Three of the great sources of meaning in life are the good, the true, and the beautiful, and I aim to make headway on the grand Enlightenment project of ascertaining what, if anything, they have in common. Concretely, if we take a (stereotypical) Mother Teresa, Mandela, Darwin, Einstein, Dostoyevsky, and Picasso, what might they share that makes it apt to deem their lives to have truly mattered? I provide reason to doubt two influential answers, noting a common flaw that supernaturalism and consequentialism share. I instead develop their most plausible rival, a naturalist and non-consequentialist account of what enables moral achievement, intellectual reflection, and aesthetic creation to confer great meaning on a person's life, namely, the idea that they do so insofar as a person transcends an aspect of herself in some substantial way. I criticize several self-transcendence theories that contemporary philosophers have advanced, before presenting a new self-transcendence view and defending it as the most promising.