 Constructivists and their critics disagree about the role to accord to intuitions in rational justification. According to Scanlon, a valid method of justification in ethics consists in testing the congruence between theoretical assumptions and intuitive moral judgments, that is, judgments to which we normally accord initial credence. It is doubtful that we could avoid all appeal to intuitions as unpromising (Scanlon 1998: 241–247). However, the intuitions on which constructivism relies are not independent moral truths and do not serve as an external foundation for morality (Rawls 2000: 178, 273). Not all constructivists view intuitions as playing a role in rational justification (O’Neill 1989b). But all agree that an adequate metaethics should not be totally revisionary; rather, it should be congruent with common understandings of rationality and morality (Smith 2013: 313). Arguably, this commitment sets constructivism apart from those kinds of projectivist and error theories (Blackburn 1993; Mackie 1977, which claim that evaluative discourse involves a systematic error (Bagnoli 2002; Street 2010; Lillehammer 2011.