 A very different popular explanation of the problematic nature of moral deference appeals to the notion of moral understanding: while we can acquire moral knowledge by testimony, we will not (easily or at all) acquire moral understanding that way, and moral understanding is important for moral worth, or deserving credit for one’s action (Hills 2009). For Alison Hills (2016), moral understanding is a form of “cognitive control”, roughly the ability to grasp and articulate why certain features make an action (say) wrong, and consequently what would need to be different for it to be right. Callahan (2018) argues that having the kind of cognitive abilities that Hills highlights doesn’t suffice for moral worth, since possessing them is consistent with being motivated by features that are not reasons for acting. On her alternative sentimentalist account, moral understanding itself requires also having fitting affective and motivational responses towards the understood propositions and the relevant explanatory relationships (Callahan 2018: 451–452). For example, understanding that a practice is wrong because it’s racist involves a disposition to be angry or sad about it because it’s racist (or about the features that make it racist), and a willingness to abstain from or intervene in the practice. The problem with deference, then, is that it disincentivizes the sort of reflection and inquiry that would give rise to such responses in addition to the relevant cognitive abilities (Callahan 2018: 454–456; for a very different sentimentalist take, see Howard 2018).