Nietzsche famously groups together Plato and Kant as moralizers in his pithy history of Western metaphysics in Twilight of the Idols. In “The History of an Error,” Kant appears as an inheritor of Plato's fateful error. Plato's mistake is to devalue the human, passionate, temporal world in favor of an eternal, unchanging world governed by reason – the world of “ideas” or “forms.” Plato equates what is good for him (an ascetic life of passion tamed by reason) with what is universally true and locates this truth in the world of ideas. Plato's two-world distinction evolves into the distinction between this world and the next in Christianity, and between the phenomenal and noumenal worlds in Kant. The two-world metaphysic in both Plato and Kant is precisely what facilitates their moralism; the unchanging and exacting demands of the true world obligate us in opposition to our passions, desires, histories, and particular situations. Both Plato and Kant come to stand as inspiration for approaches to politics driven by a sterile reason, where moral claims anchored in a universal reason constrain and direct politics from without. My purpose in the next two chapters is to show that in two banner works by the apparent father figures of political moralizing there are critiques of calculable responsibility as a driver of moralism. I even suggest that we may overlook Plato's and Kant's grapplings with calculable responsibility, in part, because of our own captivation by it. We do not properly register the invocations of incalculable responsibility in Plato's Republic and Kant's Groundwork of the Metaphysic of Morals because we read these texts through the lens of calculable responsibility and perhaps also because they leave a respectable place – in the Groundwork, a central place – for morality (and therefore calculable responsibility).

Plato's reputation as a moralizer is somehow enhanced by the fact that scholars often consider his student Aristotle as the contrasting exemplar of the nonmoralized path not taken in the trajectory of Western philosophy. Martha Nussbaum argues that Aristotle recognizes “the fragility of human goodness,” namely the vulnerability of our ethical goodness to contingency. In contrast, she argues, Plato (at least in his “middle dialogues,” including the Republic) imagines an ethical goodness in which we shed the relationships and passions that make us vulnerable to contingency.