  Maddy seems to want to have her cake and eat it. The reason for mathematics' credibility is supposed to be its application in science. But why should the fact that mathematics features in our best science be a reason for believing mathematicians' utterances—that is, a reason for taking them to be true? The suspicion is that if featuring in best science is the mark of credibility, it should be scientific standards that ultimately determine mathematical theories' acceptability. Maddy has indeed cited a feature distinguishing mathematics from pure astrology, as she points out (2007, 390); but what still remains unclear is why this feature should make mathematics rather than science authoritative with respect to questions in mathematics proper. Thus it seems that she has not explained how one can consistently be a mathematical naturalist about mathematical theories but a scientific naturalist about everything else, including the truth and nature of mathematics. More generally, given that a practice issues in truth-evaluable statements, it seems that one cannot advocate X-standards as the arbiters of these statements' acceptability while simultaneously advocating a different set of standards, the Y-standards, as arbiters of whether or not the statements should be taken as true, how they should be interpreted, etc. Notice that this is a problem faced exclusively by heterogeneous as opposed to uniform  naturalism.