You know, we like to think we.

Understand what makes something alive. DNA, evolution, natural selection, the usual suspects. But what if I told you that cells from your own trachea sitting in a petri dish right now could spontaneously organize into swimming robots that heal brain tissue? What if frog skin cells, with no genetic modification whatsoever could build copies of themselves from spare parts lying around? This isn't science fiction. This is the work of Michael Levin at Tufts University. And it's completely rewriting the rules of biology.

So we took cells from adult human patients, tracheal epithelial cells. Turns out that they, too come together and form these little motile creatures. We call them ant robots. Those guys have 9,000 differently expressed genes, and they can do cool things like they can heal neural wounds. This is just the tip of the iceberg.

Michael Levin's research challenges our fundamental understanding of what life is and where biological properties emerge from. Michael Levin is a distinguished biologist at Tufts University and director of the Allen Discovery center, whose groundbreaking research on bioelectricity and regenerative biology is reshaping our understanding of how biological systems process information and pursue goals.

Is xenobots, living robots built from frog.

Cells swim around, work together, and reproduce in ways that have never existed on Earth. What does this tell us about consciousness, intelligence, and the nature of life itself?

Professor Michael Levin, welcome to the into the Impossible podcast.

Thank you for having me. It's great to see you.

We have so many questions. We'll run out of time before we run out of questions, I'm sure. But I want to first start with the big picture question. Why is electricity, of all the fundamental forces of nature, nuclear forces, strong and weak gravitation, why is it that electric and not, say, magnetism, plays such an outsized role when we know that electricity and magnetism are unified via Maxwell's equation? So why does electricity play a bigger role than, say, these magnets here that I have on my desk do?

It is certainly the case that living tissue is sensitive to magnetic fields, electromagnetism. Ultra weak photons are important. All of these things are important. I have no idea if biology can harness the stronger than or the weak force. I just don't know.

Maybe.

I don't know. But the special thing about electricity at this point is the following. It is a really convenient modality to serve as what I call cognitive glue. There are other things that do it. There are other things that could do it elsewhere in the universe. I'm sure it's done by other mechanisms if there's life elsewhere. But here's the thing that evolution loves about bioelectricity, it's a very convenient way to make electrical networks out of subunits, so group subunits into bigger things in a way that allows the whole to have goals, memories, preferences, and basically problem solving behavior that the individual pieces don't have. It allows a raising of levels, so to speak.

And we can go into great detail how it does it. But basically the exact same thing that electricity is doing in your brain, which makes you more than the sum of, than just a pile of neurons. It has been doing that for bodies, multicellular bodies, long before neurons ever came on the scene. It's a way to scale up the cognitive light cone of materials.

Basically, we'll get to the cognitive light con because it's impossible for a physicist that's like, you know, bait for a physicist to evoke Einstein and all sorts of other things. But before I get there, you know, when I think about electricity, when I think about it as a physicist, I don't normally associate it with things that are squishy. And unless, you know, somebody threw a toaster in the bathtub, and that would be quite dangerous, obviously we're not recommending that. But talk about how electricity even arises, and on what scales does it manifest? I mean, we don't see little anodes and cathodes or, you know, positive and negative terminals on cells. So how does it instantiate itself in a mechanistic way? And you could be very technical. I mean, my audience is, you know, one of the most magnificent and mindful in the known multiverse. So talk us through. How is a.

How is a cell like a battery or a magnet with these kind of polarities and dipoles and everything associated with it?

Yeah, no, cells absolutely have charged particles that, that typically ions of potassium, sodium chloride, and things like this. And, and the best way to anchor these kinds of discussions is by thinking about what happens in neuroscience. So we understand that our cognition is underwritten by the bioelectricity that operates in individual neurons and then in groups of neurons and other cells in the brain. So what happens is you have cells and in their plasma membrane, which is basically this lipid kind of membrane that's usually a pretty good insulator. What evolution has discovered are special kinds of proteins called ion channels. And these ion channels have really interesting properties where they let certain charged species like potassium chloride, sodium, and so on. They either preferentially let them in or out of the cell. And as a result, what you end up with is a voltage gradient.