is a theoretical physicist and best-selling populariser of science who co-founded the World Science Festival in New York.
Huw Spanner met him on 7 March 2020 on a visit to London to promote his latest book, on ‘mind, matter and our search for meaning in an evolving universe’.
Photography: Charlie Rose TV
Galileo and others spoke of ‘the Book of Nature’. If you were writing a blurb for the back cover of that ‘book’, what would you say?
The Book of Nature is written in the language of mathematics but needs to be interpreted in the language of human reflection. And it’s only by virtue of these parallel stories that you get the fullest picture of the world.
Your latest book1Until the End of Time: Mind, matter, and our search for meaning in an evolving universe (Allen Lane, 2020) is concerned with the formation of the cosmos, so it seems apt to ask you about your own formation as a thinker. When you look back at your upbringing, can you identify the key influences that shaped who you are and why you see the world as you do?
Early on it was my father, who had no formal education but had a deep interest in scientific ideas and instilled a passion for those ideas in me by teaching me some of the basics that he had picked up through his own reading.
Another vital early influence was a fellow named Neil Bellinson, who was a graduate student in the math department at Columbia University. When I was maybe 11 or 12, I exhausted the offerings of the school I attended and a teacher said: Why don’t you go to Columbia and see if there’s somebody who will take you on? (We didn’t have any money.) So, I went up there with my sister and we just knocked on doors and showed people his letter of recommendation and this one student said: Yeah, I’d be happy to teach you for free. And he took me into terrains of mathematics that I never would have encountered otherwise.
Later on, it was teachers of physics in high school and college who revealed to me that math could describe things in the real world and it was no longer about playing with numbers, it was a search for the patterns of reality. And that set me on the journey that I’ve been on ever since.
If you prove a theorem, it is just there. If you actually do prove it, it becomes one of the eternal truths of mathematics
Were you a nerdy kid?
Well, I certainly had a significant academic focus. But my dad was a composer and a voice coach2Notably of Harry Belafonte and our house was filled with his students, so I’d be working on my physics and math homework while listening to somebody singing in the next room. I think that blending of science and the arts has always been part of my intellectual DNA at some level.
Certainly now, part of what I do is abstract research,3In superstring theory and quantum geometry part of what I do is write books that try to bring these ideas to the public, but I’ve also written stage works such as Light Falls,4See 59productions.co.uk/project/light-falls. which dramatises Albert Einstein’s discovery of the General Theory of Relativity and tries to get into his head and his heart, to get into the excitement of that fundamental discovery. You want the audience to have a visceral, full-body reaction, not just a cognitive, or a nerdy-geek reaction if you will.
What routes have your siblings taken in life?
My brother went into the Hare Krishna movement and subsequently became a writer and filmmaker. He was with George Harrison in the early Seventies, I think it was, and has written a biography of him.5Here Comes the Sun: The spiritual and musical journey of George Harrison (John Wiley & Sons, 2006) My sisters are both psychologists. They’re all older than me.
It struck me, reading your book, that your sensibility is both distinctively Jewish and distinctively American.
Check and check! But my Jewish identity is cultural. Growing up, we would on occasion go to temple, but as an adult I never go. We rarely celebrate any but the highest of holidays and even that we’re not religious about, so to speak.
And distinctively American?
I share a certain outlook that the world recognises as American: an optimistic and energetic sense that all is possible, that there is the capacity in the human spirit to reach a transcendent experience.
I was thinking also of your liking for exalted language – for words such as ‘noble’ and ‘wondrous’ and ‘heroic’.
I also picked up a certain anxiety. As a student, you seem to have been preoccupied with death, at an age when most people seem to think they will live forever.
It wasn’t so much a focus on death as on doing something that will matter and make a lasting impact. In a memorable conversation, Neil Bellinson told me that if you prove a theorem, it is just there. If you actually do prove it, it becomes one of the eternal truths of mathematics.
[Similarly,] the motivation for some artists is a sense that what they are composing or sculpting or painting will outlast their own life. (Whether it will last forever is a different question!) For Bach and Brahms and any of the greats, that was certainly the case.
