Sara Walker: Physics of Life, Time, Complexity, and Aliens | Lex Fridman Podcast #433

So, you have an original life event. It evolves for four billion years, at least, on our planet. It evolves a technosphere. The technologies themselves start having this property we call "life", which is the phase we're undergoing now. It solves the origin of itself and then it figures out how that process all works, understands how to make more life, and then can copy itself onto another planet, so the whole structure can reproduce itself.

The following is a conversation with Sarah Walker, her third time on this podcast. She is an astrobiologist and theoretical physicist interested in the origin of life and in discovering alien life on other worlds. She has written an amazing new upcoming book titled Life As No One Knows It: The Physics of Life's Emergence. This book is coming out on August 6th, so please go pre-order it now. It will blow your mind. This is the Lex Fridman Podcast. To support it, please check out our sponsors in the description, and now, dear friends, here's Sarah Walker. 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, you know, 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- 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?

(laughs)

That- that, like, whatever that magic that the vitalists see.

Yeah.

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, oftentimes 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.