David: Can we go back to reductionism? You said you felt that there was… we’d come to the end of that particular kind of science. What did you…?

MG: I wouldn’t say that. No, I don’t think you can…

David: What did you…?

Ard: There’s a danger of reductionism, at least?

MG: Reductionism has been physics’ best friend, in the sense that it’s been so useful as a way of making sense of what’s going on, because what it does is if you have something very complicated, you break it into little bits, study the little bits, put things back together again and hope that the total is the sum of its parts.

And the ultimate goal of reductionism, of course, is to reduce everything to the simplest possible components. So this notion goes all the way back to atomism, the old notion of atomism from Greece, where matter is made of little things, and hence you just have to put them back together again like Lego, like little Lego blocks.

Ard: So reductionism is this idea that you can break it into the parts, but the whole is nothing more than the sum of the parts?

MG: Exactly. And that’s true for many systems. But it gets harder when the systems are not so well-behaved and they have many, many interacting parts.

But there is a place for reductionism in science, obviously. The fact that every atom of hydrogen is the same around the universe is a triumph of reductionism. And it’s true, they are the same. There is this fundamental repetition of these basic building blocks.

And that’s why it’s been so tantalising to extend this notion to everything there is. So people have tried to do mechanistic models of pretty much the mind, and the weather, and…

David: Life.

MG: …life, and even economics. And those things just don’t do very well.

Ard: And they don’t do very well because those are things that are emergent in some way or the other?

MG: They don’t do very well because sometimes, depending on the complexity of the system, if you have a system that has many parts, they interact with one another in what we call non-linear ways. So a non-linear interaction is if you kick, a rock it kicks you back in the same way. In a non-linear world with non-linear forces a small stimulus can create a huge effect, and vice versa. So it becomes much harder to predict the behaviour of a system which has many parts doing that at the same time.

The thing about reductionism is that it tries to make the universe into a big machine, like clockwork, and that is a very old idea from the 18th century, 19th century, where, if everything is mechanistic – there is this big engine behind everything – then everything is explainable and everything is predictable. This is the ultimate determinism.

And the consequence of this is that if everything is predictable, so is behaviour, so is what I’m going to say now. And that makes us a prisoner of this machine. And that tells you that you’re really not a free person: that there is no such thing as free will.

And that’s why the Romantics were so pissed off at the scientists, because they were saying, ‘Hey, it’s all a big machine.’

And they would say, ‘Wait! Wait a second. What about love and feelings and confusion and doubt? Where does that all fit into this new science you guys are talking about? That’s not the whole picture. It cannot be the whole picture.’

So that is where reductionism starts to flounder. Because, basically, it’s trying to do much more than it can, which is to predict the future in a way which is 100% accurate, and we know now that that’s not possible.

David: And is that dangerous for science, do you think?

MG: It is dangerous for science, because whenever science says that it can understand everything – including who you are, and who you’re going to be, and how you’re going to grow up – it’s robbing people of themselves. It’s basically killing their persona, in a sense, and saying, ‘You really are just a mountain of atoms, and if I know how to crank this machine, I’m just going to tell you who you are,’ and that just makes you dumb. It makes you into an automaton, and nobody wants to be an automaton.

David: It robs the world of meaning, doesn’t it? It says there’s just the machine. Someone’s turning the little handle on the machine, and it doesn’t mean anything.

Ard: Well, no one’s turning it. The machine’s just…

David: Well, it’s turning itself.

Ard: The machine’s just kind of rattling along. You may think that you’re doing something, but actually it’s the machine that’s rattling along. And so, there is no self…

David: Does it rob it of meaning?

MG: Well, it does because it basically tells you that there’s no point in searching for anything because everything is already written. There is no point in trying to understand who you are, because who you are is really pointless. It’s about electrons interacting in this big complicated way, and nobody likes that, right? I mean, you want to be able to be mysterious. People want mystery before they want reason and certainty. I think people need to not know.

Ard: But just to interject… Some people are saying, ‘Well, that may be the case that you want this, but I’m sorry for you.’

David: Yeah, grow up!

Ard: Grow up, yeah. Grow up and face the cold, hard reality that we are nothing but a bag of chemicals.

MG: Oh, we are definitely nothing but a bag of chemicals, but we have no clue how to predict how that bag of chemicals will behave.

Ard: Okay.

MG: So to say that reductionism fails doesn’t mean that there is more to it than matter. It doesn’t mean that there is some sort of soul or spirit that is controlling stuff. It just means that science cannot do that job, and I think that’s a wonderful thing.

People ask way too much of science. Some scientists, the ones that push reductionism all the way to the end, they are asking science much, more than science should be able to answer, which is to answer everything.

Science was not designed to give us all the answers. In fact, science thrives on ignorance. We need not to know in order to create new knowledge. And so this belief, because it’s nothing more than a belief, that science can probe into the behaviour of everything and come up with final answers about who you are, or even about what nature is, it’s really a misunderstanding of what science is about and how science actually operates.

Ard: But I think the argument sometimes goes like this: ‘Well, we don’t yet have a science of free will, or who you are, but we will one day. Because we didn’t used to have a science of gravity, but now we do. We didn’t used to have a science of quantum mechanics, but now we do. And so, one day we’ll have a reductionist explanation of everything in Marcelo Gleiser based on the atoms in his body.’

MG: And that to me is like a prayer. You know, like praying. You know, to me, what’s really important, right, is that we are creatures that look for meaning in everything that we do. We want to feel justified in our actions, and those scientists, you know, who are saying that there is an ultimate knowledge, that is their search for meaning.

Ard: Yeah.

MG: That’s what makes their lives meaningful. You know, if there is anything that says what is the meaning of life? Right? Well, the meaning of life is to live a life full of meaning, and that’s exactly what they are doing in their own way. So, if they believe that you can understand everything, then, that is the ultimate quest of the rational mind, and you dedicate your life to that, that is what gives them meaning, and that is awesome.

Ard: Yes.

MG: You know, good to them! And what I’m saying is that there are other ways in which we can find meaning in your life. To me, the way I look at this right now is… I look at what we learned about the universe, what we have learned about all the planets outside of Earth, what we have learned about how life evolved in this planet – and we know how rare Earth is and how rare we are as a species, an intelligent species, the, sort of, stardust that can actually think –  and that brings us back, we humans, to the centre of things. You know, not in a Copernican way, that we are the centre, but in the fact that we, like Carl Sagan said before I did, are how the universe is thinking.  And because of that, and I have my little crusade here, we should be guardians of life, and specifically of this planet.

So, to me, this new science, instead of saying, ‘Oh, the universe is enormous. We are nothing. We are just machines. We have no free will’, no, we are actually incredibly important because without us the universe wouldn’t have any meaning, because there would be no one to think about meaning in the universe.