you open the book Life as No One Knows It: The Physics of Life's Emergence with a distinction between the materialists and the vitalists. So what's the difference? Can you maybe define the two? I think the question there is about whether life can be described in terms of matter and physical things, or whether there is some other feature that's not physical that actually animates living things. So for a long time, people maybe have called that a soul. It's been really hard to pin down what that is. So I think the vitalist idea is really that it's kind of a dualistic interpretation. That there's sort of the material properties, but there's something else that animates life, that is there when you're alive, and it's not there when you're dead. And materialists kind of don't think that there's anything really special about the matter of life and the material substrates that life is made out of. So they disagree on some really fundamental points. Is there a gray area between the two, like maybe

all there is is matter, but there's so much we don't know that it might as well be magic. That, like whatever that magic that the vitalists see, meaning like there's just so much mystery that it's really unfair to say that it's boring and understood and as simple as, quote, unquote, physics. Yeah, I think the entire universe is just a giant mystery. Um, I guess that's what motivates me as a scientist. And so often times when I look at open problems like the nature of life or Consciousness or you know what is intelligence or are there souls or whatever whatever question that we have that we feel like we aren't even on the tip of answering yet. I think, you know, we have a lot more work to do to really understand the answers to these questions. So it's not magic, it's just the unknown. And I think a lot of the history of humans coming to understand the world around us has been taking ideas that we once thought were magic or Supernatural and really understanding

them in a much deeper way. Um, that we learn what those things are, and they still have an air of mystery even when we understand them. There's, there's no, there's no sort of bottom to our understanding. So, do you think the vitalists have a point that they're, uh, more eager and able to notice the magic of life? I think that no tradition, vitalists included, is ever fully wrong about the nature of the things that they're describing. So, a lot of times when I look at different ways that people have described things across human history, across different cultures, there's always a seed of Truth in them. And I think it's really important to try to look for those because if there are narratives that humans have been telling ourselves, uh, for thousands of years, for thousands of generations, there must be some truth to them, you know. We've been learning about reality, um, for a really long time, um, and we recognize the patterns that reality presents us. We don't always understand what those patterns are, and so I think

it's really important to pay attention to that. So I don't think the vitalists were actually wrong. And a lot of what I talk about in the book. But also I think about a lot just professionally is the nature of our definitions of what's material. And how science has come to invent the concept of matter. And that some of those things actually really are inventions that happened in a particular time in a particular technology. That could learn about certain patterns and help us understand them. And that there are some patterns we still don't understand. And if we knew how to uh measure those things. Or we knew how to describe them uh in a more rigorous way. We would realize that the material world matter has more properties than we thought that it did. And one of those might be associated with the thing that we call life. Life could be a material property. And still have a lot of the features that the vitalist thought were mysterious. So we may still expand our understanding what is Incorporated in the category of matter that will eventually incorporate.

such magical things that the vitalists have noticed like life. Yeah, so I think about um, I always like to use examples from physics, so I'll probably do that to like. Like, it's just my, it's my go-to place. Um, um, but you know, in the history of gravitational physics, for example, in the history of motion, you know, like when Aristotle came up with his theories of motion, he did it by the material properties he thought things had. So, there was a concept of things falling to Earth because they were solid, and things raising to the heavens CU they were air like, and things moving around the planet CU they were Celestial like. But then we came to realize that thousands of years later, and after the invention of many technologies that allowed us to actually measure um, um, time in a mechanistic way, and track planetary motion, uh, and we could, you know, roll balls down incline planes and track that progress, we realized that if we just talked about mass and acceleration, we could unify all Motion in the universe in a really simple

description um so we didn't really have to worry about the fact that my cup is heavy and the air is light like the same laws describe them um if we have the right material properties to talk about what those laws are actually inter ING with and so I think the issue with life is we don't know how to think about information in a material way and so we haven't been able to build a unified description of what life is or the kind of things that Evolution builds um because we haven't really invented the right material concept yet so when talking about motion the laws of physics appear to be the same everywhere in the universe you think the same as true for other kinds of matter that we might eventually include life in I think life obeys Universal principles I think there is some deep underlying exploratory framework that will tell us about the nature of life in the universe and will allow us to identify life that we can't yet recognize um because it's too different you write about the Paradox of defining

life. Why does it seem to be so easy and so complicated at the same time? You know, all the sort of classic definitions people want to use just don't work. They don't work in all cases. So, uh, Carl Sean had this wonderful essay on definitions of life where I think he talks about aliens coming from another planet. If they saw Earth, they might think that cars were the dominant life form because there's so many of them on our planet and like humans are inside them. And you might want to exclude machines, uh, but any definition, you know, like classic biology textbook definitions would also include them. So, you know, he wanted to draw a boundary between, uh, these kind of things by trying to, uh, exclude them, but they were naturally included by the definitions people want to give. And in fact, what he ended up pointing out is that all of the definitions of life that we have, whether it's life is a self-reproducing system or life eats to survive or life requires compartments, whatever it is, there's always a counter example that challenges that definition.

this is why viruses are so hard or why fire is so hard and so uh we've had a really hard time trying to pin down from a definitional perspective exactly what life is

Does the soul exist? | Sara Walker and Lex Fridman

Clips from the Lex Fridman podcast. Visit the main channel for full conversations and other videos.