May 5, 2023 06:59 PM
https://www.quantamagazine.org/a-new-the...-20230504/
EXCERPT: . . . These and other missions on the horizon will face the same obstacle that has plagued scientists since they first attempted to search for signs of Martian biology with the Viking landers in the 1970s: There is no definitive signature of life.
That might be about to change. In 2021, a team led by Lee Cronin of the University of Glasgow in Scotland and Sara Walker of Arizona State University proposed a very general way to identify molecules made by living systems — even those using unfamiliar chemistries. Their method, they said, simply assumes that alien life forms will produce molecules with a chemical complexity similar to that of life on Earth.
Called assembly theory, the idea underpinning the pair’s strategy has even grander aims. As laid out in a recent series of publications, it attempts to explain why apparently unlikely things, such as you and me, even exist at all. And it seeks that explanation not, in the usual manner of physics, in timeless physical laws, but in a process that imbues objects with histories and memories of what came before them. It even seeks to answer a question that has perplexed scientists and philosophers for millennia: What is life, anyway?
Not surprisingly, such an ambitious project has aroused skepticism. Its proponents have not yet made clear how it might be tested in the lab. And some scientists wonder whether assembly theory can even deliver on its more modest promises to distinguish life from nonlife, and to think about complexity in a new way.
Assembly theory evolved, in part, to capture Lee Cronin’s suspicion that “complex molecules can’t just emerge into existence, because the combinatorial space is too vast.”
But others feel that these are still early days for assembly theory, and there’s a real chance that it might bring a fresh perspective to the question of how complexity arises and evolves. “It’s fun to engage with,” said the evolutionary theorist David Krakauer, president of the Santa Fe Institute. Assembly theory, he said, offers a way to discover the contingent histories of objects — an issue ignored by most theories of complexity, which tend to focus on the way things are but not how they got to be that way. Paul Davies, a physicist at Arizona State agrees, calling it “a novel idea with the potential to transform the way we think about complexity.” (MORE - missing details)
EXCERPT: . . . These and other missions on the horizon will face the same obstacle that has plagued scientists since they first attempted to search for signs of Martian biology with the Viking landers in the 1970s: There is no definitive signature of life.
That might be about to change. In 2021, a team led by Lee Cronin of the University of Glasgow in Scotland and Sara Walker of Arizona State University proposed a very general way to identify molecules made by living systems — even those using unfamiliar chemistries. Their method, they said, simply assumes that alien life forms will produce molecules with a chemical complexity similar to that of life on Earth.
Called assembly theory, the idea underpinning the pair’s strategy has even grander aims. As laid out in a recent series of publications, it attempts to explain why apparently unlikely things, such as you and me, even exist at all. And it seeks that explanation not, in the usual manner of physics, in timeless physical laws, but in a process that imbues objects with histories and memories of what came before them. It even seeks to answer a question that has perplexed scientists and philosophers for millennia: What is life, anyway?
Not surprisingly, such an ambitious project has aroused skepticism. Its proponents have not yet made clear how it might be tested in the lab. And some scientists wonder whether assembly theory can even deliver on its more modest promises to distinguish life from nonlife, and to think about complexity in a new way.
Assembly theory evolved, in part, to capture Lee Cronin’s suspicion that “complex molecules can’t just emerge into existence, because the combinatorial space is too vast.”
But others feel that these are still early days for assembly theory, and there’s a real chance that it might bring a fresh perspective to the question of how complexity arises and evolves. “It’s fun to engage with,” said the evolutionary theorist David Krakauer, president of the Santa Fe Institute. Assembly theory, he said, offers a way to discover the contingent histories of objects — an issue ignored by most theories of complexity, which tend to focus on the way things are but not how they got to be that way. Paul Davies, a physicist at Arizona State agrees, calling it “a novel idea with the potential to transform the way we think about complexity.” (MORE - missing details)