Affirmation of life is the spiritual act by which man ceases to live unreflectively and begins to devote himself to his life with reverence in order to raise it to its true value. To affirm life is to deepen, to make more inward, and to exalt the will to live.

Schweitzer contrasts an unexamined, instinctive “will to live” with a consciously chosen, ethically charged commitment to life. “Affirmation of life” is presented as a spiritual discipline: to live reflectively, with reverence, and to treat one’s own existence as something to be cultivated toward its “true value.” The second sentence suggests that affirmation is not mere optimism but an intensification and ennobling of the life-impulse—deepening it inwardly so it becomes responsible and purposeful. Read alongside Schweitzer’s broader ethic of “reverence for life,” the passage implies that authentic self-affirmation tends toward moral seriousness and a heightened respect for life as such, not simply self-indulgence.