Effective altruism is a philosophy and social movement that advocates the use of evidence and reasoning to determine the most effective ways to benefit others. Altruism refers to improving the lives of others—as opposed to egoism, which emphasizes only self-interest. Effectiveness refers to doing the most good with whatever resources are available—as opposed to only doing some amount of good—as well as determining what is the most good by using evidence and reasoning—as opposed to only doing what feels good or appears intuitively appealing.