understanding the origin of life is not merely a theoretical problem - it can have vast implications involving the creation of new life, and our regeneration capabilities for longevity.
Below are some notes from her book, Life As No One Knows It - The Physics of Life’s Emergence. You can also watch her interview with Joe Rogan should these notes pique your interest.
For the practical longevity folks out there, heads up that this post is more on the side of the frontiers of biology.
These notes were first posted on X as a thread. I’ve kept the thread format below given it makes for an easier read.
What is life? Philosophers and scientists have been asking this question for aeons. Schrodinger’s famous book What is life has inspired many others to explore this question. Yet we have no answer.
“We cannot derive life from the known laws of physics, even if we are pretty sure it must be consistent with them.” Perhaps we need to reframe the question from What is life to Life is what??
Three hard problems: Origin of life is not the only hard problem. There are 2 more that plague both scientists and philosophers. The three are origins of mind, origins of matter, origins of life.
“The hard problem of consciousness: that existing feels like something (at least for us). The hard problem of matter: that nothing can be observed to exist outside of interactions. The hard problem of life: that abstractions (information) matter in determining what can exist.”
All 3 hard problems are linked to one fundamental question: “Why do some things exist (or experience existence) and not others?"
We need a new physics to understand life. To do so, Sara Imari had to narrow in on the key problem of life. “Which aspects of life will prove too stubborn in our attempts for reduction to known physics and chemistry. That is, we wanted to identify the property that constitutes a candidate for the hard problem of life.” And that question is: “How is it that information can cause things?”
“The challenge is how to make the concept of information physical, such that we can recognize how it matters to matter.” “This is a key feature of information – it can be copied between very different things. This is why we call information “abstract”: it seems not to depend on the physics of the substrates you store it in or access it from.” Genes are the prototypical example of this in biology. This concept of information is inspired by David Deutsch and Chiara Marletto's constructor theory.
"Focusing on the problem of what can exist and when resolves much of the ambiguity about the causal power of information – that information can cause things to happen. Saying information is causal merely points to the fact that some things that come to exist require something that already exists to assemble them. Some require longer chains of causation and thus are more “informational”.
Assembly theory: “With our work on assembly theory, we are not attempting to define life. Instead our aim is to provide a formalism for unifying life and the inanimate. How can we uncover the physics that gives rise to life and allows the transition from nonlife to life to even happen?”
“The new physics needed to explain life starts with understanding what exists and why. That is, it starts with selection of, and for, what gets to exist as physical objects.”
“Life is the only thing in the universe that can make objects that are composed of many unique, recursively constructed parts. Assembly theory – theory of physics that considers life’s objects as fundamental.”
“To get to a testable theory, we are doing something unusual: we are working backwards. We’re asking what we can measure about molecules in the lab that would indicate when they are objects that can emerge only via selection and evolution.”
Origin of life scam: "The fundamental unit of life is not the cell, nor the individual, but the lineage of information propagating across space and time." "We need to focus not on what life is made of, but on how the universe acquires the information to make it."
"Our aim was to shift the focus of approaches to the origins of life from traditional prebiotic chemistry to how the combination of theoretical advances, artificial life, messy chemistry, and new ideas about information and matter could energize progress."
Universal constructor: Lee Cronin's company Chemputer is working on a universal constructor for all chemical spaces they have explored so far in the chemistry lab. The hope is to scale this up to search large volumes of chemical space all at once.
Summarizing: Sara Imari is working on a new theory of physics known as Assembly theory to understand the emergence of life. It hinges on the problem of what can exist and the information that can cause things to happen.
I’ll admit that it’s hard to summarize such a book or understand the depth of it through notes and quotes, so if you’re interested pick it up.
I’ll be back with some writing on understanding cancer soon.
To living longer,
I'm really not sure about this. I do not know enough to refute the long, detailed, rather critical review of the book on Amazon.co.uk.