 Most philosophers take the evaluated items to be propositions. In contrast to this, economists commonly conceive of items as bundles of  goods, represented as   vectors.[1]  However, this approach has a difficult ambiguity. If preferences are subjective evaluations of the alternatives, then what matters are the results that can be obtained with the help of these goods, not the goods themselves. Whether an agent has a preference e.g. for a batch of wood over a crate of bricks will depend on whether she intends to use it to generate warmth, build a shelter or create a sculpture. Economists have tried to solve this ambiguity by coupling preferences over goods with household production functions (Lancaster 1966, Becker and Michael 1973); but as these functions are very difficult to determine, it is often thought more parsimonious to stick with the sentential or propositional representations of states of the world. 