What Is Life? A podcast about the really, really big questions

What Is Life? was supported by a grant from Science Sandbox, a Simons Foundation initiative.

Listen to all eight episodes via Apple, Stitcher, Spotify, or wherever you get podcasts.

In 2017, Carl Zimmer hosted a series of talks about the nature of life before a live audience at Caveat in New York. You can listen to these conversations with eight leading thinkers at the links below. You can also subscribe to all eight episodes on iTunes, via RSS, etc. If you like them, please rate and review them! 

For a deeper exploration of these subjects, check out Zimmer’s new book, Life’s Edge: The Search For What It Means To Be Alive. 


Episode 1. Carlos Mariscal: What Do We Mean When We Ask, “What Is Life?”

Carlos Mariscal

Carlos Mariscal is a philosopher at the University of Nevada Las Vegas. He collaborates with evolutionary biologists and astrobiologists to explore what it means to be alive. When we ask what is life, Mariscal suggests, we may be asking the wrong question.

Carlos Mariscal at UNLV
“Life and Only Life: A Radical Alternative to Life Definitionism.” Synthese 2018. You can grab this paper, and others, on Mariscal’s research page.


Episode 2. Sara Walker: If We Find Alien Life, Will We Even Know It?

Sara Imari Walker is a physicist and astrobiologist at Arizona State University. She studies life as a physical phenomenon, in order to develop new ways to search for it elsewhere in the universe. We shouldn’t assume that aliens will introduce themselves to us, so we need a way to recognize life no matter what form it takes.

Walker at ASU
Walker’s TEDx talk about a “universal theory of life.”


Episode 3. Jim Cleaves: The Origin of Life, from Frankenstein to a Laboratory Spark

In this episode, I spoke to H. James Cleaves, a professor at the Earth-Life Science Institute in Tokyo and co-author of A Brief History of Creation: Science and the Search for the Origin of Life. Today, the origin of life is a scientific question that researchers around the world are trying to answer. But, as Cleaves explains, virtually no one thought of this particular question 200 years ago. It took some visionaries — including Mary Shelley, the author of Frankenstein — to shift our view of life to something that could arise through natural processes.

Cleaves at ELSI
A Brief History of Creation


Episode 4. Caleb Scharf: How Did Life Begin?

We don’t know how life got its start. But as more evidence emerges, explains astrobiologist Caleb Scharf, only a few theories are emerging as leading contenders. Scharf is the director of the Columbia Astrobiology Center at Columbia University.



Episode 5. Jeremy England: Why Does Life Exist?

In this episode, I spoke to Jeremy England, a physicist at MIT,  about why life exists. He has developed an influential theory of life as a way for matter to dissipate energy.

England’s MIT lab site
An article about England in Quanta


Episode 6. Steven Benner: How Weird Can Life Get?

In this episode, I talked with Steven Benner, a scientist at the Foundation for Applied Molecular Evolution, about how strange life can get. All the life we know is the same: carbon-based, with DNA for genes. (Okay, except for RNA viruses.) But Benner says we should remain open to the possibility that life elsewhere is very, very weird.

Benner at FFAME
An article I wrote about Benner for the New York Times


Episode 7. Donato Giovannelli: Warm Ponds Or Hellish Vents–Where Did Life Begin?

Donato Giovannelli is an assistant professor at the University of Naples “Federico II.” He travels to acid lakes and other extreme environments that are the closest thing today to what Earth was like when life began.

Giovannelli’s web site
Giovannelli on Twitter


Episode 8. Kate Adamala: Can We Make Life?

Kate Adamala is a chemist at the University of Minnesota. In her Protobiology Lab, she is trying to build a synthetic cell from scratch.

 Protobiology Lab
 Adamala’s TEDx talk, “Life But Not Alive”