In the "Metaphysik Herder" (V-MP/Herder) we have the beginning of Kant's ambivalent relation to idealism and his first recorded thoughts on George Berkeley, who later came to be one of his philosophical arch-enimies. By examining Kant's treatment of Berkeley in this work we will therefore be able to plot the beginning of the trajectory of Kant's conception of idealism in general, and on his view of Berkeley's philosophy in particular.