Methodological naturalism fits more naturally with some areas of philosophy than others. It is perhaps not hard to understand, at least in outline, how work in areas like metaphysics, philosophy of mind, meta-ethics and epistemology might be aimed at the construction of synthetic theories supported by a posteriori evidence. But in other philosophical areas the methodologically naturalistic project may seem less obviously applicable. In particular it might be unclear how it applies to those areas of philosophy that make claims about mathematics, first-order morality or modality.