High-profile scientific bets date at least to the late 19th century. They've become more common in recent years as researchers leverage better communication technologies to raise awareness of basic scientific questions and disputes.
Hawking, more than most of his peers, seemed to appreciate the possibilities. In 1974, he bet CalTech physicist Kip Thorne that Cygnus X-1, a bright object in the constellation Cygnus, wasn't a black hole. In 1990, he announced that the accumulated evidence meant he'd lost the bet (which he paid off with a subscription to Penthouse). The subsequent publicity raised the profile of black holes, and Hawking, for years.
Hawking continued wagering. In 1997, he and Thorne bet another CalTech physicist, John Preskill, that information swallowed by a black hole could never be retrieved. If Hawking and Thorne were right, the finding would undermine the basic tenets of physics. Hawking worked on the problem until 2004, when he used the occasion of a major physics conference to announce he'd devised a calculation that proved he was wrong. As the losing party, he presented to Preskill a baseball encyclopedia from which information could easily be retrieved. The bet was covered globally, as was the scientific question at the heart of it — and Hawking's embrace of his own error.
Hawking's bets were generally made with friends and colleagues unlikely to feel the sting of losing to the celebrity scientist.
When Hawking bet against the Higgs boson, he wagered with Gordon Kane at the University of Michigan, not Higgs himself. The intention was good-natured: Hawking believed that a failure to discover the predicted particle would be more interesting for physics.
Higgs didn't take kindly to the suggestion and, rather than engage Hawking, continued to call into question his scholarship. Ever the gentleman, Hawking didn't take the bait. After the Higgs boson was confirmed in 2012, Hawking made a global spectacle of paying off the US$100 wager, admitting he was wrong and calling for Higgs — his longtime critic — to be given the Nobel.
Hawking's humility and graciousness would be rare in any age, but particularly at a time when conceding even the slightest error is viewed as a weakness to be derided and exploited. As key scientific fields like climate change and vaccinations become politicised, this kind of rigidity also infects how we do and don't discuss them. Public-facing scientists become reluctant to concede uncertainty about data for fear that the admission will undermine funding and support for their research. The result: well-intentioned intellectuals who feel obligated to present science as a series of truths not to be argued or doubted.
If Hawking's life can teach anything to scientists, public intellectuals and social media users, it's that humility and a willingness to change one's mind are a sign of not weakness but an adventurous and intellectually engaged mind and polity. That's a legacy as worthy as Hawking's monumental scientific achievements.