There are different views and definitions of enlightenment. The enlightenment Weishaupt proposed, influenced by the Age of Reason, was through knowledge. The Age of Reason was a move away from mysticism, superstition and religion.
"Enlightenment is man's leaving his self-caused immaturity. Immaturity is the incapacity to use one's own understanding without the guidance of another. Such immaturity is self-caused if its cause is not lack of intelligence, but by lack of determination and courage to use one's intelligence without being guided by another. The motto of enlightenment is therefore: Sapere aude! Have courage to use your own intelligence!" -- Kant