Peter Singer starts with this initial piece at the Boston Review:
I met Matt Wage in 2009 when he took my Practical Ethics class at Princeton University. In the readings relating to global poverty and what we ought to be doing about it, he found an estimate of how much it costs to save the life of one of the millions of children who die each year from diseases that we can prevent or cure. This led him to calculate how many lives he could save, over his lifetime, assuming he earned an average income and donated 10 percent of it to a highly effective organization, such as one providing families with bed nets to prevent malaria, a major killer of children. He discovered that he could, with that level of donation, save about one hundred lives. He thought to himself, “Suppose you see a burning building, and you run through the flames and kick a door open, and let one hundred people out. That would be the greatest moment in your life. And I could do as much good as that!”
Two years later Wage graduated, receiving the Philosophy Department’s prize for the best senior thesis of the year. He was accepted by the University of Oxford for postgraduate study. Many students who major in philosophy dream of an opportunity like that—I know I did—but by then Wage had done a lot of thinking about what career would do the most good. Over many discussions with others, he came to a very different choice: he took a job on Wall Street, working for an arbitrage trading firm. On a higher income, he would be able to give much more, both as a percentage and in dollars, than 10 percent of a professor’s income. One year after graduating, Wage was donating a six-figure sum—roughly half his annual earnings—to highly effective charities. He was on the way to saving a hundred lives, not over his entire career but within the first year or two of his working life and every year thereafter.
Wage is part of an exciting new movement: effective altruism. At universities from Oxford to Harvard and the University of Washington, from Bayreuth in Germany to Brisbane in Australia, effective altruism organizations are forming. Effective altruists are engaging in lively discussions on social media and websites, and their ideas are being examined in the New York Times, the Washington Post, and even the Wall Street Journal. Philosophy, and more specifically practical ethics, has played an important role in effective altruism’s development, and effective altruism shows that philosophy is returning to its Socratic role of challenging our ideas about what it is to live an ethical life. In doing so, philosophy has demonstrated its ability to transform, sometimes quite dramatically, the lives of those who study it. Moreover, it is a transformation that, I believe, should be welcomed because it makes the world a better place.