Abstract: There are two fundamental principles in eighteenth century's Enlightenment:rational criticism and naturalism. Instead of the opposite of the Enlightenment, the early German romanticism under the leadership of F. Schlegel inherited and developed the principles of Enlightenment. One of the aims of the romanticism is to stick to the principle of criticism, while avoiding skepticism, and to insist on the principle of naturalism while averting atheism and fatalism. Since there are tension between naturalism and criticism, the other aim of romanticism is to balance that tension, which is accomplished by uniting Kant's idealism and Spinoza's realism in F. Schlegel's philosophy.