 Historically, utilitarians have used the term ‘utility’ rather than ‘welfare’ and utility has been defined variously as pleasure, happiness, or preference-satisfaction, etc. Jeremy Bentham, the historical father of utilitarianism, argued that the experience of pleasure was the only thing with intrinsic value, and all other things had instrumental value insofar as they contribute to the experience of pleasure or the avoidance of pain. His intellectual successor, John Stuart Mill, broadened this theory of intrinsic value to include happiness, or fulfillment. Modern philosophers since Kenneth Arrow, though, tend to argue that intrinsic value consists in preference-satisfaction, i.e. in individuals’ having what they want. So, for instance, the principle for distributing economic benefits for preference utilitarians is to distribute them so as to maximize preference-satisfaction. The welfare function for such a principle has a relatively simple theoretical form requiring the distribution maximizing the arithmetic sum of all satisfied preferences (unsatisfied preferences being negative), weighted for the intensity of those preferences. To accommodate uncertainty with respect to outcomes the function is modified so that expected utility, rather than utility, is maximized (see  consequentialism).  