I am a physicalist who is committed to the notion that the rock-bottom description of reality is in terms of the most fundamental ingredients and the laws that govern them
But Bach was not concerned with his own ‘immortality’, was he? He wrote his music ‘for the greater glory of God’.
Of course, but it was music that was meant to touch on the eternal, right?
You say that as a young man you decided to specialise in mathematics because ‘I wanted to spend my life catching a glimpse of something transcendent,’ and yet at the end of the book you admit some uncertainty that mathematics ‘is fundamentally stitched into the tapestry of reality’.
Yeah. I’d say my view has become more nuanced since I was 18 or 19. Whereas at that time I really did see mathematical proofs as the kind of thing that would give you a hook on the eternal, now I recognise that there are patterns in the world that we encapsulate with a language called ‘mathematics’ that is probably of our own making, and those patterns only have significance when they are contemplated by a human brain. What do these equations and patterns mean if there’s nobody there to recognise them?
And so that has shifted my perspective on what it is that we physicists do, what it is that Einstein did, to something not that exists outside of human contemplation but rather that has its greatest representation within human understanding. And by ‘human understanding’ I really mean conscious awareness of any kind that can think about these ideas.
When all of that is gone, those patterns may still persist but they will not have the same importance because their importance is giving us (or a conscious being) insight into the nature of the world, and when there are no conscious beings left, that whole concept will have evaporated.
You describe yourself as a ‘physicalist’. What’s the difference between physicalism and materialism?
I use them pretty much interchangeably. I am a physicalist who is committed to a reductionist perspective, which is itself committed to the notion that the rock-bottom description of reality is in terms of the most fundamental ingredients and the laws that govern them.
They may be right – but I see no evidence for it. Of course, a God who wanted to remain behind the scenes could certainly construct the world in such a way that that’s all that we would have direct access to; but that isn’t a perspective that gives me much insight into the day-to-day undertakings that I find fascinating.
So, at the back of my mind I allow for the possibility that all of our research is just revealing God’s handiwork and then I move on with the investigations that I’m able to carry out, which are the ones that access observations of stars and galaxies, that access experiments of particles and fundamental laws.
Is it fair to say that you choose to be a reductionist, or do you feel that actually any scientist who thinks rigorously is bound to be one?
When I look at the power of reductionism, I feel that the perspective is so convincing that I’m surprised when people are not drawn to it. But I know clear-thinking people who are not
That’s a hard question. Ultimately it is a personal choice, but framing it that way makes it seem as though there’s a shelf-full of possibilities and you just pick the one that appeals to you the most in some aesthetic or intuitive sense – and that diminishes the perspective in a way that I think is misleading. When I look at the power of the reductionist approach to describe so much about the physical world at a level of precision that is utterly overwhelming, I do feel that the perspective is so fundamentally convincing that I’m surprised when people are not drawn to it. But I know clear-thinking people who are not.
All the same, reductionism must be blended with the insights from higher levels of organisation – atoms to cells to brains to conscious reflection – to provide a full account of reality.
It seems to me that your account of our ‘evolving universe’ identifies four great mysteries. The first – Why is there something rather than nothing? – is, surely, insoluble.
The second is: How come that ‘something’ is so comprehensively patterned (to use your term) as to produce a cosmos and not a chaos? And that ‘patterning’ is not just a pinstripe, so to speak, it’s the densest imaginable tartan.
Third, how come that patterned cosmos is so precisely configured as to produce (if only fleetingly and locally) a tiny element that is capable of contemplating it?
And fourth: How come that cosmos has proved so far to be comprehensible to that element? It’s perfectly possible to imagine that a life-form that could contemplate the universe –
Could make no headway [in understanding it]. Sure.
So, it seems to me that there are four massive hurdles before we get to where we are –
– and some would say that the idea that there is a transcendent mind that willed this outcome is so simple and so elegant and accounts for so much, it’s a wonder that so many scientists and philosophers of science are so viscerally hostile to it.
