Effective altruism asks: which problems are most important to solve — and how do you compare them?

Peter Singer's 1971 essay 'Famine, Affluence and Morality' argued that if we can prevent something bad without sacrificing anything of comparable moral importance, we are morally obligated to do so — regardless of proximity. This utilitarian principle, formalised into the effective altruism movement by Singer, William MacAskill, and others, produces uncomfortable conclusions: buying a luxury item when that money could save a child's life is morally equivalent to letting the child drown. The movement has channelled hundreds of millions of dollars to highly cost-effective charities and raised serious philosophical questions about how we value distant lives and future generations.

Source: Singer, P., 'Famine, Affluence and Morality', Philosophy & Public Affairs (1972)