 In sum, “rational” utilitarianism is critical and empirical rather than deductive. It resolutely though judiciously embraces indefeasible moral rights as necessary conditions of general happiness, making utilitarianism rigorously and uncompromisingly liberal. And it was also evolutionary, much like Sidgwick’s. For both Spencer and Sidgwick, utilitarian practical reasoning exposes, refines and systematizes our underlying moral intuitions, which have thus far evolved in spite of their under-appreciated utility. Whereas Spencer labeled this progress towards “rational” utilitarianism, Sidgwick more appropriately called this “progress in the direction of a closer approximation to a perfectly enlightened [empirical] Utilitarianism” (Sidgwick, 1907: 455).