The larger conversation about consciousness is so interesting because we don't have definitions for consciousness in ourselves-or at least we don't have a knowledge of the mechanical basis for our own consciousness, nor even how to definitively define something as conscious.

It's all this kind of wavy stuff around consciousness and many theories.

Some people say consciousness can only be verified by the ability to knock someone unconscious-like, our ability to be put under, in a way.

And remarkably that test also works on plants.

You can etherize a plant-diethyl ether works on plants.

So in general, plants are moving around all the time, slower than we mostly can see.

But in time-lapse, like, a little pea plant will be, like, waving its tendrils around all the time and curling and uncurling them.

And if you put a pea plant under a bell jar with diethyl ether, they will, like, grind to a halt when researchers removed ether, within 15 minutes, they kind of go back to dancing around again.

And what's happening there, they found in other plants, like Venus flytraps, is that their electrical pulses are reducing, which is also what we see in ourselves: the electrical activity in our bodies also goes down when we're under the influence of anesthetics.

And similarly we don't really know the mechanism for why anesthetics works on us.

So these mysteries of consciousness-even in ourselves-are so intriguing, especially when we're trying to draw really hard lines in the sand between who has it and who doesn't.

Yeah, hearing stories like that, it's easy to see how some people have gotten carried away with the idea of plant intelligence and taken it too far, which is something you get into quite a bit in the book.

I mean, the biggest danger in writing about this is that it gets flattened into some cartoonish version of itself, where, like, plants are little humanoid creatures, and that's definitely not what I'm trying to do at all.

And (it's) in part because this whole book is haunted by a book that came before it in 1973 called The Secret Life of Plants, which many people probably remember.

And it's the reason people play classical music to their plants or think that plants like classical music more than rock and roll.

There's a famous chapter in this book about how a former CIA agent hooked up a polygraph test to a plant and then thought about setting this plant on fire and claimed that the polygraph went wild, which implied the plant was reading his mind.

Lot of levels there-polygraphs: not accurate.

And then when that couldn't be replicated, he said it was because you have to have a good rapport with your plant for it to work.

It's the perfect excuse.

The vibes have to be good. And the damage that book did to the field was immense.

The funding agencies sort of closed the doors to research on plant behavior.

It was a very embarrassing moment because you have this, like, unleashed on the popular imagination.

It was very sticky. Everyone was talking about it.

And there was so much in there that it was not reproducible science.

And so we don't want to jump that gun.

And it's like, this is a field in tremendous flux right now; we don't have settled answers as to the full extent of what plants can do or what we should make of this.

But there is a lot of incredible, fully peer-reviewed research coming out that is bringing up these questions of, "How should we regard the fact that they have ... plastic, responsive decision-making abilities or they can communicate and things like that- they can detect their kin?"

Thinking back to, when you were just becoming aware of this field, do you remember what your initial reactions were to papers that got into the idea of plant intelligence and behavior?

I felt very skeptical toward them.

I called several of the people behind these papers and several people who very strongly disagree with them.

And I think people on all sides have really valid points.

I mean, I think the most valid point is that, like, "Should we even evaluate plants according to human notions of intelligence?"

It's hard for us to dislocate our sense of intelligence away from the extremely human and, like, sometimes even academic version.

But I was also intrigued because what happens if we can hold in mind the fact that plants are so incredibly other, that they diverged from our evolutionary branch so long ago as to be basically aliens to us, but to imagine how intelligence might have formed under the evolutionary pressures that they experienced and that it would be very different from what we'd expect of ourselves or even of mammals or in general-or animals in general but that that could still-whatever that was could still be a form of consciousness because they evolved under the same evolutionary pressures we did?

And why should we assume we're the only ones to have gotten it?

It reminds me of animal-cognition researchers who say, "If you want to figure out how to communicate with aliens one day, the perfect place to start is studying how animals communicate-nonhuman animals-because it requires really figuring out how to peel away biases about how cognition works or what communication is that we might not even realize we have."

So I feel, like, with plants that it's that times 10 at least. Exactly. Yes, doesn't get really more other than plants.

Totally.