Abstract
The author considers how constructivism, presently known to us essentially as a theory for generating rules of social cooperation, embodies a certain conception of justification that in turn may be thought of as a general theory. It is argued that moral realism and projectivism are by turns platitudinous and unsatisfactory as conceptions of justification; by contrast the general conception of justification in constructivism makes sense of reason giving and coherent rivalry. The author argues that once the right picture of justification is in place, the picture constructivism illustrates or embodies, the problem of moral ontology disappears.