to concede that knowledge is valuable, but only extrinsically so, given that knowledge can be helpful in causing pleasure and avoiding pain. Various arguments have been suggested in the monism-pluralism-dispute. Common-sense seems to favor value pluralism: values are ascribed to a wide range of different things like happiness, liberty, friendship, etc. without any obvious common feature underlying these values. One way to defend value monism is to cast doubt on the reliability of common-sense for technical matters like the distinction between intrinsic and extrinsic value. This strategy is pursued by J. J. C. Smart, who holds that there is a psychological bias to mistake stable extrinsic values for intrinsic values. Value pluralists have often attempted to provide exhaustive lists of all value types, but different theorists have suggested very different lists. These lists seem to constitute arbitrary selections unless a clear criterion could be provided why all and only these items are included. But if a criterion was to be found then such a theory would no longer be pluralistic. This dilemma suggests that pluralism is inadequate as an explanation. One issue closely related to the monism-pluralism-debate is the problem of incommensurability: the question of whether there are incommensurable values. Two values are incommensurable if there is no fact as to whether one is better than or as good as the other: there is no common value scale according to which they could be compared. According to Joseph Raz, career choices between very different paths, for example, whether to become a lawyer or a clarinetist, are cases where incommensurable values are involved. Value pluralists often assert that values belonging to different types are incommensurable with each other. Value monists, by contrast, usually deny that there are incommensurable values. This question is particularly relevant for ethics. If different options available to the agent embody incommensurable values then there seems to be no rational way to determine what ought to be done since there is no matter of fact as to which option is better. Widespread incommensurability would threaten to undermine the practical relevance of ethics and rational choice. Other concepts and distinctions Many evaluative terms are found in everyday language, often with various different meanings. It is important for philosophers to distinguish these different meanings in order to avoid misunderstandings. One such distinction is between a predicative and an attributive sense of good and bad. In the attributive sense, an entity