Stephen Hawking collaborator talks about the moment the famed physicist said it was ‘time to stop playing God’ | CBC Radio

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After finishing his PhD, Thomas Hertog — a close collaborator of Stephen Hawking’s — set out on a vacation travelling the Silk Roads. 

Hertog was stuck on a bridge in northern Afghanistan when he received an email from Hawking, asking him to ditch his vacation and come back to work with him.

“This was the moment that he realized that A Brief History of Time was written from the wrong perspective,” Hertog said. 

Hertog did as he was asked. The border guard there in Afghanistan turned out to be a fan of Hawking’s, and let Hertog pass after seeing the physicist’s email.

Hawking’s book, A Brief History of Time, reshaped science’s understanding of the universe by positioning the Big Bang as the beginning of time itself. This realization that he had been wrong about the origin story set both Hawking and Hertog to work on a new model for the universe.

In his book On the Origin of Time: Stephen Hawking’s Final Theory, Hertog explains how he and Hawking’s thinking changed. A theoretical physicist and professor at University of London, Hertog  spoke with The Current host Matt Galloway about Hawking’s amazing ways of thinking and their work together. Here is part of their conversation.

You say that there was a touch of magic about Hawking. What do you mean by that?

When I met him, [it] was 1998. A Brief History of Time had already been published. He was already famous, but he could not write any equations anymore. By then, he had developed this amazing ability to do research in theoretical physics … almost in his head. He had devised this visual way of manipulating shapes and forms and universes and black holes so that he could, sort of, develop his intuition without having to do these actual calculations. 

And this drove many of us mad, right, because we were doing these calculations and he was figuring it out in his head. [But] I loved it from the very first second that I met him in ’98. I just loved it.

You describe the practical elements of [working with Hawking] when communication got increasingly difficult for him, but when you were able to get past that, it must have been exhilarating to work with him.

We worked together for 20 years. We came to great new insights when he was using his computer voice in the late ’90s and early 2000s. Communication was, all in all, fairly fluent. 

But that communication slowed dramatically six, seven years before he died. But … by that time, it turned out we had developed some sort of common language, and we began to collaborate using a lot of non-verbal communication. 

And so by the end of his life, I could sort of fire questions at him [and] detect through his facial expressions several degrees of no and several degrees of yes. And so this became a very strong bond because in a way; it’s almost like we developed a sort of intimacy around cosmology. 

A Brief History of Time is kind of mind bending in what it explains. Explain what the essence of that theory of the universe was.

In the early ’80s, Stephen put forward a scientific model that he interpreted as the creation of our universe — the creation of space, time and matter out of what he called nothing. And of course, everyone asks, well, what does it mean, nothing? What came before the Big Bang?

But this was a monumental achievement in its own right, because until then, the Big Bang, the actual beginning of time, was thought to be … not solvable within science. And there comes Hawking with a scientific model that includes the Big Bang. 

But unfortunately, his model created an empty universe — a universe without stars and galaxies and life, and therefore not a very useful universe. And so that’s what got him thinking about a much better theory, which ultimately led to a completely different view.

What was your reaction when he said that he had changed his mind?

I had sort of expected it, because such fundamental changes in our thinking about the universe, it’s this typical story of paradigm shifts in science. The model that you’re working with doesn’t work, and at some point, one of the key assumptions must just go.

We were getting into such a paradigm crisis, and then we were apart. And it sort of crystallized in my mind — and apparently it very much crystallized in his mind — that [the] assumption of A Brief History of Time had to go.

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One of the things he says to you is, “It’s time to stop playing God.” What was it that changed for him?

We have built physics over many, many generations and centuries from what Stephen calls a God’s-eye perspective. This is really the success of science — that we have been able to study the world in a sort of objective manner, as if we are outside the system that we are trying to understand.

If you’re trying to understand the habitability of our universe, the fact that we exist in the universe, it is obviously wrong to try to look at it from the outside. And that’s what Stephen did in A Brief History of Time, and that’s why he told me [it’s] written from the wrong perspective.

It takes an incredible amount of humility for someone like Stephen Hawking to say that he had the perspective wrong, doesn’t it?

Yes, I am sure. I admire him for that. Stephen had an ego, of course, but his passion for understanding was greater.

What are the implications of [this new theory], do you think?

There are many. We’re always told the laws of physics as some sort of eternal truth. We arrive at a fundamentally evolutionary understanding of those laws. So no real foundation, much like the laws of biology in a way, which emerged together with various layers of life. So that’s the grand implications.

What does it say about the role of a higher power in helping to explain how it is that we are here?

We’ve always thought of the laws of physics as immutable, eternal truths. And now I’m saying they’re the result of an evolution, which involved a lot of channels and some necessity and a random process. This model allows you to reveal the interconnectedness, not just between the different species of life, but between the physical levels of the universe.

We are also saying, precisely because we put that evolutionary character so central, that maybe the idea that we would find an absolute answer for a final theory in physics was misguided. Maybe there are limits to science. Maybe there is a certain finitude associated with that. And that, of course, leaves room for some mystery.

You end the book by saying that Hawking was the freest man that you have known. What did you mean by that?

He was intellectually free. He was so ready to ditch dogmas and to reimagine the world and to rethink the foundations of physics. I never met anyone like him. This feeling of freedom, despite these terribly difficult conditions … it was very special.

Q&A edited for length and clarity.