I believe in one thing — that only a life lived for others is a life worth living.

The quote frames human worth not in terms of achievement, fame, or private happiness, but in outward-directed purpose. “Only a life lived for others” suggests that meaning arises from service, solidarity, and the alleviation of others’ suffering—an ethical stance that treats the self as fundamentally relational rather than isolated. Read in the context of Einstein’s broader moral outlook, it also implies a critique of egoism and purely careerist ambition: intellectual brilliance or success is insufficient unless it is joined to humane ends. The aphoristic certainty (“I believe in one thing”) gives the statement the force of a personal creed, presenting altruism as the central measure of a worthwhile life.