  Another type of self-defeat or incoherence is epistemic, as contrasted with the “strict” type just indicated. An argument is epistemically self-defeating, we may say, if we by affirming it commit ourselves to thinking that at least one of its elements is unjustified (rather than false). That is the type of incoherence that Derek Parfit has tried to saddle moral non-cognitivists with by stressing (like Jackson) that they are committed to non-cognitivism about theoretical rationality as well. Parfit takes the latter view to imply that “to call a thing rational is not to state a matter of fact” (2011, 409). And the problem for the moral non-cognitivist which he discerns is that “[i]f there could not be truths about what it is rational to believe […] it could not be rational to believe anything”, including moral non-cognitivism.