One of the greatest scientists of the 20th century, Freeman Dyson, is as much known for his significant contribution to science as he is for courting controversy throughout his life. Over six decades, he built a body of work that sits alongside some of the most renowned physicists, mathematicians, and intellectuals of our time.

On closer inspection, it feels as if Dyson has lived a double life. On the one hand, playing the role of philosopher, and on the other, a scientist labouring over some of mathematics’ most complex problems, all without a PhD we might add. In the latter part of the 20th century, Dyson became known for espousing some incredibly speculative and wonderful ideas, from the enormously imaginative Dyson sphere to the equally inspiring Dyson Tree, both sparking fierce debate amongst sci-fi circles across the world. But what he has become most known for in the last decade is his ability to uphold his heretical views on climate change. His belief that climate change is happening, yet we do not have an idea as to why or how has irritated the scientific community to no end. Nearing his centenary years, Freeman Dyson now heads into the tailwind of another controversy. This time, it’s Darwin’s widely accepted theory around evolution that is his target. At 94, Dyson is ready to defy the status quo once again.

One of the things I like a lot about you is that you’re not afraid to disagree even in the face of the status quo. Your close colleague Steve Weinberg said about you, “Freeman Dyson will do his best to chip at the ice”. Where do you think you got that particular trait from? I suppose it started out when I was quite a small kid. In England where I grew up, there were the people who went shooting with guns and playing a lot of football, that was the majority, and then there was the minority who were people like me who spent their time reading books. We always felt ourselves to be an endangered species. I was always used to being part of a threatened minority when I was young and I suppose that lasted.

"Huge crowds of Japanese people were silently following us wanting to touch the wheelchair, they thought there was some magic in it." Freeman Dyson on physicist Stephen Hawking

I guess what I’m asking is, is it important to you to not accept things at face value? Yes. Of course, I read a lot of sceptics. The people I read most as a teenager were Robin Holliday, the biologist, and Bertrand Russell and Alfred Whitehead. These were all heretics in one way or another. Looking at the contributions that you, Niels Bohr, Robert Oppenheimer and Albert Einstein have made to our culture, do you worry that they perhaps contributed negatively just by looking at their nuclear legacy? Yes of course I do, but I wouldn’t call that negative. Of course, they’re all different, but I think they all made very positive contributions, Einstein in particular. I mean he was a real politician as well as a scientist, he knew how to play to the crowd, and he did it very well.

I would say, anybody that takes an important part in politics particularly and military affairs, has to make hard choices. So no matter how it comes out you always regret something, and you might have done better.

A colleague of Dyson, J. Robert Oppenheimer (pictured) carried the legacy of the nuclear bomb into his life. Freeman, do you think that the egos of scientists sometimes get in the way of doing good work? Yes. I would say quite frequently. On the other hand, the ego also helps. It goes both ways. It makes people overconfident and inclined to believe things that are nonsense, and on the other hand, it gives them the confidence to go boldly into the future. So you need both. If you were awarded the Nobel Prize for something in your career, what particular achievement do you think would be fitting? I didn’t ever earn a Nobel Prize, that’s not my style. I have a short attention span, I solve problems for fun, but I don’t think deep thoughts about nature. I don’t think any of my work is of Nobel quality. Of the achievements in the scientific body of knowledge in the last few decades, which Nobel Prize would you say has been the most distinctive to you? Well, of course, I think of the ones that were not given. It was a scandal that Stephen Hawking did not get the Nobel prize; he should’ve had it thirty years ago. And every year I waited to see if Stephen would get it and he never did. That was a scandal. I don’t know why people didn’t value his work; he was a great scientist as well as being a great human being. Did you meet him? Yes. I mean this is, of course, a digression, but I happened to be staying in a hotel in Tokyo, and Stephen Hawking was there also in the same hotel. And he said he would like to go for a walk to see what Tokyo looked like, so I said I’d be happy to come with him. So we went, him in his wheelchair, and we walked through the streets of Tokyo and huge crowds of Japanese people were silently following us wanting to touch the wheelchair, they thought there was some magic in it. The Japanese people worshipped him like a god. I found that delightful and of course Stephen enjoyed it too; he had a sense of humour, so he played up to the crowd, just like Einstein.

