Following the sad news of the death of Stephen Hawking, New Atlas takes a moment to look not only at some of his most memorable, inspiring and challenging quotations, but to set them in the context of his life and work. Brace yourself for a whirlwind tour of free will, the state of humanity, God and fake news, all thanks to one of science's finest minds – except for the quote that probably wasn't him…
"I have noticed even people who claim everything is predestined and that we can do nothing to change it look before they cross the road."
The question of free will has long been a mainstay of philosophy and science, and it's a topic Hawking visited from a scientific point of view in his essay Is Everything Determined from his book Black Holes and Baby Universes and Other Essays, first published in 1993. It's the origin of this quotation. The next line is less-frequently cited, however: "Maybe it's just that those who don't look don't survive to tell the tale."
Hawking touches on a grand unified theory of science, quantum mechanics, natural selection, DNA, the complexity of the human brain and fluid dynamics in particular before arguing that assuming that we have free will is the safest course of action.
But that's not the whole story. Hawking eventually concludes: "Is everything determined? The answer is yes, it is. But it might as well not be, because we can never know what is determined."
"We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special."
Hawking's views on his species are hard to pin down, and for every inspiring quote such as this one, which appeared in Der Spiegel on October 17, 1988, there's another more grounding assessment.
Take this quote from a speech given at 1994's Macworld Expo in Boston: "I think computer viruses should count as life … I think it says something about human nature that the only form of life we have created so far is purely destructive. We've created life in our own image."
These views aren't mutually exclusive. Though Hawking thought it most unlikely that we're alone in the universe, he also thought that humans were probably the only intelligent life for hundreds of light years, and hence special. But he was also a critic of the direction mankind was taking, as we'll see…
"We are in danger of destroying ourselves by our greed and stupidity. We cannot remain looking inwards at ourselves on a small and increasingly polluted and overcrowded planet."
This, from an interview with CNN on September 10, 2010, was typical of Hawking's views on the environment. In January of 2007 he and astronomer Sir Martin Rees met to formally move the hands of Doomsday Clock of the Bulletin of the Atomic Scientists to five minutes to midnight. The clock symbolizes humanity's proximity to a self-made global catastrophe, historically nuclear war. But the change of 2007 was the first made in light of climate change.
In 2006, Hawking got 25,000 responses when he posed this question on Yahoo Answers: "In a world that is in chaos politically, socially and environmentally, how can the human race sustain another 100 years?" He later said he posed the question because he didn't have the answer himself.
"Life on Earth is at the ever-increasing risk of being wiped out by a disaster, such as sudden global nuclear war, a genetically engineered virus or other dangers we have not yet thought of."
Hawking said this at a Hong Kong press conference on June 13, 2006, but it followed a rather more upbeat exhortation: "It is important for the human race to spread out into space for the survival of the species." And he was fairly upbeat about the odds. "I think we have a good chance of surviving long enough to colonize the solar system," he told Time in 2010, in response to a reader question.
On the other hand, he also emphasized the need to go further, and the difficulty in doing so. "We won't find anywhere as nice as Earth unless we go to another star system," he said in Hong Kong. "It is not clear if we would survive if the Earth was made unfit for habitation," he later told Time.
"So Einstein was wrong when he said, 'God does not play dice.' Consideration of black holes suggests, not only that God does play dice, but that he sometimes confuses us by throwing them where they can't be seen."
Like Einstein before him, it's likely that Hawking's use of the word God was metaphorical rather than literal, and indeed, this Hawking quote originates from a very technical 1994 paper, titled The Nature of Space and Time, where he sought to make a point about uncertainty in Quantum Theory.
In a Guardian interview on May 15, 2011, Hawking spoke more straightforwardly about his position on God in the afterlife. "I regard the brain as a computer which will stop working when its components fail," he said. "There is no heaven or afterlife for broken down computers; that is a fairy story for people afraid of the dark."
"What I have done is to show that it is possible for the way the universe began to be determined by the laws of science," he told Der Spiegel, (October 17, 1988 again). He said "In that case, it would not be necessary to appeal to God to decide how the universe began. This doesn't prove that there is no God, only that God is not necessary."
"Science predicts that many different kinds of universe will be spontaneously created out of nothing. It is a matter of chance which we are in."
This quote, also from The Guardian's May 15, 2011 interview, touches on M-Theory, a theory of mathematics and physics that attempts to unify string theory, and which is a potential precursor to a unified theory of science. It necessitates a universe of 11 dimensions, including time.
"We should seek the greatest value of our action," Hawking responded when asked what we should do with our time in a random and spontaneous universe.
"My expectations were reduced to zero when I was 21. Everything since then has been a bonus."
This quote was given to the New York Times of December 12, 2004. Following his diagnosis with a rare form of motor neurone disease, doctors gave Hawking only a few years to live. But it steadily became apparent that, unlike other forms of the disease, the severe prognosis proved increasingly inaccurate. He refused to let it be an obstacle to his work. "In my opinion, one should concentrate on activities in which one's physical disability will not present a serious handicap," he wrote in 1984.
He also had a keen sense of humor, apparently telling an Israeli television station in 2007: "The downside of my celebrity is that I cannot go anywhere in the world without being recognized. It is not enough for me to wear dark sunglasses and a wig. The wheelchair gives me away."
"The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."
This quote, though often attributed to Hawking, was probably never said by him, but instead by Daniel J. Boorstin in The Washington Post in 1984 while Librarian of the United States Congress.
Still — not a bad quote, and one with a whiff of irony about it, assuming, as it seems, Hawking never said it, given in its inclusion in various outlets today. Perhaps he would have enjoyed that. Rest in peace, Professor.