Schelling's philosophy of religion was the work of a lifetime of philosophical activity, considerably larger in ambition and accomplishment than the loose assemblage of questions usually collected under that name: the existence of deity, responsibility for evil, and immortality. Schelling is the most difficult of the "German Idealists" to fit into a consistent historical narrative and the least amenable of that generation of thinkers to philosophical reconstruction or contemporary retrieval. Part of this is due to entanglements early in his career with philosophical alliances and polemics, part with what the public perceived as shifts in his philosophical focus, and part with a refusal to stay on the high road of Kant's narrative about modernity's conflicting claims of rationalism and empiricism, which could only be reconciled in a critical recognition of the secure but hybrid nature of empirical knowledge – its content derived from sensation, its form secured by empty concepts furnished by reason. Schelling appreciated well enough Kant's conceptual precision; he chafed, though, at Kant's legislation of the limits of philosophy's competence: a metaphysics of experience, a formalistic morality, strictures placed on the artist's and scientist's imagination, and the reduction of religion to morality without remainder – which meant, in Germany, accommodation with the political status quo. In his willingness to return to pre-critical sources of inspiration such as Plato, Spinoza, and Leibniz, his incorporation of religious themes voiced by heterodox figures such Giordano Bruno, Joachim di Fiore, and Jakob Böhme, and his seemingly quixotic fight against Newtonian optics and the methods of hypothesis-formation and experimental test practiced by the working scientists of his day, Schelling seemed in his own day to court ridicule.