 A unificationist account of metaphysical explanation is an account according to which such explanations aim to unify the beliefs implicated in metaphysical theorizing. On this view, roughly speaking, a particular derivation is a metaphysical explanation just in case it is an instance of an argument pattern that unifies metaphysical beliefs. Several things can be said in favor of this view. If you are no fan of grounding, the fact that it takes metaphysical explanation to be something completely independent of whatever determinative (grounding) relations there happen to be (or not), will count as a big point in its favor. Another positive is the fact that it is an account of metaphysical explanation that makes unusually good sense of the link between explanation and understanding. Unificationism corresponds to an intuitive way of thinking about understanding: we understand better when we can derive large amounts of information from a fairly small number of premises and a small number of argument patterns. This is because the ability to do so suggests an ability to identify connections between things; to fit things together. Yet the resulting account is not (just) psychological. As Friedman points out, explanatoriness remains in an important sense objective if “what is scientifically comprehensible is constant for a relatively large class of people” (1974: 7–8).