The most characteristically Kantian of Kant's objections to moral philosophies other than his own is that they are heteronomous, locating the moral law outside the will. In the Groundwork (1785) and the second Critique (1788) we find him making this objection against Wolff, Hutcheson, Montaigne, Epicurus, the Stoics, and others—but not Aristotle (e.g., KpV 33ff, G 441). In the Doctrine of Virtue
... [Show full abstract] (1797), however, Kant singles out Aristotle, but for a different kind of criticism altogether. Here, Kant complains that Aristotle's doctrine of the mean cannot guide action in a sufficiently determinate way, and, since any adequate theory should do this, Aristotle's theory should be rejected. In short, Aristotle's ethics is prey to IAGO: the insufficiently action-guiding objection. My plan in this paper is to probe the theoretical differences underlying the objection, primarily by focusing on their different conceptions of how difficult it is—and should be—to know what morality requires of us, and secondarily on what responses an Aristotelian could make to Kant. 1. Kant v. Aristotle: The insufficiently action-guiding objection (IAGO) In the Doctrine of Virtue Kant twice considers Aristotle's doctrine that virtues are means between extremes of excess and deficiency, and twice he rejects it—first because it is false (DV 404), and second because it is useless (DV 432). The two claims are different but not independent: the doctrine is false because it is useless.