  This is just a sketch of an argument, of course, and it faces serious challenges. One is to clarify the notion of a “method”, which is required in order to make sense of the claim that different people use the same methods to arrive at incompatible moral beliefs. Another problem is to explain in more precise terms what it means to say that it could “easily” have happened that someone had formed an opposing belief. It is a tricky task to provide precise definitions of those notions which both render the view that safety is required for knowledge plausible and vindicate the role assigned to disagreement by the indicated argument.