If ethical expressivism is true, then moral judgements are motivational desire-like states and do not robustly represent reality. This gives rise to the problem of how to understand moral error. How can we be mistaken if there is no moral reality to be mistaken about? The standard expressivist explanation of moral doubt is couched in terms of our fear that our judgements may not survive improvements to our epistemic situation. There is a debate between Egan (Australas J Philos 85(2):205 -219, 2007), Blackburn (Australas J Philos 87(2):201-213, 2009), Kohler (Australas J Philos 93(1):161-165, 2015) and Ridge (J Ethics Soc Philos 9(3):1-21, 2015) on the adequacy of this explanation when it comes to the phenomenon of fundamental moral error. This paper is my contribution to the debate. I argue, contrary to Blackburn and Ridge, that expressivism is committed to some first-order anti-realist sounding claims, and thus quasi-realism fails. If expressivism is true, none of us can coherently believe we might be fundamentally mistaken. However, contrary to Egan and Kohler, I do not think this is bad. Expressivists can still do what motivated the project of quasi-realism in the first place: they can interpret, make sense of, and vindicate ordinary moral discourse. I end by showing it yields some positive results for moral philosophers too - it effectively amounts to a transcendental argument against unhealthy moral scepticism.
