 In reply to this line of criticism, Papineau could appeal to the compositionality of desires (in the way that he appeals, in the case of a closely related problem, to the compositionality of beliefs; cf. Papineau 1993, 75 and 82–83). In short, he could argue that once some basic desires and beliefs have content, the concepts that are the constituents of these attitudes acquire contents as well (in virtue of the role they play within these attitudes), and these concepts can then be recombined to produce further desires which may be entirely novel, incapable of contributing to their own satisfaction, or directed at actions that are neither fitness-enhancing nor rewarding. However, this solution would have to be spelled out in detail in order to be fully convincing.