Life, free energy, and the pursuit of goals
Many Minds
You've probably come across the "free energy principle." It's become one of the most influential ideas in the broader cognitive sciences. Since the neuroscientist Karl Friston first introduced it in 2005, the theory has been fleshed out, extended, generalized, criticized, and cited thousands and thousands of times. But what is this idea, exactly? What does it say about the nature of brains and minds? What does it say about the phenomenon of life itself? And is anything that it says really that new? My guest today is . Kate is a philosopher at the University of Edinburgh and the author of the...
info_outline
Universal emotions in fact and fiction
Many Minds
Are human emotions universal? Or do they vary from one place to the next and from one time period to the next? It's a big question, an old question. And every discipline that's grappled with it brings its own take, its own framings and forms of evidence. Some researchers appeal to cross-cultural experiments; others turn to neuroimaging studies or conceptual analysis. Some even look to fiction. My guest today is , an Associate Professor of English Literature at Arizona State University. Brad is the author of a new book, ; in it he maps the landscape of debate around this long-contested topic....
info_outline
From the archive: Fermentation, fire, and our big brains
Many Minds
Hi friends, We're taking care of some spring cleaning this week. We'll be back in two weeks with a new episode. In the meantime, enjoy this favorite from our archives! - The Many Minds team ––––––––– [originally aired February 22, 2024] Brains are not cheap. It takes a lot of calories to run a brain, and the bigger your brain, the more calories it takes. So how is it that, over the last couple million years, the human brain tripled in size. How could we possibly have afforded that? Where did the extra calories come from? There's no shortage of suggestions out there. Some say...
info_outline
Howl, grunt, sing
Many Minds
The tree of life is a noisy place. From one branch come hoots and howls, from another come clicks and buzzes and whines. And coming from all over you hear the swell of song. But what is all this ruckus about? Why do so many animals communicate with sound? What kinds of meaning do these sounds convey? And—beyond the case of human speech—do any of these sounds merit the label of “language”? My guest today is , a zoologist at Cambridge University. Arik is an expert on vocal communication across the animal kingdom and the author of the recent book . Here, Arik and I talk about why the...
info_outline
The development of evolution
Many Minds
Evolution is not what it used to be. A lot has changed since Darwin's day. In the first half of the 20th century, evolutionary theory was integrated with an emerging understanding of genetics. Late in the 20th century, biologists started taking seriously the idea that organisms don't just adapt to their environments, they change them. Recently, researchers have started to acknowledge the role of culture in evolutionary processes. And so slowly our understanding of evolution has been reconsidered, updated, expanded. And more updates are underway. But it's not just our understanding of evolution...
info_outline
String theories
Many Minds
Where would our species be without string? It's one of our most basic technologies—so basic that it's easy to overlook. But humans have used string—and its cousins rope, yarn, cordage, thread, etc.—for all kinds of purposes, stretching back tens of thousands of years. We've used it for knots and textiles and fishing nets and carrier bags and bow-strings and record-keeping devices. It's one of the most ubiquitous, flexible, and useful technologies we have. But we haven't only put string to practical purposes. We've also long used it to tickle our minds. My guest today is . Roope is a...
info_outline
The other half of the brain
Many Minds
Neurons have long enjoyed a kind of rock star status. We think of them as the most fundamental units of the brain—the active cells at the heart of brain function and, ultimately, at the heart of behavior, learning, and more. But neurons are only part of the story—about half the story, it turns out. The other half of the brain is made up of cells called glia. Glia were long thought to be important structurally but not particularly exciting—basically stage-hands there to support the work of the neurons. But in recent decades, at least among neuroscientists, that view has faded. In our...
info_outline
A paradox of learning
Many Minds
How do we learn? Usually from experience, of course. Maybe we visit some new place, or encounter a new tool or trick. Or perhaps we learn from someone else—from a teacher or friend or YouTube star who relays some shiny new fact or explanation. These are the kinds of experiences you probably first think of when you think of learning. But we can also learn in another way: simply by thinking. Sometimes we can just set our minds to work—just let the ideas already in our heads tumble around and spark off each other—and, as if by magic, come away with a new understanding of the world. But how...
info_outline
From the archive: The octopus and the android
Many Minds
Happy holidays, friends! We will be back with a new episode in January 2025. In the meantime, enjoy this favorite from our archives! ----- [originally aired Jun 14, 2023] Have you heard of Octopolis? It’s a site off the coast of Australia where octopuses come together. It’s been described as a kind of underwater "settlement" or "city." Now, smart as octopuses are, they are not really known for being particularly sociable. But it seems that, given the right conditions, they can shift in that direction. So it's not a huge leap to wonder whether these kinds of cephalopod congregations could...
info_outline
Your brain on language
Many Minds
Using language is a complex business. Let's say you want to understand a sentence. You first need to parse a sequence of sounds—if the sentence is spoken—or images—if it's signed or written. You need to figure out the meanings of the individual words and then you need to put those meanings together to form a bigger whole. Of course, you also need to think about the larger context—the conversation, the person you're talking to, the kind of situation you're in. So how does the brain do all of this? Is there just one neural system that deals with language or several? Do different...
info_outlineForests have always been magical places. But in the last couple decades, they seem to have gotten a little more magical. We've learned that trees are connected to each other through a vast underground network—an internet of roots and fungi often called the "wood wide web". We've learned that, through this network, trees share resources with each other. And we've learned that so-called mother trees look out for their own offspring, preferentially sharing resources with them. There's no question that this is all utterly fascinating. But what if it's also partly a fantasy?
