 The relation between incommensurability and the Sneedean reduction relation is to some extent discussed in Balzer et al. (1987, chapter VI.7). The authors consider an exact reduction relation as a certain relation between potential models of the respective theories. More interesting for physical real-life examples is the approximate version which is obtained as a “blurred exact reduction” by means of a subclass of an empirical uniformity on the classes of potential models. The Kepler-Newton case is discussed as an example of approximate reduction. The discussion of incommensurability suffers from the notorious difficulties of explicating such notions as “meaning preserving translation”. There is an interesting application of the interpolation theorem of meta-mathematics which yields the result that, roughly speaking, (exact) reduction implies translation. However, the relevance of this result is questioned in Balzer et al. (1987, 312 ff). Thus the discussion eventually ends up as inconclusive, but the authors admit the possibility of a spectrum of incommensurabilities of different degrees in cases of pairs of reduced/reducing theories. 