Schaffner, Dizadji-Bahmani et al. (2010), and Butterfield (2011a&b) have developed variants of the Nagel model that address its criticisms

In response to those critiques, some, like Schaffner and Dizadji-Bahmani et al. (2010) and Butterfield (2011a&b) have developed variants of the Nagel model that retain its spirit but avoid many of the problems faced by the original. Prominent suggestions concern refinements of the logical framework in which Nagelian reduction is described (Dizadji-Bahmani, Frigg, and Hartmann (2010) and Butterfield (2011a)) as well as a relaxation of the condition that reductions must be complete. The idea i