 Let’s stipulate that both Nina and Aleksi come to know what they wanted by testimony. (Set aside any general worries about testimonial knowledge, and assume that in both cases they have sufficient reason to trust the word of the person they’re asking.) It seems to many that while what Nina does is entirely unproblematic, there is something off, if not outright wrong, with Aleksi’s moral deference. More generally, one commonly accepted qualification is that moral deference is problematic when one forms a moral belief solely on the basis of testimony, instead of, for example, reflecting on the matter as a result of another’s expressing an opinion. Another common qualification is that problematic testimony concerns pure moral content whose truth doesn’t hang on empirical assumptions. It is not problematic to change one’s opinion about an impure moral matter on the basis of testimony that concerns a morally relevant empirical fact, as when someone comes to believe it is wrong to eat fish on the basis of being informed that fish feel pain (Fletcher 2016). In brief, it seems that you shouldn’t change your mind on a purely moral matter just because someone tells you (even if you have no particular reason to doubt them).