  This paper shows that default-based phonologies have the potential to capture
morphophonological generalisations which cannot be captured by non-defaul
theories. In achieving this result, I offer a characterisation of
Underspecification Theory and Optimality Theory in terms of their methods for
ordering defaults. The result means that machine learning techniques for
building non-defualt analyses may not provide a suitable basis for
morphophonological analysis.