“It’s still to me very mysterious that humans are so capable.” Photo by Verena Huber-Dyson, Pontresina, Switzerland, June 1954 I can imagine they have similar traits. The first time that I heard about you, with my limited technical proficiency in science, I was fascinated and intrigued by the idea of the Dyson Sphere. And I think it’s an idea that has captured the imagination of pop culture. Well, it’s a joke actually. It was a misunderstanding. I used the word biosphere which means habitat for aliens.

I was proposing searching for heat radiation which would be an indication of an advanced civilisation somewhere in the sky, so we should look with infrared telescopes for heat radiation and that what we’re looking for is a significant habitat in which the aliens might be living.

But I called it a biosphere and somehow that was misunderstood as a big round ball which had nothing to do with that. So the whole thing was rubbish. But of course, it was a serious proposal to look for this infrared radiation, and that was done about twenty years later. The original plan was proposed in 1960 I think and around 1980 we had a little satellite telescope in the sky, called the IRAS (the infrared astronomy telescope) which did the first sky survey looking for heat radiation. Of course, the joke is that we found the sky crawling with these objects. There are millions of these objects in the sky, and the problem is they’re all natural because what they are is very young stars condensed out of dust clouds, so they still have the dust around them. Instead of shining with visible light, what you see is, in fact, heat radiation from the dust. So the search for aliens was not a success. But we’re still equally looking for that anomaly. I’m not sure if you’ve heard of Tabby’s star. I have indeed, that’s another piece of hype of course. It’s an exciting mystery, but the sky is full of mysterious objects that we don’t understand. You have to observe for several years usually to find out what’s going on. With Tabby’s star, it’s exciting but it’s nothing very startling, and it’s been brutally exaggerated. Why do you say that? If it elicits the observation of many scientists why do you say it’s an exaggeration? I mean the way it’s discussed on the internet and in popular literature, it’s regarded as something extraordinary but it’s not. It’s one of many such objects that we see, and gradually you discover what’s going on.

“If we don’t understand ice ages we don’t understand climate.” – on the mystery of climate change. Freeman, I want to put a quotation to you, “science can bring you to the Big Bang, but it can’t take you beyond it, you need a different kind of apparatus to peer into that”. Do you think that the mysteries of the world can be answered by science alone? No, it certainly does not come down to science. We have all kinds of sources of knowledge: literature, history, art, architecture, all kinds of wonderful things that are part of human culture that we need in order to find our place in the universe. Not just science, science is a small part of it. It happens to be going ahead very fast just in recent years. But religion, of course, is also important, and religion is much deeper in our culture than science. As you look through the long lens of science and the history and the culture that it’s brought us and the understanding of our universe, how do you view humanity’s progress and development as a species? Well, I would say it’s sort of miraculous how well we’ve done and it’s still to me very mysterious that humans are so capable. If you just look at the struggle for existence in the last million years when most of the time we were living in caves with ice ages coming and going, it was a very tough and rugged existence most of the time. And in order to survive that why did we need Beethoven and why did we need Shakespeare? It’s quite amazing that our cultural lives are so rich compared with how we were living in caves. The important invention in a way for the human species was grandparents. Grandparents were the beginning of culture when we could sit around the cave fire and the grandparents would sing songs to the children and the parents would be out hunting. So having three generations was what made us what we are. I want to ask you about another proposal you made besides the Dyson Sphere. It’s an idea that you talked about a while ago that potentially intelligent beings may be capable of thinking an infinite number of thoughts in an open expanding universe. Do you know which proposal I’m talking about? Yes well, of course in those days when I wrote that, about thirty years ago, everybody then believed that the universe is expanding linearly with a constant velocity of a given object. And now we know that the universe is accelerating – that’s the discovery of the last ten years – and in an accelerated universe everything is different so that whole discussion, in fact, is now wrong. I don’t think we know enough about the accelerating universe to go over it and see how it’s changed. Are you saying that due to the idea that the universe is accelerating it potentially changes your idea about how we think and the capability of thinking? Yes. In a very drastic way. It’s bad news if we really are accelerating all the time in the future.

