 Authors who recognize partial preferences usually give them priority, and consider total preferences to be completely determined by the partial preferences. In other words, they assume that a total preference relation is uniquely determined by the partial preference relations through a process of aggregation. There are different views on the nature of this process. According to a quantitative approach, each partial preference is connected with a cardinal partial utility function for the aspect in question, and the total preference relation can be obtained by aggregating these partial utility functions using an appropriate set of weights. This requires strong assumptions of preference independence in order to justify additivity of utility (Keeney and Raiffa 1993). 