Critique of the Kantian philosophy
"Critique of the Kantian philosophy" is a criticism Arthur Schopenhauer appended to the first volume of his "The World as Will and Representation" (1818). He wanted to show Immanuel Kant's errors so that Kant's merits would be appreciated and his achievements furthered.
19th-century philosophy
One of the first philosophers to attempt to grapple with Kant's philosophy was Johann Gottlieb Fichte, whose development of Kantian metaphysics became a source of inspiration for the Romantics. In "Wissenschaftslehre", Fichte argues that the self posits itself and is a self-producing and changing process.