 For Sidgwick, Spencer’s utilitarianism was merely seemingly deductive even though it purported to be more scientific and rigorously rational than “empirical” utilitarianism. However, deductive hedonism fails because, contrary to what deductive hedonists like Spencer think, no general science of the causes of pleasure and pain exists, insuring that we will never succeed in formulating universal, indefeasible moral rules for promoting happiness. Moreover, Spencer only makes matters worse for himself in claiming that we can nevertheless formulate indefeasible moral rules for hypothetically perfectly moral human beings. First of all, in Sidgwick’s view, since we can’t possibly imagine what perfectly moral humans would look like, we could never possibly deduce an ideal moral code of “absolute” ethics for them. Secondly, even if we could somehow conceptualize such a code, it would nevertheless provide inadequate normative guidance to humans as we find them with all their actual desires, emotions and irrational  proclivities.[17]  For Sidgwick, all we have is utilitarian common-sense, which we can, and should, try to refine and systematize according the demands of our changing  circumstances.[18]