Georges Braque, the French Cubist painter, wrote that, “Art is meant to disturb, science reassures.” Bertrand Russell, one the great philosophers of the 20th century, disagreed. In his book, The Impact of Science on Society (1952), Russell argued that science is disruptive. Science dispels unfounded traditional beliefs. It can also be put to myriad social uses: changes to the organisation of society, political transformations, and, of course, war. Science enabled the “victory of humanity and common sense”. Scientific medicine banished superstition, sorcery, and witchcraft. Observation overcame authority. The physical world was proven to be autonomous. And Aristotle was wrong: there was no such thing as a final cause, a mysterious purpose to all things. Russell wrote that science has enabled us to know and to do. And it was this power that posed its greatest threat: “if unchecked, [science] may inspire a form of unwisdom from which disastrous consequences may result”. Science confers great power on a small technical elite. That elite risks becoming an oligarchy, totalitarian, monolithic, and utterly self-interested. Democracy can counter technocracy. But Russell worried that democracy was eroding, leaving the power of technical elites unchallenged. He was writing at the dawn of the atomic age. He was anxious that human beings were becoming cogs in a society they were increasingly unable to control, let alone understand. “A democratic scientific society”, he wrote, “by exacting service and conferring security, forbids or prevents much personal initiative which is possible in a less-regulated world”. Russell warned that science risked destroying the delicate natural systems that sustain life on our planet. His conclusion was utopian: “a single government of the whole world, possessing a monopoly of armed force and therefore able to enforce peace” was the only possible solution. Reading Russell today is a resonant experience. Existential fears surround us. Yet today seems a long way from the dream of Enlightenment. Modern science is a brutally competitive affair. It is driven by incentives to acquire money (research funding), priority (journal publication), and glory (prizes and honours). Science's metrics of success embed these motivations deep in transnational scientific cultures. At The Lancet, while we resist the idea that Impact Factors measure our achievements, we are not naive enough to believe that authors do not judge us by those same numbers. It is hard not to capitulate to a narrow range of indicators that has come to define success and failure. Science, once a powerful force to overturn orthodoxy, has created its own orthodoxies that diminish the possibility of creative thought and experiment. At this moment of planetary jeopardy, perhaps it is time to rethink and restate the purpose of science. Science has three conventional roles. First, to embody the quest for truth—a property that all societies have revered. Second, to accumulate reliable and valid knowledge. And third, to marvel at the wonder of our natural and physical worlds. These functions of science are not controversial. They are high-minded. And they present little threat to the order of society. Truth, knowledge, and wonder are the foundations for science's contract with society. But they are insufficient. The collective predicaments we face demand a much more dynamic notion of science in society. Science creates a platform of scholarship for intervening in society. Scientists are trusted voices in the public sphere. They have a responsibility to find their voice and speak out. Science, through independent measurement, provides a robust means for holding those in power accountable for their publicly stated promises and commitments. Science contributes importantly, through its constant claim for freedom of inquiry, to the total quantity of liberty in society. And science is an important basis for social cohesion and peace by achieving a common and agreed view of our world and its problems. One does not have to conclude, as Russell did, that a safe future for our species requires a single global government. A more modest (and feasible) conclusion might be that science provides the means—if we can escape the damaging incentives that modern scientific cultures nurture—to use knowledge to tame the extraordinary and inscrutable power of governments, corporations, and institutions. We have never needed science more than we need it today. But truth, knowledge, and wonder alone are not enough.