I hope it’s clear that I’m not viscerally hostile to that idea. I [just] don’t find it satisfying, because its explanatory power seems next to nothing to me. When I admit as a possibility that there’s this intelligence behind it all, I can’t do much with that. I can’t calculate the electron’s magnetic moment with that, I can’t calculate the rate of expansion of the universe from the Big Bang with that – as I can with the scientific principles we have developed that themselves do not rely on the notion that there is some intelligence behind it all.
Let’s take the first question: Why is there something rather than nothing? You have to define what you mean by ‘nothingness’, but a physicist’s definition of ‘nothingness’ suggests that it may be an unstable state, which necessarily falls apart into a ‘something’ and an ‘anti-something’ and we experience the ‘something’. I’m not saying that’s a full answer – it’s not an answer that all physicists agree upon by any stretch of the imagination – but that would feel like progress on that question; whereas simply saying that there’s something rather than nothing because a divine being willed it doesn’t give me much insight at all. And why is there this divine intelligence rather than nothing?
Oh, sure. I did suggest that the first question is impossible to answer…
It seems to me that materialists employ a kind of metaphysical homeopathy. They expunge all trace of God from their worldview but they insist on retaining some of the effects of God. For Isaac Newton, it was meaningful to say that the physical world is governed by laws, because he believed that it is the creation of an ordered Mind. All you are saying when you say it is governed by laws is that it appears to behave in a totally consistent way – but you haven’t the slightest clue why it behaves in that way, it just does.
So, that’s close to the correct perspective. The only thing that I would put differently is that when physicists use the term ‘law’, it is a mathematical articulation of patterns of physical processes that are borne out by observation and experiment to fantastic accuracy.
But you are absolutely right: if you then say to me, ‘Why is it the case that the world behaves in this regular manner?’, absolutely we say: It is a fact that we observe, and it is a beautiful fact – and we find the mathematical way to articulate that regularity and we go forward from there.
And if one day we could go further back and say, ‘This is where that mathematical law comes from,’ that would be yet more satisfying. But ascribing it to a divine lawgiver just seems to push the issue one step further back. Why did the lawgiver pick this law? Why did the lawgiver choose this regularity instead of that regularity?
When I was a boy, there were electrons, neutrons and protons, four basic forces and the vacuum of space for them to interact in. It all seemed so simple – and the great quest was to simplify it further. But in the book you remark that ‘physicists now are very happy to imagine the universe full of invisible stuff.’ There is the inflaton field,7The hypothetical field that drove the initial expansion of the universe in the Big Bang the Higgs field,8The hypothetical field that pervades space and is responsible for the mass of particles dark energy,9The hypothetical force that is believed to be causing the universe to continue to expand at an ever-increasing rate. The standard model of cosmology estimates that it makes up about 68% of the mass-energy of the universe. dark matter10Dark matter is composed of particles that do not absorb, reflect or emit light. The standard model estimates that it makes up about 27% of the universe. – and current theories posit as many as 22 extra dimensions and a potentially infinite number of universes.
You seem to be able to countenance any kind of complexity but the simple and elegant idea of a transcendent mind.
I can understand where that reaction comes from; but the important thing to keep in mind is that there are two ways to judge the complexity of a physical theory. One way to judge it is by the qualities of the world that it implies; the other way is by the simplicity and elegance of the underlying mathematical structure. I would argue that it’s very important to focus on the latter and not the former.
You need to be careful not to allow your judgement to be clouded by the richness of reality that a very simple theory can yield. If you don’t speak mathematics and you don’t come from that world, the tendency is [simply] to look at all the strange implications. The world is incredibly rich and complex – I mean, you are made of trillions of particles that are interacting, with all sorts of particles being exchanged between them in fields that affect [their] motion – and yet underneath it is a simple mathematical equation, written down by Maxwell in the 1800s.11In the 1860s the Scottish physicist James Clerk Maxwell published four equations that describe how charged particles create electric and magnetic fields.
When it comes to the possibility of extra dimensions of space, that idea naturally emerges from the field I work on, string theory. And look, we don’t know that we have the fundamental mathematical equation for string theory yet, but the equation we use as a starting-point is so simple that you could write it on a T-shirt. Moreover, the basic equations of particle physics do suggest that there are invisible fields filling space, and when we then closely examine the world we find evidence of those fields. One of the biggest discoveries of the last decade was the finding of the Higgs particle, which is a [speck] of the Higgs field, at the Large Hadron Collider in 2012. Simple math can yield the possibility of unfamiliar and hence seemingly complex qualities of reality.
