That life is worth living is the most necessary of assumptions and, were it not assumed, the most impossible of conclusions.

More from George Santayana

• American life is a powerful solvent. It seems to neutralize every intellectual element, however tough and alien it may be, and to fuse it in the native good will, complacency, thoughtlessness, and optimism.
• Beauty is a pledge of the possible conformity between the soul and nature, and consequently a ground of faith in the supremacy of the good.
• Fanaticism consists in redoubling your efforts when you have forgotten your aim.
• Happiness is the only sanction of life; where happiness fails, existence remains a mad and lamentable experiment.
• I like to walk about amidst the beautiful things that adorn the world; but private wealth I should decline, or any sort of personal possessions, because they would take away my liberty.
• Only the dead have seen the end of war.