Brief Answers to the Big Questions by Stephen Hawking review – God, space, AI, Brexit

The late Stephen Hawking did not believe in an afterlife, but he has one all the same. He has appeared as a co-author in two posthumous research papers since he died in March. One takes a fresh look at the problem of just how complex the universe far beyond our horizon could be; the other returns to the intractable but apparently not entirely insoluble problem of what happens to information once it falls into a black hole. This second paper is a response to a paradox that concerns only theoretical physicists but the first addresses the machinery of creation that seems to have needed no creator.

Not surprisingly, he returns to both themes and many more in what his publishers call his final thoughts. Pioneering thinkers leave their names on their science. Hawking and Roger Penrose proved mathematically in 1965 that time, space and matter must have had a beginning in an infinitely small, dense point. Radioastronomers separately identified tantalising evidence of creation inscribed in the cosmos that year. Hawking also pursued another unknowable object to establish the theoretical reality of an elusive entity, instantly dubbed Hawking radiation, from within the forbidden frontiers of a black hole.

There is no way of physically demonstrating the reality of either universal self-manufacture or Hawking radiation, but his scientific peers embrace his reasoning. His latest book is, however, a market test of what is known within the publishing world as the Hawking effect. A Brief History of Time joined the bestseller lists as soon as it appeared in 1988 and stayed there into the next decade. It sold more than 20m copies in 40 languages and turned an astronomer into a star, famous enough to twinkle in guest appearances in Star Trek and The Simpsons. It helped revive an appetite for popular science books, especially those with space for time, wonder, alien intelligence, superhumans and God.

Brief Answers is one of his last projects, completed for him after he died. It draws on half a million or so words stored over the decades in the form of essays, lectures, keynote speeches and – since A Brief History of Time made him a celebrity and his long struggle against illness made him an icon – it addresses some of the questions that, over the decades, so many people had often asked him.

Those who followed Hawking the writer after 1988 will find much that seems familiar. For those readers who invested in A Brief History and perhaps never quite finished it, there is good news: almost everything in Brief Answers is effortlessly instructive, absorbing, up to the minute and – where it matters – witty. There is a graceful foreword by Eddie Redmayne, who played Hawking in The Theory of Everything, the 2014 film of his life; there is a thoughtful introduction by his colleague and friend Kip Thorne, the Californian scientist behind the identification, in 2016, of gravitational waves generated by the collision of two black holes; there is a touching afterword by his daughter Lucy Hawking. In between, there are personal responses to the God question, the colonisation of space question, the artificial intelligence question, the survival of the planet question, and even his Desert Island Discs.

The observable universe fashioned itself without a cause, and has a net energy of zero. “If the universe adds up to nothing, then you don’t need a God to create it. The universe is the ultimate free lunch,” he writes.

It would be, he says “our worst mistake ever” to dismiss the notion of highly intelligent machines as mere science fiction. “Our future is a race between the growing power of our technology and the wisdom with which we use it. Let’s make sure that wisdom wins.” He warns that human aggression and new technologies – nuclear warheads, AI, genetic engineering, global warming – could destroy the entire human race and much of the rest of life on Earth. And he wants more manned space exploration. “If humanity is to continue for another million years, our future lies in going boldly where no one else has gone before.”

People who argue for good education for all, a decently funded NHS and serious investment in research will rediscover him as a friend. He doesn’t think much of the anti-immigration ideologies of Brexit or Trump, but says so with brevity.

And he concedes that despite all the amazing advances of cosmological physics in his lifetime, the final theory that defines why the universe is as it is, the theory of everything, seems as far away as it did in 1988. That doesn’t bother him. In the next 50 years, he says, “we will find out what happened at the big bang. We will come to understand how life began on earth. We may even discover whether life exists elsewhere in the universe.”

As he says more than once, he prefers optimism to pessimism. “At one point I thought I would see the end of physics as we know it, but now I think the wonder of discovery will continue long after I am gone.”