Carl Zimmer in Seed Magazine
It’s a peculiar state of affairs—biologists have learned more in the past decade about how living things work than we’ve learned collectively over the past several centuries—and an intense debate has arisen over what to do about it. Some are skeptical of science’s ability to come up with a definition of life that’s accurate enough to be meaningful, while others believe a definition is not just possible but essential for the future of biology.
“A science in which the most important object has no definition—that’s absolutely unacceptable,” says Popa. “How are we going to discuss it if you believe the definition of life has something to do with DNA and I think it has something to do with dynamic systems? We cannot have a conversation on any level. We cannot make artificial life because we cannot agree on what life is. We cannot find life on Mars because we cannot agree on what life represents.”
Recently, a new voice has entered the debate. Carol Cleland, who teaches philosophy at the University of Colorado and works with the NASA Astrobiology Institute—essentially as their philosopher-in-residence—is making a more radical argument: Scientists should simply give up looking for a definition of life. They can’t even begin to understand what life really is, she claims, until they find forms of life profoundly different from those we know here on Earth. Only when we can compare alien life with life on our planet will we understand the true nature of this ubiquitous, ephemeral thing.