Fanaticism consists in redoubling your efforts when you have forgotten your aim.

George Santayana (1863–1952), a Spanish-American philosopher and cultural critic, developed this aphorism in the early 20th century amid his broader skepticism about ideological zeal and moral crusading. The line is commonly traced to his book *Reason in Society* (part of *The Life of Reason*), where he examines how social institutions and collective passions can outlive or obscure the rational purposes that originally justified them. Santayana had watched modern politics and reform movements harden into dogma, and he repeatedly warned that intense conviction is not the same as clear thought. The remark reflects his characteristic preference for reflective reason over compulsive activism.

Santayana defines fanaticism not as mere intensity but as misdirected intensity: the will keeps accelerating after the mind has lost sight of the goal. The phrase suggests that zeal can become self-perpetuating—effort turns into an end in itself, insulated from reflection, evidence, or the original human need the effort was meant to serve. It is a critique of movements (political, religious, moral) that substitute discipline, sacrifice, or purity tests for genuine purpose. The warning is practical as well as philosophical: when means eclipse ends, people may commit greater harms precisely because they feel more certain and more “committed.”