What Are The Weirdest Types Of Life? - Carl Zimmer | Modern Wisdom Podcast 394

Carl Zimmer is a science writer, journalist and an author who specialises in the topics of evolution, parasites, and heredity. Life is the thing which illuminates our corner of the universe. It gives colour to an otherwise cold, brutal void. But what is life? How is it defined? Despite seeming obvious at first glance, this question is one of the most contested in science. Expect to learn what are the most extreme forms of life which can live in the vacuum of space, how life might have begun in rock pools, why aliens might be so different to us that we don't even recognise them, how a slimemould that looks like dog vomit can learn its way through a maze and much more... Sponsors: Join the Modern Wisdom Community to connect with me & other listeners - https://modernwisdom.locals.com/ Get 20% discount on the highest quality CBD Products from Pure Sport at https://puresportcbd.com/modernwisdom (use code: MW20) Get perfect teeth 70% cheaper than other invisible aligners from DW Aligners at http://dwaligners.co.uk/modernwisdom Extra Stuff: Buy Life's Edge - https://amzn.to/3pZZLZx Follow Carl on Twitter - https://twitter.com/carlzimmer Get my free Reading List of 100 books to read before you die → https://chriswillx.com/books/ To support me on Patreon (thank you): https://www.patreon.com/modernwisdom #biology #extremophiles #life - 00:00 Intro 00:38 Our Awareness of Life 10:09 What Constitutes Life & Death? 20:45 Animals with Weird Ideas About Life & Death 25:48 Understanding Life for Fungi 34:21 Other Forms of Life in the Universe 40:16 Origins of Life on Earth 44:48 Are Viruses Alive? 50:13 Discovering a Better Definition of Life 57:10 Where to Find Carl - Join the Modern Wisdom Community on Locals - https://modernwisdom.locals.com/ Listen to all episodes on audio: Apple Podcasts: https://apple.co/2MNqIgw Spotify: https://spoti.fi/2LSimPn - Get in touch in the comments below or head to... Instagram: https://www.instagram.com/chriswillx Twitter: https://www.twitter.com/chriswillx Email: https://chriswillx.com/contact/

Carl ZimmerguestChris Williamsonhost

Nov 5, 202157mWatch on YouTube ↗

WHAT IT’S REALLY ABOUT

Carl Zimmer Explores Life’s Strangest Forms And Redefines Being Alive

Carl Zimmer and Chris Williamson explore why defining “life” and “death” is so scientifically and philosophically messy, despite how intuitively obvious they seem to humans and other animals.
They examine edge cases—cryptobiotic tardigrades, shape-shifting snakes, maze‑solving slime molds, death-aware primates, and ambiguous entities like viruses—that challenge standard biological definitions.
The conversation extends to weird possible alien life (silicon, non‑water solvents), competing theories of life’s origins on Earth, and medical complexities like brain death and organ donation.
Zimmer concludes that instead of arguing over static definitions, science needs a true theory of life, akin to how chemistry replaced pre‑modern “definitions” of water with molecular understanding.

IDEAS WORTH REMEMBERING

5 ideas

Definitions of life are fragmented and context-dependent.

Biologists, philosophers, and agencies like NASA all use different working definitions, revealing that “life” serves multiple purposes—from medical decision-making to astrobiology—and resists a single, tidy description.

Basic life–death recognition is widespread in animals and deeply intuitive in humans.

Species from fish to primates adjust behavior around corpses or biological motion, and humans possess a felt sense of being alive that can break down in rare conditions like Cotard Syndrome, where people insist they are dead.

Some organisms effectively pause life, challenging metabolism-based definitions.

Cryptobiotic species such as tardigrades can dry out, vitrify their internal components into a protein “glass,” halt detectable metabolism for decades, then fully revive—defying simple alive/dead binaries.

Intelligence and memory don’t require brains or bodies like ours.

Slime molds, single giant cells without nervous systems, solve mazes, optimize paths between food sources, and use chemical “trails” as an externalized memory, showing that problem-solving is a general feature of life, not just brains.

Medical definitions of death are partly social and ethical constructs.

The adoption of brain death criteria, driven in part by organ transplantation needs, demonstrates that when biological states are ambiguous, societies negotiate where to draw the line between life and death.

WORDS WORTH SAVING

5 quotes

You could argue that we don’t really have a deep conceptual understanding of life either.

— Carl Zimmer

Life doesn’t really care about our absolutes that way.

— Carl Zimmer

They’re just on pause, and can stay on pause for decades, maybe centuries.

— Carl Zimmer (on cryptobiotic tardigrades)

You don’t need a brain to be intelligent because these slime molds are literally solving math problems with no need of a brain.

— Carl Zimmer

Don’t try to define life. Definitions are pointless… What we really need is a theory of life.

— Carl Zimmer, summarizing philosopher Carol Cleland

Why definitions of life and death are inconsistent and controversialAnimal and human perception of life, death, and disorders like Cotard SyndromeCryptobiosis and organisms that blur the line between life and non-life (e.g., tardigrades)Extreme metabolisms and unusual life strategies (snakes, slime molds, fungi-like organisms)Primate thanatology and evolutionary roots of death awareness and ritualWeird and hypothetical life: alien biochemistry, non-water solvents, silicon-based systemsOrigins of life on Earth and the debate over viruses being aliveThe case for a theory of life instead of formal definitions, and historical failures at “life’s edge”

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