How many philosophers does it take to change a light bulb? It depends on how you define change. Philosophy is often viewed as irrelevant, and philosophers as living in ivory towers, easily dismissed for quibbling over words and arguing for the sake of argument. Senator Marco Rubio, during a fleeting bid for the Republican nomination, challenged philosophy's value when he proclaimed that America needed "more welders and less philosophers." Not so fast, Rubio. Some philosophers are changing the world.

Today innovative work in philosophy combines philosophical analysis and rigor, with organizational acumen and leadership. Much of this innovation is taking place in applied ethics. Typically, applied ethics involves identifying and analyzing social problems; sometimes it also proposes means for solving those problems in an ideal world. It rarely creates mechanisms capable of solving problems in the real world.

However, pioneering philosophers have used philosophy to operationalize moral goods by creating tools that tackle social problems in the real world. Lisa Fuller, Thomas Pogge, Peter Singer, and Leif Wenar lead the charge, employing philosophy as an instrument to advocate for the world's most vulnerable people. Working with organizations such as Médecins Sans Frontières (MSF), collaborating with practitioners of various kinds, designing strategy, and founding and managing organizations that implement philosophical insights are among the tools high-impact philosophers use. The world is a better place because of their efforts.

Lisa Fuller collaborated with MSF to give voice to the moral principles that guide humanitarian action. In her report, "Many Missions, One Voice: Justice and Integrity in MSF Operational Choices," Fuller identifies the moral principles that underlie MSF's actions and policies. The report was based on field research she conducted at a Somalian mission, as well as at other global sites. She observed the MSF team in the field and at their meetings, and she reviewed their documents and reports. Since MSF saves lives in some of the poorest and most devastated countries, and does so with limited resources, it is critical that the organization act on the basis of sound moral principles. Fuller found that MSF's actions are guided by the values of organizational independence, impartiality with respect to people served, proximity, neutrality, solidarity, integrity, collectivism, and justice. Making these principles transparent facilitates systematic and coherent humanitarian action by MSF. It also raises the moral bar for other non- governmental organizations. Fuller's work demonstrates that philosophy can improve the decisions of organizations, and the lives of those they serve.

The Health Impact Fund (HIF), Thomas Pogge's undertaking, addresses the failure of the international patent system to provide medicines to the poorest and sickest populations in the world. Pogge designed a system that incentivizes research on neglected diseases by rewarding research and development that significantly reduces the global burden of disease. Qualifying pharmaceutical firms compete for health impact rewards on the basis of their measurable impact on global health. Those with demonstrated impact win health impact dollars, providing the funding needed to conduct research and development on neglected diseases. The HIF is currently piloting bedaquiline, a drug to treat multi-drug resistant TB, in Mumbai, India. The HIF strategically marries rewards for pharmaceutical companies with health benefits for the global poor. It is an innovative approach to solving an intractable problem: it effectively incentivizes buy-in from a notoriously reluctant industry.

In 2009, Peter Singer founded The Life You Can Save, an organization designed to increase giving and to improve giving practices. It is now a tax-deductible charity. The Life You Can Save advocates for effective giving by encouraging people to give more money to charity and to give it where it will have the greatest impact. The organization recommends specific charities based on extensive and rigorous research. It also gives donors a forum in which to pledge to donate a certain amount of money to charity. The public nature of the pledge encourages others to give as well. Today, savvy donors can read Singer's philosophical arguments on charity and can turn to The Life You Can Save to guide them in their giving choices. Singer's philosophical work, and the organization that he built to operationalize it, has done nothing less than spawn a new giving movement: effective altruism.

Leif Wenar, in his recent book, Blood Oil, sheds light on the devastation to resource-cursed countries that results from purchasing oil from these countries. He argues persuasively that the purchasing practices of affluent countries, guided by the rule of might makes right, only cause human misery for the people living in those countries. Particularly compelling is his two-pronged proposal for a remedy. The Clean Trade Act would protect the property rights of resource-cursed countries by making it illegal to purchase oil from those countries. The Clean Hands Trust would consist in trusts, funded through taxes imposed on countries that purchase oil from disqualified countries in violation of the Clean Hands Act. Eventually, the money from these trusts would be returned to the citizens in resource-cursed countries, who have had their oil stolen from them. Together, the Clean Trade Act and the Clean Hands Trust promise justice for resource-cursed countries and provide the leverage needed for buy-in.

High-impact philosophy reflects an innovative spirit. Given a desire to make the world a better place for all people, it bridges the gap between analysis and practice and finds ways to operationalize philosophical wisdom. Identifying moral problems, and building and managing organizations to work toward solving them, bespeaks a unique and welcome skill set within philosophy. Cogency, clarity, and analysis are good and well, but if the insights they reveal cannot be implemented in the messy world in which we live, their relevance is at best limited. High-impact philosophy merges philosophy, the love of wisdom, with philanthropy, the love of mankind, in the service of a better world for all people. It moves philosophy beyond analyzing and explaining injustice to advocating for the victims of injustice. It is a welcome addition to the toolkit for global justice.