The human brain has a rich repertoire of reactions to stimuli in the world, and that yields a whole variety of opinions and perspectives – and to me that’s a good thing
We talked of the notion that in humankind the cosmos has somehow developed the capacity to comprehend itself, but that is being over-generous, isn’t it? By your account, it is actually a tiny elite of people who (as you put it) ‘speak mathematics’ who can comprehend its workings.
Well, yes, point taken. But the important thing is not that everybody does comprehend its workings, not that everybody’s interested enough that they undertake the training required to understand the General Theory of Relativity and quantum mechanics; but that the human brain universally has the capacity to think about and understand these ideas.
It struck me, reading the book, that you are a bit of an elitist. When you discuss the arts, the examples you cite are the greatest masters. You quote [the US cultural anthropologist] Ernest Becker: ‘Man … sticks out of nature with a towering majesty.’12‘Man is literally split in two: he has an awareness of his own splendid uniqueness in that he sticks out of nature with a towering majesty, and yet he goes back into the ground a few feet in order blindly and dumbly to rot and disappear forever’ ( Looking around at human society today in the ascendancy of Donald Trump and others like him, do you really feel that we are so much better than other species?
Well, you know, it’s certainly the case that the human brain has a rich repertoire of reactions to stimuli in the world, and that yields a whole variety of opinions and perspectives – and to me that’s a good thing. It really speaks to the flexibility of the human mind [that] we don’t all react to things in the same way. I think that’s the power of the species. It may also be the downfall of the species…
In terms of, you know, elitism, yes, Brahms and Beethoven are masters and oftentimes looking at extreme achievements reveals something that illuminates the capacities –
But the mass of humankind is not listening to Brahms or Beethoven.
But the ability of the human mind to respond to works of art, to feel moved by music and art and sculpture and dance, that’s universal – we’ve seen it across cultures, we’ve seen it through the ages. I focus on those particular artists because they speak to me and it allows me to be genuine and not conjectural about the impact of these works. I also cite John Lennon, Leonard Cohen…
You’re evidently a cultured person and I would guess that the things you value most in life are thought, imagination, love. In your reductionist worldview, you begin with the ‘laws’ of nature, the fundamental particles and forces, and then, by an inconceivably long process, you arrive at a life-form that is capable of love, of thought, of appreciating beauty. So, the things that you set the highest value on are actually the most utterly contingent –
Good, good. I understand what you’re saying.
– whereas for the theist it’s the other way round. Presumably, a transcendent mind could have imagined a cosmos that is constituted in a different way, but what it was working towards was one that would develop a life-form that was capable of love, thought and imagination. From that perspective, these things are the least contingent, the most essential, elements in the universe.
To have purpose and meaning imposed on me by a God, however loving and well-meaning, to me feels quite limited compared to it emerging from ourselves. To me, that feels more noble
Does that idea not appeal to you?
If there was some evidence [for it], I would find it enormously appealing. How beautiful that picture would be! But I come from a place where I look out at the world and I use observation and experiment and mathematics – and introspection – to come to an understanding of reality; and that understanding takes me to fundamental physics and the reductionist story.
From my perspective, it is a wondrous and beautiful fact that this hugely contingent (in the language that you’re using) development does yield conscious beings that can experience beauty and wonder and love and illuminate mystery. And that takes me to a place of gratification and reverence for this moment in the cosmological unfolding when these kinds of behaviours can and do take place.
So, it doesn’t in any way diminish for me the value and the wonder of what we humans are capable of. Quite the contrary! It aggrandises it by virtue of seeing it as the tail-end of this long, purposeless, meaningless cosmological unfolding that yields these beings that can then turn back and ascribe purpose and meaning to their lives.
That purpose and meaning being –
Of their own manufacture.
But the very concepts of purpose and meaning are their own invention –
– and may therefore be worthless?