“I regard it as a huge mystery on a level with the origin of life.” – Dyson on consciousness Photo by Verena Huber-Dyson, Zürich, Switzerland, August 1951 Is consciousness a word which is particularly attractive to you? Is it something that keeps you up? It’s certainly an interesting mystery. I regard it as a huge mystery on a level with the origin of life. All the big mysteries like the origin of the human species are things we don’t understand, and consciousness is one of the biggest and we understand it least in a way. I think the key should be studying babies. The real mystery is what is going on in the head of a six-month-old baby that enables the baby to make sense of all the things that are going on around it. So if we can somehow study the brains of babies in real detail, we might get a feeling for how consciousness begins. But of course, we are very far away from being able to do that. If it was thirty years ago and you were just as speculative in your proposals, what is something that you would perhaps propose today that you’ve been sitting on? I’m thinking a lot about evolution at the moment. It happens that I corresponded with two heretics on the subject of evolution. Motoo Kimura who was a Japanese biologist and Ursula Goodenough, an American biologist. Both of them had heretical ideas about evolution which I think were probably correct. I’m preparing a talk which discusses the idea that Darwin was correct up to a point but he didn’t tell us the whole story. Because the biologists are very defensive about Darwin. If you say anything critical about Darwin you’re regarded as an enemy. It’s a very dangerous subject to tread on. I kept quiet for thirty years so maybe it’s time to speak. Just to clarify here for our readers, obviously, you’re poking holes in Darwin’s Theory of Evolution but you’re saying it only tells the story up to a certain point. What do you mean by that? Well that he believed that evolution was driven by selection. That’s essentially Darwin’s contribution. And it’s true for big populations, but it has limits. The limits are you need big populations in order for selection to be dominant. If you have small populations, then random drift is actually more important than selection. That’s the Kimura theory. Kimura called it the neutral theory of evolution and he wrote a book about it which was widely ignored by all the orthodox biologists. But I think he was right. And in fact, it happens that small populations are very important in evolution. In fact, you have to have a small population to start a new species, almost by definition. So small populations have a controlling effect on starting new species and also in the extension of old species. So this neutral regime where the selection is not important may, in fact, be the real driving force of evolution when you come to a new species. And of course, if that’s true, it changes the picture in many ways.

"If you say anything critical about Darwin you’re regarded as an enemy." Dyson on the theory of evolution

What do you think Richard Dawkins would make of this? I mean let him speak for himself, but he is generally very dogmatic that selection dominates, and he talked about the selfish gene which is correct of course if you have a big population. If you have small populations, not so much, genes come and go mostly by random chance. Darwin understood the difficulty. He asked the question “why is nature so diverse?”, he asked, “why do we have millions of species?” Darwin asked the question, in a beautiful way, “why did God love beetles? There are half a million species of beetles, why did God make so many?” And it’s hard to understand that on the basis of selection. If selection were dominant, then you’d expect that there would be a few species of beetle which would prevail. They would be the best adapted and the others would disappear. But in the real world, you have this enormous richness of species, many kinds of beetle and there are birds of paradise and there are all sorts of weird peacocks with peacock feathers which seem to be peculiarly unfit. And all those weird creatures which have prevailed for reasons that Darwin couldn’t explain. He understood that there was a problem and I think that the neutral theory of Kimura really does help a lot to understand that. Let’s move to another area, you’ve become known for questioning climate change. The idea that there has been a 40% rise in CO2 over 130 years, that’s not something you disagree with.

But you do disagree with this idea that the climate is predictable or we know why it is happening. Is that correct? Yes. I mean we don’t understand climate. The most extreme examples of climate change were the ice ages and they were really a catastrophe for life in many parts of the world. And we don’t understand them. We just don’t know why they started or why they come and go in a more or less periodic fashion. It’s all a big mystery. And if we don’t understand ice ages we don’t understand climate. So to counteract the rise in CO2 what has been your suggestions to the scientific community? Well, the only paper I’ve written on the subject, in the official literature, was recommending growing trees. In fact, we could grow enough trees to take care of the carbon in the atmosphere. And that’s still true. If you planted all the wasteland over the globe with trees, it would be just about enough to absorb the carbon from the atmosphere. The carbon in trees is about equal to the carbon in the atmosphere. So the trees could be a way of managing the climate up to a point. Do you believe that we face an imminent crisis on earth and that the pandemonium that seems to be sweeping the public, the media and the scientific community is appropriate? No, I don’t. It is starting to subside I would say. I don’t read much of what’s published but I have the feeling that the point of view of the sceptics is being listened to a bit more now than it was.