Stephen Hawking's Brief Answers to the Big Questions, review: A beautiful little book by a brilliant mind

Stephen Hawking
A lovely line in self-deprecation: Stephen Hawking Credit: Getty

If you look up at the sky at night, you will notice that it is mainly dark. This seems too obvious to mention, but it became a crucial piece of evidence for scientists in the mid-20th century who were worried about the greatest existential questions. If the universe is eternal and infinite, then the night sky should be a homogeneous blaze of light, from all the countless stars lying in every direction. The fact that it isn’t is one key part of the proof that the universe must have had a beginning at some finite point long ago.

The physicist Stephen Hawking was one of the brilliant minds working on such cosmological puzzles, and made his name working on black holes. (He discovered what is now called the “Hawking radiation” that they emit.) At the time of his death, he was working on this collection of short scientific and philosophical essays, which has been completed by his colleagues and family. It is a fitting last message from a genius and spiky wit, who was at least more intellectually qualified for the role of cosmic guru than others — Yuval Noah Harari, say, or Jordan Peterson — jostling to claim that role today. 

Hawking had a mischievous humour and a lovely line in self-deprecation. As he relates in an early autobiographical segment here, his undergraduate results at Oxford were on the borderline between a first- and second-class degree, so he was called in for a chat. “In the interview they asked me about my future plans. I replied that I wanted to do research. If they gave me a first, I would go to Cambridge. If I only got a second, I would stay in Oxford. They gave me a first.” He later observes that, if we had a mini black hole that weighed about the same as a mountain, we could keep it in orbit around Earth and use it for free power for the whole planet. “People have searched for mini black holes of this mass, but have so far not found any,” he relates. “This is a pity because, if they had, I would have got a Nobel Prize.”

A fitting last twinkle from a new star: the cover of Stephen Hawking's final book  Credit: AFP/Getty

Not the least of the problems exercising that remarkable brain in his last months, it seems, was Britain’s imminent departure from the EU, to which Hawking often makes sarcastic mention. If he had studied with the physicist Fred Hoyle, he says, he would have found himself having to defend Hoyle’s “steady-state” theory of the universe, which was overturned by the new theory of the Big Bang: doing that, Hawking says, “would have been harder than negotiating Brexit”. 

The issue of Brexit, of course, is not in itself a scientific one, as much harm as it threatens to cross-border scientific collaborations. In a fondly awestruck preface, the physicist Kip Thorne points out that the “big questions” in this book fall into two types: the strictly scientific questions, and the more political or metaphysical ones. But the lines between the two can be fuzzy. One of the questions Hawking addresses, for instance, is the existence of God, which blends imperceptibly with the question of why we are all here. (I don’t mean why we are all here on this rain-sodden island, but how the universe came to exist.) “I don’t have a grudge against God,” Hawking says, tartly putting the reader in mind of other high-profile scientists who do. But Hawking has no need of the God hypothesis. Perhaps, some suggest, God created the initial conditions and laws of the universe and then sat back to watch it run. Hawking objects that time itself began with the Big Bang, so beforehand “there is no time for God to make the universe in”. 

Instead, he declares, “I think the universe was spontaneously created out of nothing, according to the laws of science.” A pedant might here note that the word “spontaneously” itself implies the existence of time in which something can suddenly happen, but if there is no time for God to make the universe, there is no time in which the Big Bang can “spontaneously” take place either. But never mind: here is some physics about how all the positive and negative energy and universe add up neatly to zero. This means, Hawking concludes impressively, that “if the universe adds up to nothing, then you don’t need a God to create it. The universe is the ultimate free lunch”. It appears that this might be the one case where you really can have your cake and eat it.

Hawking’s gift for vivid scientific storytelling is beautifully employed throughout: there is a terrific explanation of why exactly we live in three big dimensions of space, rather than two, four, or more, as well as exactly how time travel is allowed by the equations of relativity, and whether we could ever find out what is inside a black hole. Peering into the future, on the other hand, Hawking becomes necessarily political. He notes the looming threats such as global warming, nuclear war, and the mathematical certainty of another large asteroid strike, of the kind that killed off the dinosaurs. Gloomily, he says it is “almost inevitable” that one of these will render our planet uninhabitable within the next millennium. This is why, he insists, we need to get out into space and colonise other planets. We also need to develop cheap nuclear-fusion power, and tread cautiously with AI. “We spend a great deal of time studying history, which, let’s face it, is mostly the history of stupidity,” he notes unimpeachably. “So it’s a welcome change that people are studying instead the future of intelligence.”

Unfortunately the universe itself will eventually end. One way that might happen is a Big Crunch: the expansion of the universe goes into reverse and everything collapses back to a single point. When he was travelling in the Far East, Hawking  was warned not to mention the Big Crunch for fear of the effect it might have on the markets. But we, he reports happily, are more phlegmatic. “In Britain, people don’t seem too worried about a possible end twenty billion years in the future. You can do quite a lot of eating, drinking and being merry before that.” 

Despite everything, then, Stephen Hawking was proud to be British — but he also belongs to the far grander story of the universe waking up and beginning to understand itself. This beautiful little book is a fitting last twinkle from a new star in the firmament above.