Well, my definition of ‘worth’ is tied to that idea ‘emerging from us’. To have purpose and meaning imposed on me by a God, however loving and well-meaning, to me feels quite limited when compared to it emerging from ourselves. That feels organic. To me, that feels (to use the word you mentioned before) more noble – that it comes from us, it’s of our own making and it’s wondrous and beautiful nevertheless.
But you accept that wonder and beauty are –
Manufactured, artificial. Completely.
My dog seems to find fox shit beautiful.
Yeah. And you can’t argue with that. In his world, it absolutely is.
How does your understanding of the cosmos impinge on your daily life?
I sometimes really do think of myself as just a collection of particles inside a bag called ‘my skin’ that is meandering around the world encountering other bags of particles
Well, at one level it doesn’t, because I go about the world in daily life just like anybody else does. I’ve got to take out the garbage, I’ve got to do the dishes, I’ve got to pick up the kids, right? But at the same time I often find myself being aware of a parallel story, and that can take many forms.
I sometimes really do think of myself as just a collection of particles inside a bag called ‘my skin’ that is meandering around the world encountering other bags of particles, both animate and inanimate. And that perspective – that physical law is moving my particles around and moving other particles around and we’re all just carrying out our quantum-mechanical marching orders – gives me a different insight into the world.
Sometimes I pull back and think about planet Earth in the ‘Pale Blue Dot’ picture,13See solarsystem.nasa.gov. where we’re just this little collection of beings scrambling around on this rock that’s in orbit around this ordinary star in the suburbs of an everyday galaxy. And that gives me a different perspective, a kind of humbling perspective.
Sometimes, I take that a little further and I say: That’s all true – but look at what we’ve been able to understand and accomplish and think about – things that go well beyond the limits of planet Earth, that reach out to the stars and beyond. And that gives me a yet different perspective on things.
My view is [that] you need a collection of these ‘parallel nested stories’. And I do live my life within the collection of those stories in order to have the deepest experience of reality.
Where have you found you struggled most to get these ‘nested stories’ to fit together?
One of the deepest intuitions that we human beings have is that we have free will, and I think that the sharpest notion of free will – that we are the ultimate authors of our actions, our decisions originate within us – is incompatible with our understanding of the physical development of the world. And so I have come to the conclusion that to get the stories to blend in a consistent and coherent manner requires that we don’t trust that intuition of free will. We have to recognise that the sensation of freedom that we experience is a real sensation but does not accurately describe reality.
You are evangelistic (if I can use that word) in propagating an understanding of science. Some people might contemplate what you have just proposed and say: It would destroy society if such an idea caught on.
Suppose I was on trial for murder and I said: ‘I want to call Brian Greene as an expert witness to say I was not responsible, it was all predetermined.’ Would you speak in my defence?
Well, I would be all too willing to articulate my perspective in a general sense – and I would say that the notion that you freely chose (in the intuitive and conventional sense of that term) to carry out your behaviour is incorrect. But at the same time I would say that you are fully responsible for your actions because it was your particles that carried out those actions. You are part of the causal chain of events that led to the death of that individual.
So, at one and the same time I would deny that you have the free will that most people would say that you have and I would also say that you are fully responsible for the consequences of your actions.
Assuming I was guilty, should I be punished for my actions?
So, punishment as retribution doesn’t make sense for me; but punishment in a consequentialist perspective – namely, that punishing a collection of particles for the actions that those particles carried out – can have an influence on other collections of particles, because learning and creativity, even in the absence of free will, are absolutely part of the repertoire of human behaviour and by punishing you for your actions we can dissuade other collections of particles from carrying out similar actions.
And that’s the justification, if you will, for punishment in a world without free will.
Suppose my crime was shoplifting rather than murder but the court still said, from a consequentialist point of view, ‘Shoot him! That will deter others.’ Would you have any comeback to that?
I would definitely have a comeback, because it would certainly be effective in deterring other collections of particles from shoplifting but it’s just too [extreme] a response. The best response for a society is to have a punishment that is commensurate with the crime.
