  How is moral disagreement supposed to show that our moral beliefs are unsafe? Consider a person a whose beliefs about a set of contested moral topics are true. The beliefs are safe only if a, by using the same methods, could not easily have formed beliefs that contradict her actual ones in circumstances where the moral facts remain the same. Now, what disagreement about a’s beliefs entails is that some people have in fact formed beliefs that contradict a’s actual ones in circumstances where (we are supposing) the moral facts remain the same. So, if (some of) those persons have used the same methods as a and if the existence of those persons accordingly indicates that a could easily have formed those beliefs as well by using those methods (on the ground, perhaps, that they have grown up in similar social or cultural circumstances and have been exposed to similar types of education), then it also indicates that a’s beliefs are unsafe.