Sarah Walker
speaker
510 appearances
1 recordings
1 series
first heard Jun 2024
last heard Jun 2024
Sarah Walker’s voice in public audio — every appearance, attributed to the second.
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Did you see this in the jungle?
Yeah, but it can't erase it. It's just restructuring it. And I think the other thing that is really vivid to me about this example that you're giving is how much death is necessary for life. So I worry a bit about notions of immortality and whether immortality is a good thing or not. So I have sort of a broad conception that life is the only thing the universe
generates that actually has even the potential to be immortal. But that's as like this sort of process that you're describing where life is about memory and historical contingency and construction of new possibilities. But when you look at any instance of life, especially one as dynamic as what you're describing, it's a constant birth and death process.
But that birth and death process is like the way that the universe can explore what possibilities can exist and Not everything, not every possible human or every possible ant or every possible zombie ant or every possible tree will ever live. So it's, you know, it's an incredibly dynamic and creative place because of all that death.
Yeah, it does. I think the thing that's perplexing for me about these kind of examples is, you know, effectively the ant's dead, but it's staying alive now because it's piloted by this fungus. And so that gets back to this, you know— thing that we were talking about a few minutes ago about how the boundary of life is really hard to define.
So, you know, anytime that you want to draw a boundary around something and you say, this feature is the thing that makes this alive, or this thing is alive on its own, there's not ever really a clear boundary.
And these kind of examples are really good at showing that because it's like the thing that you would have thought is the living organism is now dead, except that it has another living organism that's piloting it. So the two of them together are are alive in some sense, but they're, you know, now in this kind of weird symbiotic relationship that's taking the sand to its death.
I think we have to get rid of the notion of an individual as being relevant. And this is really difficult because, you know, a lot of the ways that we think about life, like the fundamental unit of life is the cell. Individuals are alive. But we don't think about how how gray that distinction is. So, for example, you might consider
you know, self-reproduction to be the most defining feature of life. A lot of people do actually like, you know, one of these standard different definitions that a lot of people may feel like to use in astrobiology is life as a self-sustaining chemical system capable of Darwinian evolution, which I was once quoted as agreeing with. And I was really offended because I hate that definition.
I think it's terrible. And I think it's terrible that people use it. I think like every word in that definition is actually wrong as a descriptor of life.
Yeah, I know. If you want to make me angry, you can pretend I said that and believed it.
Yeah, they're all interesting words. Um, And, you know, together they sound really smart and they sound like they box in what life is, but you can use any of the words individually and you can come up with counterexamples that don't fulfill that property. The self-sustaining one is really interesting thinking about humans, right? Like we're not self-sustaining. We're dependent on societies.
And so, you know, I find it paradoxical that, you know, it might be that societies, because they're self-sustaining units, are now more alive than individuals are. And that could be the case, but I still think we have some property associated with life. I mean, that's the thing that we're trying to describe. So that one's quite hard. And in general, you know, no organism is really self-sustaining.
They always require an environment. So being self-sustaining is coupled in some sense to the world around you. We don't live in a vacuum. So that part's already challenging. And then you can go to chemical system. I don't think that's good either. I think there's a confusion because life emerges in chemistry, that life is chemical. I don't think life is chemical.
I think life emerges in chemistry because chemistry is the first thing the universe builds where it cannot exhaust all the possibilities because the combinatorial space of chemistry is too large.
Yes.
Oh, sure. Or maybe. I don't know.
Where the – very precisely, it's not the first thing it creates. Obviously, like, it has to make atoms first. But it's the first thing. Like, if you think about, you know, the universe originated, atoms were made in, you know, Big Bang nuclear synthesis and then later in stars and then planets formed and planets become engines of chemistry. They start exploring what kind of chemistry is possible.
Okay. And the combinatorial space of chemistry is so large that even on every planet in the entire universe, you will never express every possible molecule. I like this example actually that Lee gave me, which is to think about taxol. It has a molecular weight of about It's got, you know, a lot of atoms, but it's not astronomically large.
And if you tried to make one molecule with that molecular formula and every three-dimensional shape you could make with that molecular formula, it would fill 1.5 universes. So with one unique molecule. That's just one molecule. So chemical space is huge.
Showing 21–40 of 510 · page 2 of 26
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