When we interviewed Richard Dawkins in 1995,14See bit.ly/2gQShkX. we said: ‘Suppose some lads kill someone on the grounds that he was old and sick and didn’t contribute anything to society. How would you show them that what they had done was wrong?’
His answer was: ‘I think I would be fairly hard put to it to argue on purely intellectual grounds. I think it would be more: “This is not a society in which I wish to live [and] I’m going to do whatever I can to stop you.”’
When we suggested that they would reply, ‘This is the society we want to live in,’ he said: ‘I think I could finally only say, “Well, in this society you can’t get away with it” and call the police.’
I consider that a fine answer. The only thing I would add is that the laws that we have in a society are a product of the human brain experiencing reality and finding that certain behaviours are acceptable to group living and certain behaviours are not. And we come to that [evaluation] as a group.
There can be other groups in which those individuals’ perspective is the dominant point of view, but in this group (as in most groups around the world) the behaviour of killing the elderly is unacceptable for a number of reasons. We love the elderly. The elderly do contribute. The value of human life is something that we deeply respect and we simply don’t snuff it out because we have a whim to do so.
Most people in this group buy into that perspective, and that’s why it is the controlling perspective. And if you don’t like that perspective, go find another group that agrees with yours – and good riddance to you!
|⇑1||Until the End of Time: Mind, matter, and our search for meaning in an evolving universe (Allen Lane, 2020)|
|⇑2||Notably of Harry Belafonte|
|⇑3||In superstring theory and quantum geometry|
|⇑5||Here Comes the Sun: The spiritual and musical journey of George Harrison (John Wiley & Sons, 2006)|
|⇑6||For example, Francis Collins|
|⇑7||The hypothetical field that drove the initial expansion of the universe in the Big Bang|
|⇑8||The hypothetical field that pervades space and is responsible for the mass of particles|
|⇑9||The hypothetical force that is believed to be causing the universe to continue to expand at an ever-increasing rate. The standard model of cosmology estimates that it makes up about 68% of the mass-energy of the universe.|
|⇑10||Dark matter is composed of particles that do not absorb, reflect or emit light. The standard model estimates that it makes up about 27% of the universe.|
|⇑11||In the 1860s the Scottish physicist James Clerk Maxwell published four equations that describe how charged particles create electric and magnetic fields.|
|⇑12||‘Man is literally split in two: he has an awareness of his own splendid uniqueness in that he sticks out of nature with a towering majesty, and yet he goes back into the ground a few feet in order blindly and dumbly to rot and disappear forever’ (|
Brian Greene was born in 1963 in New York, where he was educated at Stuyvesant High School. He studied physics at Harvard, graduating in 1984, and as a Rhodes Scholar gained his doctorate at Magdalen College, Oxford in 1987.
After a further stint at Harvard, he joined the physics faculty of Cornell University in 1990 and was appointed professor in 1995. Since ’96, he has been a professor of mathematics and physics at Columbia University, where today he is co-director of the Institute for Strings, Cosmology and Astroparticle Physics.
His first book, The Elegant Universe: Superstrings, hidden dimensions, and the quest for the ultimate theory (1999), was an international best-seller. It won a Rhône-Poulenc Prize in 2000 and was a finalist for that year’s Pulitzer Prize for non-fiction. It was later made into a three-hour PBS television special which won a 2003 Peabody Award.
It was followed by The Fabric of the Cosmos: Space, time, and the texture of reality (2004), which was made into a four-hour PBS television special; The Hidden Reality: Parallel universes and the deep laws of the cosmos (2011); and Until the End of Time: Mind, matter, and our search for meaning in an evolving universe (2020). His book for children, Icarus at the Edge of Time, was published in 2008.
In 2008, with his wife, the US television producer Tracy Day, he founded the annual World Science Festival in New York.
He has lectured in more than 25 countries. He has frequently appeared on US television, and contributes occasionally to the New York Times.
He received the Andrew Gemant Award from the American Institute of Physics in 2003, the Bertrand Russell Society Award in 2011 and the Richtmyer Memorial Award from the American Association of Physics Teachers in 2012.
He has a son and a daughter.
Up-to-date as at 1 April 2020