If you want to do good in the world, should you be a doctor, or an aid worker? Or should you make a billion or two any way you can, and give it to good causes? Billionaire Sam Bankman-Fried argues this is the best use of his vast wealth. But philosophers argue charitable giving is often driven not by logic, but by a sense of personal attachment. David Edmonds traces the latest developments in the effective altruism movement, examining the questions they pose, and looking at the successes and limitations.