According to Isaiah Berlin's influential characterization, value monism holds that there are discoverable, axiomatic ethical principles from which all ethical knowledge may be derived, that ethical reasoning is algorithmic and mechanical, and that it seeks permanent, “final solutions” to all ethical conflicts. Berlin's account of monism oversimplifies and distorts the idea of monism and its relation to liberal values. There is a fundamentally distinct conception of monism, “asymptotic” monism, that is not only compatible with liberty and liberal toleration but is required by these values. I present this alternative through an exposition and defense of Immanuel Kant's monistic conception of ethics and public law, where it finds full expression. Berlin's warnings that monism tends to support political despotism ignore the distinctive character of Kant's asymptotic monism.