Correspondence www.thelancet.com Vol 395 January 11, 2020 113 leadership and multistakeholder dialogue through whole-of-govern- ment and society strategies. Governments need the capacity to enact and enforce laws, abiding by the rule of law. Yet, fundamental challenges exist to finding legal solutions that effectively authorise and finance health coverage that serves all inhabitants. Governments face competing social priorities, budget constraints, corruption, industry influence, and conflicts of interest. If universal health coverage is to become a reality, governments must ensure health for all by addressing underlying health determinants, including social, economic, com mercial, and environmental factors. To support universal health coverage goals, governments must promote and protect human rights such as non-discrimination and inclusive participation. Reaching the most vulnerable and marginalised popu- lations requires specific investments, including dismantling human rights barriers to service access. The trade-offs inherent in realising universal health coverage include universal access (who is covered), cost (pooled funds), and services covered. Moving towards universal health coverage requires law extending coverage to more people; offering more services to meet essential health needs; and protecting people from poverty due to out-of-pocket expenditures. Regulatory oversight should ensure high-quality primary, secondary, and tertiary services, including palliative and emergency care. Supporting countries to develop legal frameworks aligned with universal health coverage requires substantial resources and political resolve. The Legal Solutions Network will help scale up essential legislative capacities, share good practice, and raise awareness. The first step will be for UN agencies, the Inter- Parliamentary Union, non-government organisations, academic institutions, and other partners to create a new network focused on law as a key determinant of universal health coverage, as advocated by the Lancet Commission. LOG and JTM were co-chairs of the Lancet–O’Neill Institute Commission. All other authors declare no competing interests. *Lawrence O Gostin, Aleksandra Blagojevic, Simon Bland, Mandeep Dhaliwal, Ranieri Guerra, John T Monahan gostin@law.georgetown.edu O’Neill Institute for National and Global Health Law (LOG) and Georgetown University Global Health Initiative (JTM), Georgetown University, Washington, DC 20001, USA; Inter-Parliamentary Union, Geneva, Switzerland (AB); UNAIDS, Geneva, Switzerland (SB); UN Development Programme, New York, NY, USA (MD); and WHO, Geneva, Switzerland (RG) 1 United Nations. Political declaration of the high-level meeting on universal health coverage: “universal health coverage: moving together to build a healthier world”. Sept 23, 2019. https://www.un.org/pga/73/ wp-content/uploads/sites/53/2019/05/UHC- Political-Declaration-zero-draft.pdf (accessed Sept 24, 2019). 2 Gostin LO, Monahan JT, Kaldor J, et al. The legal determinants of health: harnessing the power of law for global health and sustainable development. Lancet 2019; 393: 1857–910. approach—the very segregationist thinking described in Snow’s lecture—becomes terribly ill-suited; it confines inquiry to a given set of facts, methods, and heuristics when our problems demand an integrative, multidisciplinary comprehension. 2 One particular group of people have been masters in the latter approach; they have navigated seamlessly across different oceans of knowledge and, for them, the two cultures never existed: the polymaths. These bold, cross-disciplinary, inquirers espouse perfectly the kind of broad, profound, and integrative thinking that has become crucial today. Polymathic thinking is at the heart of both innovation and critical thinking. They all involve the effort to examine, enlarge, and enrich our knowledge by transcending extant boundaries or limitations. Polymathic breadth, rather than detrimental to rigorous inquiry, provides the resources necessary for critical thinking and sheds light on previously unseen gaps in our understanding. 3 It helps us identify common foundations among disciplines, offering solid grounds for future inquiry. 4 It fosters development of rich collections of ideas, experiences, and skills that enable novel and surprising combinations, which can lead to powerful, otherwise unreachable, insights. 5 Unsurprisingly, humanity’s most celebrated discoveries came from people who engaged with a variety of interests and integrated them into synergistic networks of enterprise. 6 Clearly, whenever critical thinking or innovation are necessary, it pays to encourage the development of the rich, examined, and integrated repertoire that is the hallmark of polymathy. We have been in the age of the two cultures for too long—the losses, as Snow foreshadowed 60 years ago, are taking their toll. To face today’s daunting problems, our institutions must go beyond their old, Scientific polymathy: the end of a two- cultures era? In 1959, the chemist and novelist Charles Percy Snow delivered his famous lecture with a warning about the emerging “gulf of incomprehension” between the humanities and the sciences. 1 This divide between these two cultures, Snow predicted, would jeopardise our ability to inquire broadly and ultimately hamper our capacity to solve important complex problems. Today, we face numerous problems, from global health challenges to environmental crises, whose range and scope go far beyond any single discipline. Consequently, our standard Central Press/Stringer/Getty Images