My guest today is Dr. Justine Karst. Justine is a forest ecologist at the University of Alberta. Her research focuses on mycorrhizas—these are the symbioses formed between fungi and plant roots that are thought to be the basis of the "wood wide web." Last year, Justine and colleagues published a perspective piece in which they argued that some of the claims around the wood wide web have gotten out of hand. These new ideas about forests, they argued, have gotten decoupled from the actual on-the-ground—or under-the-ground—science. In reality, it’s a field still riddled with unknowns and mixed findings.
Here, Justine and I do a bit of mycorrhiza 101—we talk about what mycorrhizas are, how they evolved, and what the structures actually look like. We discuss the original 1997 study that inspired the term "wood wide web." We consider why it's so hard to figure out what's actually going on, mechanistically, under the forest floor. We discuss the increasingly popular notion of plant intelligence and what it means to empirical researchers in this area like Justine. We talk about why people—both members of the public and scientists themselves—have found wood wide web ideas so charming. And, finally, we discuss the question of whether a little bit of hype is really so bad—particularly if it gets people excited about forests, about science, and about conservation.
I got as excited about the "wood wide web" as anyone. The idea totally captured my imagination a couple of years ago. So I was intrigued—if also a little dismayed—to learn recently that these ideas were getting some pushback. And I knew immediately we should talk to one of the researchers leading that pushback.
Alright friends, let's get to it. On to my conversation with Dr. Justine Karst. Enjoy!
A transcript of this episode is available here.
Notes and links
5:00 – Popular treatments sometimes mentioned as over-hyping the wood wide web (and associated ideas) include The Hidden Life of Trees, Finding the Mother Tree, and the novel The Overstory.
9:30 – The landmark 1997 paper by Simard et al. that kicked off interest in the so-called wood wide web.
11:00 – A study showing that fungi are more closely related to animals than to plants.
11:30 – For more on the new interest in “plant intelligence” see our previous episodes here and here. On the notion of “fungal intelligence,” see here.
18:00 – A 1975 paper presenting a hypothesis about the origins of land plants.
20:00 – The California “mushroom bible” mentioned.
23:00 – A brief post (and infographic) on the differences between arbuscular mycorrhizas and ectomycorrhizas.
23:30 – Richard Powers’ influential novel, The Overstory. Note that the novel doesn’t exclusively focus on the wood wide web; it covers ideas and findings about trees and forests, many of which are uncontroversial.
36:00 – Dr. Karst co-authored her perspective piece in Nature Ecology & Evolution with Dr. Melanie Jones and Dr. Jason Hoeksema.
50:00 – For more on aspens and how they constitute clonal organisms, see here.
52:00 – The “mother tree” idea was popularized in Dr. Suzanne Simard’s book, Finding the Mother Tree.
1:04:00 – Another recent critique of the wood wide web and mother tree idea is here. In it the authors write: “Reaching out to the general public to make people care about forests is certainly a praiseworthy goal, but not when it involves the dissemination of a distorted view of the plant world. In other words: the end does not justify the means.”
1:05:30 – Others influenced by The Overstory include Barack Obama and Bill Gates.
1:09:00 – A primer on myco-heterotrophic plants.
1:13:00 – See a recent presentation by Dr. Jared Farmer on trees and “chronodiversity” here.
Recommendations
‘Seeing plants anew,’ Stella Stanford
‘Mother trees and socialist forests: Is the ‘wood-wide web’ a fantasy?’, Daniel Immerwahr
Many Minds is a project of the Diverse Intelligences Summer Institute, which is made possible by a generous grant from the John Templeton Foundation to Indiana University. The show is hosted and produced by Kensy Cooperrider, with help from Assistant Producer Urte Laukaityte and with creative support from DISI Directors Erica Cartmill and Jacob Foster. Our artwork is by Ben Oldroyd. Our transcripts are created by Sarah Dopierala.
Subscribe to Many Minds on Apple, Stitcher, Spotify, Pocket Casts, Google Play, or wherever you listen to podcasts. You can also now subscribe to the Many Minds newsletter here!
We welcome your comments, questions, and suggestions. Feel free to email us at: [email protected].
For updates about the show, visit our website or follow us on Twitter (@ManyMindsPod) or Bluesky (@manymindspod.bsky.social).