  Jackson seeks to describe a reductive analysis of ethical terms that understands them as picking out the properties that play a certain role in the conceptual network determined by mature folk morality. The most worrying difficulty with Jackson’s approach is that this looks unpromising as a reductive analysis, as there is a term in it that appears decidedly evaluative in character: “mature” (Yablo 2000). “Mature” had better not apply to any old terminal point our ethical development may happen to take us to, but only to a terminus we could arrive at by good, reasonable ethical discussion and argument. One possible answer in the spirit of the wider theory might be to say that “mature” picks out whatever plays the “mature” role in mature folk morality. But that seems circular. After all, maturity in current folk morality is plausibly pretty contested. There are many ways morality could develop to a more settled state, and we are liable to differ about which of them we count as maturation and which we would describe less favorably. So a naturalistic account of ‘maturity’ fails to pick out one set of platitudes as being the unique platitudes of mature folk morality. And if we attempt to narrow down the range of sets of platitudes that might count as “mature folk morality” by attempting to specify the best candidate for mature folk morality, a central question seems to be getting begged. Or, as we might say, echoing Moore, left open.