The 1786 review of Kant's Groundwork for the Metaphysics of Morals by Hermann Andreas Pistorius raised the objection that Kant's categorical imperative is an "empty formalism" that needs an antecedent conception of the good long before Hegel made the same charge in 1802.  Kant's explicit response to Pistorius in the Critique of Practical Reason is just to double-down on the priority of the right over the good.  However, I suggest that Kant's characterization of humanity as an end in itself as the "ground of a possible categorical imperative" in the Groundwork, on the one hand, and his account of the highest good as the complete object of morality in the second Critique, on the other, together provide a much fuller and satisfactory response to the "empty formalism" objection.