 Second, a welfarist theory distinguishes between the well-being of each agent and the criteria that determine the structure of the social welfare  function.[31]  The theory, that is, distinguishes what makes an individual’s life go better and the concerns that determine how one integrates the well-being of individuals into “social welfare.” These latter concerns weigh the well-being of individual J against the well-being of individual K. Consider two states of the world s and t. Agent J’s well-being is higher in state s than in state t while agent K’s well-being is higher in state t than in state s. To rank the two states, society must determine the relative importance of the well-being of the two individuals. 